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Connectors for Keling stepper driver

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  • tuscanland
    Hello everyone, I m working on a project to convert a Sherline lathe into a cnc threading machine, I have to mount a nema 34 stepper motor in place of the
    Message 1 of 21 , Jul 17 4:40 PM
      Hello everyone, I'm working on a project to convert a Sherline lathe into a cnc threading machine, I have to mount a nema 34 stepper motor in place of the original dc motor that comes with the lathe, I got all the material needed but to my surprise the driver came with no connectors, this link is to the driver in question: http://www.cnc4pc.com/Store/osc/product_info.php?products_id=415

      If anyone could be so kind to point me in the right direction I'd appreciate it as this is my first attempt to assemble cnc components, I've searched for connectors suitable for my driver, but can't find them.

      By the way, thanks for adding me to the group.

      Davide Ghelarducci
    • Manfred Vormbaum
      If you double click on this link: KL11080Wiring on the page
      Message 2 of 21 , Jul 17 7:03 PM
        If you double click on this link:
        KL11080Wiring<http://www.automationtechnologiesinc.com/wp-content/plugins/download-monitor/download.php?id=242>
        on
        the page in question all will be revealed...

        Manfred

        On Wed, Jul 17, 2013 at 7:40 PM, tuscanland <tuscanland@...> wrote:

        > **
        >
        >
        > Hello everyone, I'm working on a project to convert a Sherline lathe into
        > a cnc threading machine, I have to mount a nema 34 stepper motor in place
        > of the original dc motor that comes with the lathe, I got all the material
        > needed but to my surprise the driver came with no connectors, this link is
        > to the driver in question:
        > http://www.cnc4pc.com/Store/osc/product_info.php?products_id=415
        >
        > If anyone could be so kind to point me in the right direction I'd
        > appreciate it as this is my first attempt to assemble cnc components, I've
        > searched for connectors suitable for my driver, but can't find them.
        >
        > By the way, thanks for adding me to the group.
        >
        > Davide Ghelarducci
        >
        >
        >


        [Non-text portions of this message have been removed]
      • danieltbarber
        Davide, Since your controller has screw terminals I am assuming that you are looking for an alternative to hard wiring the cable to the motor. I use circular,
        Message 3 of 21 , Jul 18 7:07 AM
          Davide,

          Since your controller has screw terminals I am assuming that you are looking for an alternative to hard wiring the cable to the motor. I use circular, thread locking connectors sourced from from DigiKey (www.digikey.com), part numbers CP-1234-ND and CP-1034-ND. The female connector is panel mount and the mating male connector is in-line. I mount the female connector to the motor via a machined mounting plate. The solder pins on the female connector needs to be protected from possible contact with metal shavings, so before soldering I slip a length of heat shrink tubing over each wire and after soldering I apply a conformal coating (nail polish will work) to each connection. After the conformal coating has dried, slide the heat shrink tubing in place and apply heat.

          Regards,

          Dan

          --- In SherlineCNC@yahoogroups.com, "tuscanland" <tuscanland@...> wrote:
          >
          > Hello everyone, I'm working on a project to convert a Sherline lathe into a cnc threading machine, I have to mount a nema 34 stepper motor in place of the original dc motor that comes with the lathe, I got all the material needed but to my surprise the driver came with no connectors, this link is to the driver in question: http://www.cnc4pc.com/Store/osc/product_info.php?products_id=415
          >
          > If anyone could be so kind to point me in the right direction I'd appreciate it as this is my first attempt to assemble cnc components, I've searched for connectors suitable for my driver, but can't find them.
          >
          > By the way, thanks for adding me to the group.
          >
          > Davide Ghelarducci
          >
        • Shannon Haworth
          Another approach: http://makezine.com/review/tool-review-nema-23-stepper-motor-covers/ Plan on trying these soon. Shannon ... [Non-text portions of this
          Message 4 of 21 , Jul 18 8:50 AM
            Another approach:
            http://makezine.com/review/tool-review-nema-23-stepper-motor-covers/

            Plan on trying these soon.

            Shannon

            On Thu, Jul 18, 2013 at 10:07 AM, <dtbarber@...> wrote:

            > **
            >
            >
            > Davide,
            >
            > Since your controller has screw terminals I am assuming that you are
            > looking for an alternative to hard wiring the cable to the motor. I use
            > circular, thread locking connectors sourced from from DigiKey (
            > www.digikey.com), part numbers CP-1234-ND and CP-1034-ND. The female
            > connector is panel mount and the mating male connector is in-line. I mount
            > the female connector to the motor via a machined mounting plate. The solder
            > pins on the female connector needs to be protected from possible contact
            > with metal shavings, so before soldering I slip a length of heat shrink
            > tubing over each wire and after soldering I apply a conformal coating (nail
            > polish will work) to each connection. After the conformal coating has
            > dried, slide the heat shrink tubing in place and apply heat.
            >
            > Regards,
            >
            > Dan
            >
            >
            > --- In SherlineCNC@yahoogroups.com, "tuscanland" <tuscanland@...> wrote:
            > >
            > > Hello everyone, I'm working on a project to convert a Sherline lathe
            > into a cnc threading machine, I have to mount a nema 34 stepper motor in
            > place of the original dc motor that comes with the lathe, I got all the
            > material needed but to my surprise the driver came with no connectors, this
            > link is to the driver in question:
            > http://www.cnc4pc.com/Store/osc/product_info.php?products_id=415
            > >
            > > If anyone could be so kind to point me in the right direction I'd
            > appreciate it as this is my first attempt to assemble cnc components, I've
            > searched for connectors suitable for my driver, but can't find them.
            > >
            > > By the way, thanks for adding me to the group.
            > >
            > > Davide Ghelarducci
            > >
            >
            >
            >


            [Non-text portions of this message have been removed]
          • tuscanland
            Thanks to every one for the feedback, I found all the info given to be very useful. Dan, those connectors look great, I surely will try them out. I should have
            Message 5 of 21 , Jul 18 7:41 PM
              Thanks to every one for the feedback, I found all the info given to be very useful. Dan, those connectors look great, I surely will try them out. I should have enough time this coming week end to work on my little project and I'll post some pictures among the group's photos. Please note, turning a Sherline lathe into a cnc threading machine in the fashion that I have in mind isn't mine, I picked up the idea from Tryally, who's videos can be found on Youtube
              Thanks again for the help.
              Davide Ghelarducci

              --- In SherlineCNC@yahoogroups.com, dtbarber@... wrote:
              >
              > Davide,
              >
              > Since your controller has screw terminals I am assuming that you are looking for an alternative to hard wiring the cable to the motor. I use circular, thread locking connectors sourced from from DigiKey (www.digikey.com), part numbers CP-1234-ND and CP-1034-ND. The female connector is panel mount and the mating male connector is in-line. I mount the female connector to the motor via a machined mounting plate. The solder pins on the female connector needs to be protected from possible contact with metal shavings, so before soldering I slip a length of heat shrink tubing over each wire and after soldering I apply a conformal coating (nail polish will work) to each connection. After the conformal coating has dried, slide the heat shrink tubing in place and apply heat.
              >
              > Regards,
              >
              > Dan
              >
              > --- In SherlineCNC@yahoogroups.com, "tuscanland" <tuscanland@> wrote:
              > >
              > > Hello everyone, I'm working on a project to convert a Sherline lathe into a cnc threading machine, I have to mount a nema 34 stepper motor in place of the original dc motor that comes with the lathe, I got all the material needed but to my surprise the driver came with no connectors, this link is to the driver in question: http://www.cnc4pc.com/Store/osc/product_info.php?products_id=415
              > >
              > > If anyone could be so kind to point me in the right direction I'd appreciate it as this is my first attempt to assemble cnc components, I've searched for connectors suitable for my driver, but can't find them.
              > >
              > > By the way, thanks for adding me to the group.
              > >
              > > Davide Ghelarducci
              > >
              >
            • danieltbarber
              Davide, Glad you found the connector info useful. I have uploaded a drawing in DXF format for the bracket I make for mounting the connector to a NEMA 23
              Message 6 of 21 , Jul 19 8:38 AM
                Davide,

                Glad you found the connector info useful. I have uploaded a drawing in DXF format for the bracket I make for mounting the connector to a NEMA 23 motor. You should be able to scale the drawing to work with a NEMA 34. I have also uploaded a picture of the bracket and connectors mounted to a NEMA 23.

