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Re: [SherlineCNC] Connectors for Keling stepper driver

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  • Manfred Vormbaum
    If you double click on this link: KL11080Wiring