                Based on your original post, it appears that your modification is to drive the headstock with a stepper motor for threading. I recently made such a modification to my lathe and it works great using a 2.8 amp 425 oz/in NEMA 23 motor and a KL4030 drive. I use a Pic micro-controller to provide the step and direction signals and a user interface allowing control of Start/Stop, enable/disable, forward/reverse, RPM up and RPM down, and a LED display. If interested, I will post pictures of that system as well.

                Regards,

                Dan



                --- In SherlineCNC@yahoogroups.com, "tuscanland" <tuscanland@...> wrote:
                >
                > Thanks to every one for the feedback, I found all the info given to be very useful. Dan, those connectors look great, I surely will try them out. I should have enough time this coming week end to work on my little project and I'll post some pictures among the group's photos. Please note, turning a Sherline lathe into a cnc threading machine in the fashion that I have in mind isn't mine, I picked up the idea from Tryally, who's videos can be found on Youtube
                > Thanks again for the help.
                > Davide Ghelarducci
                >
                > --- In SherlineCNC@yahoogroups.com, dtbarber@ wrote:
                > >
                > > Davide,
                > >
                > > Since your controller has screw terminals I am assuming that you are looking for an alternative to hard wiring the cable to the motor. I use circular, thread locking connectors sourced from from DigiKey (www.digikey.com), part numbers CP-1234-ND and CP-1034-ND. The female connector is panel mount and the mating male connector is in-line. I mount the female connector to the motor via a machined mounting plate. The solder pins on the female connector needs to be protected from possible contact with metal shavings, so before soldering I slip a length of heat shrink tubing over each wire and after soldering I apply a conformal coating (nail polish will work) to each connection. After the conformal coating has dried, slide the heat shrink tubing in place and apply heat.
                > >
                > > Regards,
                > >
                > > Dan
                > >
                > > --- In SherlineCNC@yahoogroups.com, "tuscanland" <tuscanland@> wrote:
                > > >
                > > > Hello everyone, I'm working on a project to convert a Sherline lathe into a cnc threading machine, I have to mount a nema 34 stepper motor in place of the original dc motor that comes with the lathe, I got all the material needed but to my surprise the driver came with no connectors, this link is to the driver in question: http://www.cnc4pc.com/Store/osc/product_info.php?products_id=415
                > > >
                > > > If anyone could be so kind to point me in the right direction I'd appreciate it as this is my first attempt to assemble cnc components, I've searched for connectors suitable for my driver, but can't find them.
                > > >
                > > > By the way, thanks for adding me to the group.
                > > >
                > > > Davide Ghelarducci
                > > >
                > >
                >
              • Davide Ghelarducci
                Hi Dan,   nice to hear back from you, I ve wired everything correctely so far, just need to wait for the connectors to arrive and I m all good to go. For now
                Message 7 of 21 , Jul 21 8:25 PM
                  Hi Dan,
                   
                  nice to hear back from you, I've wired everything correctely so far, just need to wait for the connectors to arrive and I'm all good to go.
                  For now I'll go ahead with my plan about modifying the lathe, meaning I'll just use the threading attachment made by Sherline, driving the gears using the nema 34 stepper.
                  I was under the impression that the 425 oz/in would have worked as well, but just to be on the safe side I've opted for the more powerful nema 34.
                  I'm not sure how you are threading on the lathe, do you use the threading attachment in the same fashion that I plan to do, or do you thread using a mathematical formula combining spindle speed in conjunction with the appropriate feed rate on the z axis?
                  I sure would be interested to see your pictures when you have time to upload them.
                  Thanks for uploading the dxf files, I'll go look for them now.
                  Best regards
                  Davide

                  ________________________________
                  From: "dtbarber@..." <dtbarber@...>
                  To: SherlineCNC@yahoogroups.com
                  Sent: Friday, July 19, 2013 11:38 AM
                  Subject: [SherlineCNC] Re: Connectors for Keling stepper driver


                   

                  Davide,

                  Glad you found the connector info useful. I have uploaded a drawing in DXF format for the bracket I make for mounting the connector to a NEMA 23 motor. You should be able to scale the drawing to work with a NEMA 34. I have also uploaded a picture of the bracket and connectors mounted to a NEMA 23.

                  Based on your original post, it appears that your modification is to drive the headstock with a stepper motor for threading. I recently made such a modification to my lathe and it works great using a 2.8 amp 425 oz/in NEMA 23 motor and a KL4030 drive. I use a Pic micro-controller to provide the step and direction signals and a user interface allowing control of Start/Stop, enable/disable, forward/reverse, RPM up and RPM down, and a LED display. If interested, I will post pictures of that system as well.

                  Regards,

                  Dan


                  --- In mailto:SherlineCNC%40yahoogroups.com, "tuscanland" <tuscanland@...> wrote:
                  >
                  > Thanks to every one for the feedback, I found all the info given to be very useful. Dan, those connectors look great, I surely will try them out. I should have enough time this coming week end to work on my little project and I'll post some pictures among the group's photos. Please note, turning a Sherline lathe into a cnc threading machine in the fashion that I have in mind isn't mine, I picked up the idea from Tryally, who's videos can be found on Youtube
                  > Thanks again for the help.
                  > Davide Ghelarducci
                  >
                  > --- In mailto:SherlineCNC%40yahoogroups.com, dtbarber@ wrote:
                  > >
                  > > Davide,
                  > >
                  > > Since your controller has screw terminals I am assuming that you are looking for an alternative to hard wiring the cable to the motor. I use circular, thread locking connectors sourced from from DigiKey (www.digikey.com), part numbers CP-1234-ND and CP-1034-ND. The female connector is panel mount and the mating male connector is in-line. I mount the female connector to the motor via a machined mounting plate. The solder pins on the female connector needs to be protected from possible contact with metal shavings, so before soldering I slip a length of heat shrink tubing over each wire and after soldering I apply a conformal coating (nail polish will work) to each connection. After the conformal coating has dried, slide the heat shrink tubing in place and apply heat.
                  > >
                  > > Regards,
                  > >
                  > > Dan
                  > >
                  > > --- In mailto:SherlineCNC%40yahoogroups.com, "tuscanland" <tuscanland@> wrote:
                  > > >
                  > > > Hello everyone, I'm working on a project to convert a Sherline lathe into a cnc threading machine, I have to mount a nema 34 stepper motor in place of the original dc motor that comes with the lathe, I got all the material needed but to my surprise the driver came with no connectors, this link is to the driver in question: http://www.cnc4pc.com/Store/osc/product_info.php?products_id=415
                  > > >
                  > > > If anyone could be so kind to point me in the right direction I'd appreciate it as this is my first attempt to assemble cnc components, I've searched for connectors suitable for my driver, but can't find them.
                  > > >
                  > > > By the way, thanks for adding me to the group.
                  > > >
                  > > > Davide Ghelarducci
                  > > >
                  > >
                  >




                  [Non-text portions of this message have been removed]
                • danieltbarber
                  Davide, I have created a photo album showing my approach for driving the spindle head with a stepper motor. Once approved by the moderator, I will add
                  Message 8 of 21 , Jul 22 2:17 PM
                    Davide,

                    I have created a photo album showing my approach for driving the spindle head with a stepper motor. Once approved by the moderator, I will add comments and more explanation.

                    Regarding your question about how I am threading on the lathe, I use MACH3 and a single 60 degree lathe bit for CNC threading. There is a lot of information available about CNC threading with MACH3, but fundamentally, MACH3 uses a spindle index pulse to determine rotary speed and position of the material being threaded and advances the Z-axis the appropriate feed rate to generate the thread. The ability to track spindle speed and position allows threads to be cut in multiple passes, reducing tool loading.

                    The process is simple but torque limitations of the standard Sherline motor results in inconsistent spindle speeds during the threading process. You probably have noticed that spindle speed can change during normal lathe turning processes. MACH3 adjusts to the changes in speed due to tool loading, but when speed changes are pronounced, adjustments in Z-axis speed can result in an inconsistent thread. I have made various modifications to my Sherline lathe to improve threading, including replacing the standard 20-TPI leadscrew with a 5-TPI leadscrew, which allows threading a higher than normal spindle speeds. However, I think driving the spindle head with a proper sized stepper motor is all that one really needs to do. With my current system, I remove 0.005" per pass in free machining steel and even when cutting 20-TPI threads in .5" material, spindle speed remains constant through out the threading process.

                    More when the pictures are posted.

                    Regards,

                    Dan

                    --- In SherlineCNC@yahoogroups.com, Davide Ghelarducci <tuscanland@...> wrote:
                    >
                    > Hi Dan,
                    >  
                    > nice to hear back from you, I've wired everything correctely so far, just need to wait for the connectors to arrive and I'm all good to go.
                    > For now I'll go ahead with my plan about modifying the lathe, meaning I'll just use the threading attachment made by Sherline, driving the gears using the nema 34 stepper.
                    > I was under the impression that the 425 oz/in would have worked as well, but just to be on the safe side I've opted for the more powerful nema 34.
                    > I'm not sure how you are threading on the lathe, do you use the threading attachment in the same fashion that I plan to do, or do you thread using a mathematical formula combining spindle speed in conjunction with the appropriate feed rate on the z axis?
                    > I sure would be interested to see your pictures when you have time to upload them.
                    > Thanks for uploading the dxf files, I'll go look for them now.
                    > Best regards
                    > Davide
                    >
                  • bruce_e_layne
                    Neat project! Thanks for sharing. The last I heard, Mach uses one index pulse per spindle revolution, and as you mentioned, that s not really enough when the
                    Message 9 of 21 , Jul 22 3:00 PM
                      Neat project! Thanks for sharing.

                      The last I heard, Mach uses one index pulse per spindle revolution, and as you mentioned, that's not really enough when the spindle is under load and the RPM varies. LinuxCNC uses a spindle encoder with one index pulse to initiate the threading operation and many pulses per revolution for much better control of spindle speed by frequently updating the current to the spindle motor to maintain a uniform angular velocity.

                      Or, you could use a large stepper motor for the spindle as long as Mach 3 can be configured to use a stepper for the spindle motor when threading, and you don't load it so much that you lose any steps.

                      I'm using LinuxCNC for my mini-lathe project. If I decide to use it for threading, I'll add a spindle encoder and see if I can get LinuxCNC to control the Sherline DC spindle motor.



                      --- In SherlineCNC@yahoogroups.com, dtbarber@... wrote:
                      >
                      > Davide,
                      >
                      > I have created a photo album showing my approach for driving the spindle head with a stepper motor. Once approved by the moderator, I will add comments and more explanation.
                      >
                      > Regarding your question about how I am threading on the lathe, I use MACH3 and a single 60 degree lathe bit for CNC threading. There is a lot of information available about CNC threading with MACH3, but fundamentally, MACH3 uses a spindle index pulse to determine rotary speed and position of the material being threaded and advances the Z-axis the appropriate feed rate to generate the thread. The ability to track spindle speed and position allows threads to be cut in multiple passes, reducing tool loading.
                      >
                      > The process is simple but torque limitations of the standard Sherline motor results in inconsistent spindle speeds during the threading process. You probably have noticed that spindle speed can change during normal lathe turning processes. MACH3 adjusts to the changes in speed due to tool loading, but when speed changes are pronounced, adjustments in Z-axis speed can result in an inconsistent thread. I have made various modifications to my Sherline lathe to improve threading, including replacing the standard 20-TPI leadscrew with a 5-TPI leadscrew, which allows threading a higher than normal spindle speeds. However, I think driving the spindle head with a proper sized stepper motor is all that one really needs to do. With my current system, I remove 0.005" per pass in free machining steel and even when cutting 20-TPI threads in .5" material, spindle speed remains constant through out the threading process.
                      >
                      > More when the pictures are posted.
                      >
                      > Regards,
                      >
                      > Dan
                    • Douglas Vogt
                      Good information here for those that are considering adding a stepper to the spindle for threading. Would it be possible for you to insert a bit of text in
                      Message 10 of 21 , Jul 22 3:25 PM
                        Good information here for those that are considering adding a stepper to the spindle for threading. Would it be possible for you to insert a bit of text in your comments on setting up Mach to do this? There are several YouTube videos on running a spindle via stepper but not too much detail. Specifically, what has to be entered in the Ports & Pins for the spindle and what for the A axis?




                        ________________________________
                        From: "dtbarber@..." <dtbarber@...>
                        To: SherlineCNC@yahoogroups.com
                        Sent: Monday, July 22, 2013 5:17 PM
                        Subject: [SherlineCNC] Re: Connectors for Keling stepper driver - Threading



                         
                        Davide,

                        I have created a photo album showing my approach for driving the spindle head with a stepper motor. Once approved by the moderator, I will add comments and more explanation.

                        Regarding your question about how I am threading on the lathe, I use MACH3 and a single 60 degree lathe bit for CNC threading. There is a lot of information available about CNC threading with MACH3, but fundamentally, MACH3 uses a spindle index pulse to determine rotary speed and position of the material being threaded and advances the Z-axis the appropriate feed rate to generate the thread. The ability to track spindle speed and position allows threads to be cut in multiple passes, reducing tool loading.

                        The process is simple but torque limitations of the standard Sherline motor results in inconsistent spindle speeds during the threading process. You probably have noticed that spindle speed can change during normal lathe turning processes. MACH3 adjusts to the changes in speed due to tool loading, but when speed changes are pronounced, adjustments in Z-axis speed can result in an inconsistent thread. I have made various modifications to my Sherline lathe to improve threading, including replacing the standard 20-TPI leadscrew with a 5-TPI leadscrew, which allows threading a higher than normal spindle speeds. However, I think driving the spindle head with a proper sized stepper motor is all that one really needs to do. With my current system, I remove 0.005" per pass in free machining steel and even when cutting 20-TPI threads in .5" material, spindle speed remains constant through out the threading process.

                        More when the pictures are posted.

                        Regards,

                        Dan

                        --- In SherlineCNC@yahoogroups.com, Davide Ghelarducci <tuscanland@...> wrote:
                        >
                        > Hi Dan,
                        >  
                        > nice to hear back from you, I've wired everything correctely so far, just need to wait for the connectors to arrive and I'm all good to go.
                        > For now I'll go ahead with my plan about modifying the lathe, meaning I'll just use the threading attachment made by Sherline, driving the gears using the nema 34 stepper.
                        > I was under the impression that the 425 oz/in would have worked as well, but just to be on the safe side I've opted for the more powerful nema 34.
                        > I'm not sure how you are threading on the lathe, do you use the threading attachment in the same fashion that I plan to do, or do you thread using a mathematical formula combining spindle speed in conjunction with the appropriate feed rate on the z axis?
                        > I sure would be interested to see your pictures when you have time to upload them.
                        > Thanks for uploading the dxf files, I'll go look for them now.
                        > Best regards
                        > Davide
                        >




                        [Non-text portions of this message have been removed]
                      • jowhowho
                        I ve been using the standard Sherline lathe stepper spindle kit with LinuxCNC for single point threading. I program it like it is a fast rotary table. Since
                        Message 11 of 21 , Jul 22 3:41 PM
                          I've been using the standard Sherline lathe stepper spindle kit with LinuxCNC for single point threading. I program it like it is a fast rotary table. Since there is no feedback, if the spindle stepper motor stalls, the Z axis keeps going and can trash things. In free cutting brass and steel, I've been able to cut 3" 16tpi thread (with many passes). One of the things I like about this approach is that you can exactly control the lead-ins and lead-outs. I've also done some very nice knurling. I've gotten a bigger stepper motor than the standard little Sherline I've been using, but I haven't cut with it yet. There is also a three to one timing belt kit to replace the standard two to one kit.

                          -- Justin
                        • danieltbarber
                          Comments have been added to the photos. Regards, Dan
                          Message 12 of 21 , Jul 23 1:53 PM
                            Comments have been added to the photos.

                            Regards,

                            Dan

                            --- In SherlineCNC@yahoogroups.com, Douglas Vogt <dbvogt@...> wrote:
                            >
                            > Good information here for those that are considering adding a stepper to the spindle for threading. Would it be possible for you to insert a bit of text in your comments on setting up Mach to do this? There are several YouTube videos on running a spindle via stepper but not too much detail. Specifically, what has to be entered in the Ports & Pins for the spindle and what for the A axis?
                            >
                            >
                            >
                          • danieltbarber
                            Bruce, The last I read, MACH3 will use up to 4 index pulses per revolution, but the author of the software saw very little increase in accuracy when using more
                            Message 13 of 21 , Jul 23 2:15 PM
                              Bruce,

                              The last I read, MACH3 will use up to 4 index pulses per revolution, but the author of the software saw very little increase in accuracy when using more than 1 pulse per revolution. I think that he is correct, when the spindle is driven by a motor with enough torque to keep speeds consistent.

                              Like many people I use an optical sensor to generate the index pulse. In my case, I use a 20-slot encoder wheel, mounted to the spindle pulley. Using a "U" shaped optical sensor a pulse is generated each time a slot passes the sensor. Sensor output feeds into a PIC micro-controller, which is switch selectable to serve as either a tach, or to output a single square wave as an index pulse. The PIC calculates RPM based on the number of pulses occurring within a set period of time. The 20 slots makes the calculations using integer math fairly straight forward. When used as an index pulse generator, the PIC simply outputs a high or a low for 10 pulse counts.

                              Regards,

                              Dan

                              --- In SherlineCNC@yahoogroups.com, "bruce_e_layne" <yahoogroups@...> wrote:
                              >
                              > Neat project! Thanks for sharing.
                              >
                              > The last I heard, Mach uses one index pulse per spindle revolution, and as you mentioned, that's not really enough when the spindle is under load and the RPM varies. LinuxCNC uses a spindle encoder with one index pulse to initiate the threading operation and many pulses per revolution for much better control of spindle speed by frequently updating the current to the spindle motor to maintain a uniform angular velocity.
                              >
                              > Or, you could use a large stepper motor for the spindle as long as Mach 3 can be configured to use a stepper for the spindle motor when threading, and you don't load it so much that you lose any steps.
                              >
                              > I'm using LinuxCNC for my mini-lathe project. If I decide to use it for threading, I'll add a spindle encoder and see if I can get LinuxCNC to control the Sherline DC spindle motor.
                              >
                              >
                              >
                              > --- In SherlineCNC@yahoogroups.com, dtbarber@ wrote:
                              > >
                              > > Davide,
                              > >
                              > > I have created a photo album showing my approach for driving the spindle head with a stepper motor. Once approved by the moderator, I will add comments and more explanation.
                              > >
                              > > Regarding your question about how I am threading on the lathe, I use MACH3 and a single 60 degree lathe bit for CNC threading. There is a lot of information available about CNC threading with MACH3, but fundamentally, MACH3 uses a spindle index pulse to determine rotary speed and position of the material being threaded and advances the Z-axis the appropriate feed rate to generate the thread. The ability to track spindle speed and position allows threads to be cut in multiple passes, reducing tool loading.
                              > >
                              > > The process is simple but torque limitations of the standard Sherline motor results in inconsistent spindle speeds during the threading process. You probably have noticed that spindle speed can change during normal lathe turning processes. MACH3 adjusts to the changes in speed due to tool loading, but when speed changes are pronounced, adjustments in Z-axis speed can result in an inconsistent thread. I have made various modifications to my Sherline lathe to improve threading, including replacing the standard 20-TPI leadscrew with a 5-TPI leadscrew, which allows threading a higher than normal spindle speeds. However, I think driving the spindle head with a proper sized stepper motor is all that one really needs to do. With my current system, I remove 0.005" per pass in free machining steel and even when cutting 20-TPI threads in .5" material, spindle speed remains constant through out the threading process.
                              > >
                              > > More when the pictures are posted.
                              > >
                              > > Regards,
                              > >
                              > > Dan
                              >
                            • Andy Wander
                              Hi Dan: What you are doing sounds like it will work well, but it is NOT an Index Pulse. An Index Pulse occurs only once per revolution of the encoder or pulse
                              Message 14 of 21 , Jul 23 2:32 PM
                                Hi Dan:



                                What you are doing sounds like it will work well, but it is NOT an Index
                                Pulse.



                                An Index Pulse occurs only once per revolution of the encoder or pulse
                                generator, and is often used in combination with a multiple-pulse-per-rev
                                encoder to achieve better homing accuracy.



                                Andy Wander

                                _____

                                From: SherlineCNC@yahoogroups.com [mailto:SherlineCNC@yahoogroups.com] On
                                Behalf Of dtbarber@...
                                Sent: Tuesday, July 23, 2013 5:16 PM
                                To: SherlineCNC@yahoogroups.com
                                Subject: [SherlineCNC] Re: Connectors for Keling stepper driver - Threading





                                Bruce,

                                The last I read, MACH3 will use up to 4 index pulses per revolution, but the
                                author of the software saw very little increase in accuracy when using more
                                than 1 pulse per revolution. I think that he is correct, when the spindle is
                                driven by a motor with enough torque to keep speeds consistent.

                                Like many people I use an optical sensor to generate the index pulse. In my
                                case, I use a 20-slot encoder wheel, mounted to the spindle pulley. Using a
                                "U" shaped optical sensor a pulse is generated each time a slot passes the
                                sensor. Sensor output feeds into a PIC micro-controller, which is switch
                                selectable to serve as either a tach, or to output a single square wave as
                                an index pulse. The PIC calculates RPM based on the number of pulses
                                occurring within a set period of time. The 20 slots makes the calculations
                                using integer math fairly straight forward. When used as an index pulse
                                generator, the PIC simply outputs a high or a low for 10 pulse counts.

                                Regards,

                                Dan

                                --- In SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com> ,
                                "bruce_e_layne" <yahoogroups@...> wrote:
                                >
                                > Neat project! Thanks for sharing.
                                >
                                > The last I heard, Mach uses one index pulse per spindle revolution, and as
                                you mentioned, that's not really enough when the spindle is under load and
                                the RPM varies. LinuxCNC uses a spindle encoder with one index pulse to
                                initiate the threading operation and many pulses per revolution for much
                                better control of spindle speed by frequently updating the current to the
                                spindle motor to maintain a uniform angular velocity.
                                >
                                > Or, you could use a large stepper motor for the spindle as long as Mach 3
                                can be configured to use a stepper for the spindle motor when threading, and
                                you don't load it so much that you lose any steps.
                                >
                                > I'm using LinuxCNC for my mini-lathe project. If I decide to use it for
                                threading, I'll add a spindle encoder and see if I can get LinuxCNC to
                                control the Sherline DC spindle motor.
                                >
                                >
                                >
                                > --- In SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com>
                                , dtbarber@ wrote:
                                > >
                                > > Davide,
                                > >
                                > > I have created a photo album showing my approach for driving the spindle
                                head with a stepper motor. Once approved by the moderator, I will add
                                comments and more explanation.
                                > >
                                > > Regarding your question about how I am threading on the lathe, I use
                                MACH3 and a single 60 degree lathe bit for CNC threading. There is a lot of
                                information available about CNC threading with MACH3, but fundamentally,
                                MACH3 uses a spindle index pulse to determine rotary speed and position of
                                the material being threaded and advances the Z-axis the appropriate feed
                                rate to generate the thread. The ability to track spindle speed and position
                                allows threads to be cut in multiple passes, reducing tool loading.
                                > >
                                > > The process is simple but torque limitations of the standard Sherline
                                motor results in inconsistent spindle speeds during the threading process.
                                You probably have noticed that spindle speed can change during normal lathe
                                turning processes. MACH3 adjusts to the changes in speed due to tool
                                loading, but when speed changes are pronounced, adjustments in Z-axis speed
                                can result in an inconsistent thread. I have made various modifications to
                                my Sherline lathe to improve threading, including replacing the standard
                                20-TPI leadscrew with a 5-TPI leadscrew, which allows threading a higher
                                than normal spindle speeds. However, I think driving the spindle head with a
                                proper sized stepper motor is all that one really needs to do. With my
                                current system, I remove 0.005" per pass in free machining steel and even
                                when cutting 20-TPI threads in .5" material, spindle speed remains constant
                                through out the threading process.
                                > >
                                > > More when the pictures are posted.
                                > >
                                > > Regards,
                                > >
                                > > Dan
                                >





                                [Non-text portions of this message have been removed]
                              • danieltbarber
                                Andy, Thanks for your comments. Apparently, I was not clear in my explanation regarding my approach. The 20-pulse per revolution output from the optical
                                Message 15 of 21 , Jul 24 6:51 AM
                                  Andy,

                                  Thanks for your comments. Apparently, I was not clear in my explanation regarding my approach. The 20-pulse per revolution output from the optical sensor feeds into a PIC micro-controller which is user selectable to either function as a tach or as an index pulse generator. When functioning as a tach, the PIC counts the number of pulses that occur within a set period of time, calculates RPM, and then outputs the RPM to a four-digit, seven-segment LED display. When functioning as an index pulse generator, for each revolution, the PIC outputs a +5V signal when it first detects a pulse and holds that signal for a count of 10 pulses. It then pulls the pin low for the next 10 pulses. This single pulse per revolution square wave output feeds into MACH3 for determining spindle speed and location for threading. I have been using this system for at least 5 years and works perfectly.

                                  Regards,

                                  Dan





                                  --- In SherlineCNC@yahoogroups.com, "Andy Wander" <andywander@...> wrote:
                                  >
                                  > Hi Dan:
                                  >
                                  >
                                  >
                                  > What you are doing sounds like it will work well, but it is NOT an Index
                                  > Pulse.
                                  >
                                  >
                                  >
                                  > An Index Pulse occurs only once per revolution of the encoder or pulse
                                  > generator, and is often used in combination with a multiple-pulse-per-rev
                                  > encoder to achieve better homing accuracy.
                                  >
                                  >
                                  >
                                  > Andy Wander
                                  >
                                  > _____
                                  >
                                  > From: SherlineCNC@yahoogroups.com [mailto:SherlineCNC@yahoogroups.com] On
                                  > Behalf Of dtbarber@...
                                  > Sent: Tuesday, July 23, 2013 5:16 PM
                                  > To: SherlineCNC@yahoogroups.com
                                  > Subject: [SherlineCNC] Re: Connectors for Keling stepper driver - Threading
                                  >
                                  >
                                  >
                                  >
                                  >
                                  > Bruce,
                                  >
                                  > The last I read, MACH3 will use up to 4 index pulses per revolution, but the
                                  > author of the software saw very little increase in accuracy when using more
                                  > than 1 pulse per revolution. I think that he is correct, when the spindle is
                                  > driven by a motor with enough torque to keep speeds consistent.
                                  >
                                  > Like many people I use an optical sensor to generate the index pulse. In my
                                  > case, I use a 20-slot encoder wheel, mounted to the spindle pulley. Using a
                                  > "U" shaped optical sensor a pulse is generated each time a slot passes the
                                  > sensor. Sensor output feeds into a PIC micro-controller, which is switch
                                  > selectable to serve as either a tach, or to output a single square wave as
                                  > an index pulse. The PIC calculates RPM based on the number of pulses
                                  > occurring within a set period of time. The 20 slots makes the calculations
                                  > using integer math fairly straight forward. When used as an index pulse
                                  > generator, the PIC simply outputs a high or a low for 10 pulse counts.
                                  >
                                  > Regards,
                                  >
                                  > Dan
                                  >
                                  > --- In SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com> ,
                                  > "bruce_e_layne" <yahoogroups@> wrote:
                                  > >
                                  > > Neat project! Thanks for sharing.
                                  > >
                                  > > The last I heard, Mach uses one index pulse per spindle revolution, and as
                                  > you mentioned, that's not really enough when the spindle is under load and
                                  > the RPM varies. LinuxCNC uses a spindle encoder with one index pulse to
                                  > initiate the threading operation and many pulses per revolution for much
                                  > better control of spindle speed by frequently updating the current to the
                                  > spindle motor to maintain a uniform angular velocity.
                                  > >
                                  > > Or, you could use a large stepper motor for the spindle as long as Mach 3
                                  > can be configured to use a stepper for the spindle motor when threading, and
                                  > you don't load it so much that you lose any steps.
                                  > >
                                  > > I'm using LinuxCNC for my mini-lathe project. If I decide to use it for
                                  > threading, I'll add a spindle encoder and see if I can get LinuxCNC to
                                  > control the Sherline DC spindle motor.
                                  > >
                                  > >
                                  > >
                                  > > --- In SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com>
                                  > , dtbarber@ wrote:
                                  > > >
                                  > > > Davide,
                                  > > >
                                  > > > I have created a photo album showing my approach for driving the spindle
                                  > head with a stepper motor. Once approved by the moderator, I will add
                                  > comments and more explanation.
                                  > > >
                                  > > > Regarding your question about how I am threading on the lathe, I use
                                  > MACH3 and a single 60 degree lathe bit for CNC threading. There is a lot of
                                  > information available about CNC threading with MACH3, but fundamentally,
                                  > MACH3 uses a spindle index pulse to determine rotary speed and position of
                                  > the material being threaded and advances the Z-axis the appropriate feed
                                  > rate to generate the thread. The ability to track spindle speed and position
                                  > allows threads to be cut in multiple passes, reducing tool loading.
                                  > > >
                                  > > > The process is simple but torque limitations of the standard Sherline
                                  > motor results in inconsistent spindle speeds during the threading process.
                                  > You probably have noticed that spindle speed can change during normal lathe
                                  > turning processes. MACH3 adjusts to the changes in speed due to tool
                                  > loading, but when speed changes are pronounced, adjustments in Z-axis speed
                                  > can result in an inconsistent thread. I have made various modifications to
                                  > my Sherline lathe to improve threading, including replacing the standard
                                  > 20-TPI leadscrew with a 5-TPI leadscrew, which allows threading a higher
                                  > than normal spindle speeds. However, I think driving the spindle head with a
                                  > proper sized stepper motor is all that one really needs to do. With my
                                  > current system, I remove 0.005" per pass in free machining steel and even
                                  > when cutting 20-TPI threads in .5" material, spindle speed remains constant
                                  > through out the threading process.
                                  > > >
                                  > > > More when the pictures are posted.
                                  > > >
                                  > > > Regards,
                                  > > >
                                  > > > Dan
                                  > >
                                  >
                                  >
                                  >
                                  >
                                  >
                                  > [Non-text portions of this message have been removed]
                                  >
                                • Andy Wander
                                  Ah, yes that makes it an Index pulse. I don t believe Mach cares about the relative lengths of the ON and FF portions of the pulse, though. thanks, Andy Wander
                                  Message 16 of 21 , Jul 24 7:03 AM
                                    Ah, yes that makes it an Index pulse.



                                    I don't believe Mach cares about the relative lengths of the ON and FF
                                    portions of the pulse, though.



                                    thanks,



                                    Andy Wander

                                    _____

                                    From: SherlineCNC@yahoogroups.com [mailto:SherlineCNC@yahoogroups.com] On
                                    Behalf Of danieltbarber
                                    Sent: Wednesday, July 24, 2013 9:51 AM
                                    To: SherlineCNC@yahoogroups.com
                                    Subject: [SherlineCNC] Re: Connectors for Keling stepper driver - Threading





                                    Andy,

                                    Thanks for your comments. Apparently, I was not clear in my explanation
                                    regarding my approach. The 20-pulse per revolution output from the optical
                                    sensor feeds into a PIC micro-controller which is user selectable to either
                                    function as a tach or as an index pulse generator. When functioning as a
                                    tach, the PIC counts the number of pulses that occur within a set period of
                                    time, calculates RPM, and then outputs the RPM to a four-digit,
                                    seven-segment LED display. When functioning as an index pulse generator, for
                                    each revolution, the PIC outputs a +5V signal when it first detects a pulse
                                    and holds that signal for a count of 10 pulses. It then pulls the pin low
                                    for the next 10 pulses. This single pulse per revolution square wave output
                                    feeds into MACH3 for determining spindle speed and location for threading. I
                                    have been using this system for at least 5 years and works perfectly.

                                    Regards,

                                    Dan

                                    --- In SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com> ,
                                    "Andy Wander" <andywander@...> wrote:
                                    >
                                    > Hi Dan:
                                    >
                                    >
                                    >
                                    > What you are doing sounds like it will work well, but it is NOT an Index
                                    > Pulse.
                                    >
                                    >
                                    >
                                    > An Index Pulse occurs only once per revolution of the encoder or pulse
                                    > generator, and is often used in combination with a multiple-pulse-per-rev
                                    > encoder to achieve better homing accuracy.
                                    >
                                    >
                                    >
                                    > Andy Wander
                                    >
                                    > _____
                                    >
                                    > From: SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com>
                                    [mailto:SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com> ]
                                    On
                                    > Behalf Of dtbarber@...
                                    > Sent: Tuesday, July 23, 2013 5:16 PM
                                    > To: SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com>
                                    > Subject: [SherlineCNC] Re: Connectors for Keling stepper driver -
                                    Threading
                                    >
                                    >
                                    >
                                    >
                                    >
                                    > Bruce,
                                    >
                                    > The last I read, MACH3 will use up to 4 index pulses per revolution, but
                                    the
                                    > author of the software saw very little increase in accuracy when using
                                    more
                                    > than 1 pulse per revolution. I think that he is correct, when the spindle
                                    is
                                    > driven by a motor with enough torque to keep speeds consistent.
                                    >
                                    > Like many people I use an optical sensor to generate the index pulse. In
                                    my
                                    > case, I use a 20-slot encoder wheel, mounted to the spindle pulley. Using
                                    a
                                    > "U" shaped optical sensor a pulse is generated each time a slot passes the
                                    > sensor. Sensor output feeds into a PIC micro-controller, which is switch
                                    > selectable to serve as either a tach, or to output a single square wave as
                                    > an index pulse. The PIC calculates RPM based on the number of pulses
                                    > occurring within a set period of time. The 20 slots makes the calculations
                                    > using integer math fairly straight forward. When used as an index pulse
                                    > generator, the PIC simply outputs a high or a low for 10 pulse counts.
                                    >
                                    > Regards,
                                    >
                                    > Dan
                                    >
                                    > --- In SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com>
                                    <mailto:SherlineCNC%40yahoogroups.com> ,
                                    > "bruce_e_layne" <yahoogroups@> wrote:
                                    > >
                                    > > Neat project! Thanks for sharing.
                                    > >
                                    > > The last I heard, Mach uses one index pulse per spindle revolution, and
                                    as
                                    > you mentioned, that's not really enough when the spindle is under load and
                                    > the RPM varies. LinuxCNC uses a spindle encoder with one index pulse to
                                    > initiate the threading operation and many pulses per revolution for much
                                    > better control of spindle speed by frequently updating the current to the
                                    > spindle motor to maintain a uniform angular velocity.
                                    > >
                                    > > Or, you could use a large stepper motor for the spindle as long as Mach
                                    3
                                    > can be configured to use a stepper for the spindle motor when threading,
                                    and
                                    > you don't load it so much that you lose any steps.
                                    > >
                                    > > I'm using LinuxCNC for my mini-lathe project. If I decide to use it for
                                    > threading, I'll add a spindle encoder and see if I can get LinuxCNC to
                                    > control the Sherline DC spindle motor.
                                    > >
                                    > >
                                    > >
                                    > > --- In SherlineCNC@yahoogroups.com
                                    <mailto:SherlineCNC%40yahoogroups.com>
                                    <mailto:SherlineCNC%40yahoogroups.com>
                                    > , dtbarber@ wrote:
                                    > > >
                                    > > > Davide,
                                    > > >
                                    > > > I have created a photo album showing my approach for driving the
                                    spindle
                                    > head with a stepper motor. Once approved by the moderator, I will add
                                    > comments and more explanation.
                                    > > >
                                    > > > Regarding your question about how I am threading on the lathe, I use
                                    > MACH3 and a single 60 degree lathe bit for CNC threading. There is a lot
                                    of
                                    > information available about CNC threading with MACH3, but fundamentally,
                                    > MACH3 uses a spindle index pulse to determine rotary speed and position of
                                    > the material being threaded and advances the Z-axis the appropriate feed
                                    > rate to generate the thread. The ability to track spindle speed and
                                    position
                                    > allows threads to be cut in multiple passes, reducing tool loading.
                                    > > >
                                    > > > The process is simple but torque limitations of the standard Sherline
                                    > motor results in inconsistent spindle speeds during the threading process.
                                    > You probably have noticed that spindle speed can change during normal
                                    lathe
                                    > turning processes. MACH3 adjusts to the changes in speed due to tool
                                    > loading, but when speed changes are pronounced, adjustments in Z-axis
                                    speed
                                    > can result in an inconsistent thread. I have made various modifications to
                                    > my Sherline lathe to improve threading, including replacing the standard
                                    > 20-TPI leadscrew with a 5-TPI leadscrew, which allows threading a higher
                                    > than normal spindle speeds. However, I think driving the spindle head with
                                    a
                                    > proper sized stepper motor is all that one really needs to do. With my
                                    > current system, I remove 0.005" per pass in free machining steel and even
                                    > when cutting 20-TPI threads in .5" material, spindle speed remains
                                    constant
                                    > through out the threading process.
                                    > > >
                                    > > > More when the pictures are posted.
                                    > > >
                                    > > > Regards,
                                    > > >
                                    > > > Dan
                                    > >
                                    >
                                    >
                                    >
                                    >
                                    >
                                    > [Non-text portions of this message have been removed]
                                    >





                                    [Non-text portions of this message have been removed]
                                  • Sullivan, John
                                    Dan, What you described sounds rather similar to how Sherline s DRO works. It has long left me curious as to how it knows which direction the toothed wheel is
                                    Message 17 of 21 , Jul 24 9:17 AM
                                      Dan,

                                      What you described sounds rather similar to how Sherline's DRO works.
                                      It has long left me curious as to how it knows which direction the toothed wheel is going?

                                      Would any of you be able to explain this small mystery to me?

                                      Thank you,

                                      John G. Sullivan
                                      Austin, Texas
                                      512-340-6078

                                      ________________________________________________________________________
                                      1b. Re: Connectors for Keling stepper driver - Threading
                                      Posted by: dtbarber@... danieltbarber
                                      Date: Tue Jul 23, 2013 2:15 pm ((PDT))

                                      Bruce,

                                      The last I read, MACH3 will use up to 4 index pulses per revolution, but the author of the software saw very little increase in accuracy when using more than 1 pulse per revolution. I think that he is correct, when the spindle is driven by a motor with enough torque to keep speeds consistent.

                                      Like many people I use an optical sensor to generate the index pulse. In my case, I use a 20-slot encoder wheel, mounted to the spindle pulley. Using a "U" shaped optical sensor a pulse is generated each time a slot passes the sensor. Sensor output feeds into a PIC micro-controller, which is switch selectable to serve as either a tach, or to output a single square wave as an index pulse. The PIC calculates RPM based on the number of pulses occurring within a set period of time. The 20 slots makes the calculations using integer math fairly straight forward. When used as an index pulse generator, the PIC simply outputs a high or a low for 10 pulse counts.

                                      Regards,

                                      Dan

                                      --- In SherlineCNC@yahoogroups.com, "bruce_e_layne" <yahoogroups@...> wrote:
                                      >
                                      > Neat project! Thanks for sharing.
                                      >
                                      > The last I heard, Mach uses one index pulse per spindle revolution, and as you mentioned, that's not really enough when the spindle is under load and the RPM varies. LinuxCNC uses a spindle encoder with one index pulse to initiate the threading operation and many pulses per revolution for much better control of spindle speed by frequently updating the current to the spindle motor to maintain a uniform angular velocity.
                                      >
                                      > Or, you could use a large stepper motor for the spindle as long as Mach 3 can be configured to use a stepper for the spindle motor when threading, and you don't load it so much that you lose any steps.
                                      >
                                      > I'm using LinuxCNC for my mini-lathe project. If I decide to use it for threading, I'll add a spindle encoder and see if I can get LinuxCNC to control the Sherline DC spindle motor.
                                      >
                                      >
                                      >
                                      > --- In SherlineCNC@yahoogroups.com, dtbarber@ wrote:
                                      > >
                                      > > Davide,
                                      > >
                                      > > I have created a photo album showing my approach for driving the spindle head with a stepper motor. Once approved by the moderator, I will add comments and more explanation.
                                      > >
                                      > > Regarding your question about how I am threading on the lathe, I use MACH3 and a single 60 degree lathe bit for CNC threading. There is a lot of information available about CNC threading with MACH3, but fundamentally, MACH3 uses a spindle index pulse to determine rotary speed and position of the material being threaded and advances the Z-axis the appropriate feed rate to generate the thread. The ability to track spindle speed and position allows threads to be cut in multiple passes, reducing tool loading.
                                      > >
                                      > > The process is simple but torque limitations of the standard Sherline motor results in inconsistent spindle speeds during the threading process. You probably have noticed that spindle speed can change during normal lathe turning processes. MACH3 adjusts to the changes in speed due to tool loading, but when speed changes are pronounced, adjustments in Z-axis speed can result in an inconsistent thread. I have made various modifications to my Sherline lathe to improve threading, including replacing the standard 20-TPI leadscrew with a 5-TPI leadscrew, which allows threading a higher than normal spindle speeds. However, I think driving the spindle head with a proper sized stepper motor is all that one really needs to do. With my current system, I remove 0.005" per pass in free machining steel and even when cutting 20-TPI threads in .5" material, spindle speed remains constant through out the threading process.
                                      > >
                                      > > More when the pictures are posted.
                                      > >
                                      > > Regards,
                                      > >
                                      > > Dan
                                    • Andy Wander
                                      John: Most directional devices of this sort use what is called a Quadrature Encoder. Look it up and you will see how the use of 2 sensors can indicate
                                      Message 18 of 21 , Jul 24 9:41 AM
                                        John:



                                        Most directional devices of this sort use what is called a Quadrature
                                        Encoder. Look it up and you will see how the use of 2 sensors can indicate
                                        direction.



                                        Andy Wander

                                        _____

                                        From: SherlineCNC@yahoogroups.com [mailto:SherlineCNC@yahoogroups.com] On
                                        Behalf Of Sullivan, John
                                        Sent: Wednesday, July 24, 2013 12:18 PM
                                        To: SherlineCNC@yahoogroups.com
                                        Subject: [SherlineCNC] Re: Connectors for Keling stepper driver - Threading





                                        Dan,

                                        What you described sounds rather similar to how Sherline's DRO works.
                                        It has long left me curious as to how it knows which direction the toothed
                                        wheel is going?

                                        Would any of you be able to explain this small mystery to me?

                                        Thank you,

                                        John G. Sullivan
                                        Austin, Texas
                                        512-340-6078

                                        __________________________________________________________
                                        1b. Re: Connectors for Keling stepper driver - Threading
                                        Posted by: dtbarber@... <mailto:dtbarber%40sti.net> danieltbarber
                                        Date: Tue Jul 23, 2013 2:15 pm ((PDT))

                                        Bruce,

                                        The last I read, MACH3 will use up to 4 index pulses per revolution, but the
                                        author of the software saw very little increase in accuracy when using more
                                        than 1 pulse per revolution. I think that he is correct, when the spindle is
                                        driven by a motor with enough torque to keep speeds consistent.

                                        Like many people I use an optical sensor to generate the index pulse. In my
                                        case, I use a 20-slot encoder wheel, mounted to the spindle pulley. Using a
                                        "U" shaped optical sensor a pulse is generated each time a slot passes the
                                        sensor. Sensor output feeds into a PIC micro-controller, which is switch
                                        selectable to serve as either a tach, or to output a single square wave as
                                        an index pulse. The PIC calculates RPM based on the number of pulses
                                        occurring within a set period of time. The 20 slots makes the calculations
                                        using integer math fairly straight forward. When used as an index pulse
                                        generator, the PIC simply outputs a high or a low for 10 pulse counts.

                                        Regards,

                                        Dan

                                        --- In SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com> ,
                                        "bruce_e_layne" <yahoogroups@...> wrote:
                                        >
                                        > Neat project! Thanks for sharing.
                                        >
                                        > The last I heard, Mach uses one index pulse per spindle revolution, and as
                                        you mentioned, that's not really enough when the spindle is under load and
                                        the RPM varies. LinuxCNC uses a spindle encoder with one index pulse to
                                        initiate the threading operation and many pulses per revolution for much
                                        better control of spindle speed by frequently updating the current to the
                                        spindle motor to maintain a uniform angular velocity.
                                        >
                                        > Or, you could use a large stepper motor for the spindle as long as Mach 3
                                        can be configured to use a stepper for the spindle motor when threading, and
                                        you don't load it so much that you lose any steps.
                                        >
                                        > I'm using LinuxCNC for my mini-lathe project. If I decide to use it for
                                        threading, I'll add a spindle encoder and see if I can get LinuxCNC to
                                        control the Sherline DC spindle motor.
                                        >
                                        >
                                        >
                                        > --- In SherlineCNC@yahoogroups.com <mailto:SherlineCNC%40yahoogroups.com>
                                        , dtbarber@ wrote:
                                        > >
                                        > > Davide,
                                        > >
                                        > > I have created a photo album showing my approach for driving the spindle
                                        head with a stepper motor. Once approved by the moderator, I will add
                                        comments and more explanation.
                                        > >
                                        > > Regarding your question about how I am threading on the lathe, I use
                                        MACH3 and a single 60 degree lathe bit for CNC threading. There is a lot of
                                        information available about CNC threading with MACH3, but fundamentally,
                                        MACH3 uses a spindle index pulse to determine rotary speed and position of
                                        the material being threaded and advances the Z-axis the appropriate feed
                                        rate to generate the thread. The ability to track spindle speed and position
                                        allows threads to be cut in multiple passes, reducing tool loading.
                                        > >
                                        > > The process is simple but torque limitations of the standard Sherline
                                        motor results in inconsistent spindle speeds during the threading process.
                                        You probably have noticed that spindle speed can change during normal lathe
                                        turning processes. MACH3 adjusts to the changes in speed due to tool
                                        loading, but when speed changes are pronounced, adjustments in Z-axis speed
                                        can result in an inconsistent thread. I have made various modifications to
                                        my Sherline lathe to improve threading, including replacing the standard
                                        20-TPI leadscrew with a 5-TPI leadscrew, which allows threading a higher
                                        than normal spindle speeds. However, I think driving the spindle head with a
                                        proper sized stepper motor is all that one really needs to do. With my
                                        current system, I remove 0.005" per pass in free machining steel and even
                                        when cutting 20-TPI threads in .5" material, spindle speed remains constant
                                        through out the threading process.
                                        > >
                                        > > More when the pictures are posted.
                                        > >
                                        > > Regards,
                                        > >
                                        > > Dan





                                        [Non-text portions of this message have been removed]
                                      • KM6VV
                                        Sounds like a nice system Dan. Did you buy/build it? Alan KM6VV ... The 20-pulse per revolution output from the optical sensor feeds into a PIC
                                        Message 19 of 21 , Jul 24 11:36 AM
                                          Sounds like a nice system Dan. Did you buy/build it?

                                          Alan KM6VV

                                          On 7/24/2013 6:51 AM, danieltbarber wrote:
                                          > Andy,
                                          >
                                          > Thanks for your comments. Apparently, I was not clear in my explanation regarding my approach.

                                          The 20-pulse per revolution output from the optical sensor feeds into a
                                          PIC micro-controller which is user

                                          selectable to either function as a tach or as an index pulse generator.
                                          When functioning as a tach, the

                                          PIC counts the number of pulses that occur within a set period of time,
                                          calculates RPM, and then outputs

                                          the RPM to a four-digit, seven-segment LED display. When functioning as
                                          an index pulse generator, for

                                          each revolution, the PIC outputs a +5V signal when it first detects a
                                          pulse and holds that signal for a

                                          count of 10 pulses. It then pulls the pin low for the next 10 pulses.
                                          This single pulse per revolution

                                          square wave output feeds into MACH3 for determining spindle speed and
                                          location for threading. I have

                                          been using this system for at least 5 years and works perfectly.
                                          >
                                          > Regards,
                                          >
                                          > Dan
                                          >
                                        • danieltbarber
                                          Alan, Thanks, the system is all shop built and the design works well enough that I have stopped working on it. The only unresolved issue is that when mounted
                                          Message 20 of 21 , Jul 24 1:04 PM
                                            Alan,

                                            Thanks, the system is all shop built and the design works well enough that I have stopped working on it. The only unresolved issue is that when mounted in the same enclosure as a Gecko G540 controller and powered by the same power supply, the electrical noise can cause the RPMs to be erratic. Interestingly, I have two controllers, which are for practical purposes the same, however, only one has the problem. This could likely be corrected by adding a few strategic filtering caps, but it was easier to just power the tach from a wall-wart

                                            Regards,

                                            Dan





                                            --- In SherlineCNC@yahoogroups.com, KM6VV <KM6VV@...> wrote:
                                            >
                                            > Sounds like a nice system Dan. Did you buy/build it?
                                            >
                                            > Alan KM6VV
                                          • tuscanland
                                            Hi to all, I m done assembling the lathe, the only thing I m missing is the correct preload nut for the crosslide lead screw, it should be coming in next
                                            Message 21 of 21 , Aug 24, 2013
                                              Hi to all, I'm done assembling the lathe, the only thing I'm missing is the correct preload nut for the crosslide lead screw, it should be coming in next week. I was able to test the electronics and everything seems to work ok, I posted a photo of what the lathe looks like at this point, but I'm confident that it will be completed by the end of the month, and at that point I'll post a few more.

                                              --- In SherlineCNC@yahoogroups.com, dtbarber@... wrote:
                                              >
                                              > Davide,
                                              >
                                              > I have created a photo album showing my approach for driving the spindle head with a stepper motor. Once approved by the moderator, I will add comments and more explanation.
                                              >
                                              > Regarding your question about how I am threading on the lathe, I use MACH3 and a single 60 degree lathe bit for CNC threading. There is a lot of information available about CNC threading with MACH3, but fundamentally, MACH3 uses a spindle index pulse to determine rotary speed and position of the material being threaded and advances the Z-axis the appropriate feed rate to generate the thread. The ability to track spindle speed and position allows threads to be cut in multiple passes, reducing tool loading.
                                              >
                                              > The process is simple but torque limitations of the standard Sherline motor results in inconsistent spindle speeds during the threading process. You probably have noticed that spindle speed can change during normal lathe turning processes. MACH3 adjusts to the changes in speed due to tool loading, but when speed changes are pronounced, adjustments in Z-axis speed can result in an inconsistent thread. I have made various modifications to my Sherline lathe to improve threading, including replacing the standard 20-TPI leadscrew with a 5-TPI leadscrew, which allows threading a higher than normal spindle speeds. However, I think driving the spindle head with a proper sized stepper motor is all that one really needs to do. With my current system, I remove 0.005" per pass in free machining steel and even when cutting 20-TPI threads in .5" material, spindle speed remains constant through out the threading process.
                                              >
                                              > More when the pictures are posted.
                                              >
                                              > Regards,
                                              >
                                              > Dan
                                              >
                                              > --- In SherlineCNC@yahoogroups.com, Davide Ghelarducci <tuscanland@> wrote:
                                              > >
                                              > > Hi Dan,
                                              > >  
                                              > > nice to hear back from you, I've wired everything correctely so far, just need to wait for the connectors to arrive and I'm all good to go.
                                              > > For now I'll go ahead with my plan about modifying the lathe, meaning I'll just use the threading attachment made by Sherline, driving the gears using the nema 34 stepper.
                                              > > I was under the impression that the 425 oz/in would have worked as well, but just to be on the safe side I've opted for the more powerful nema 34.
                                              > > I'm not sure how you are threading on the lathe, do you use the threading attachment in the same fashion that I plan to do, or do you thread using a mathematical formula combining spindle speed in conjunction with the appropriate feed rate on the z axis?
                                              > > I sure would be interested to see your pictures when you have time to upload them.
                                              > > Thanks for uploading the dxf files, I'll go look for them now.
                                              > > Best regards
                                              > > Davide
                                              > >
                                              >
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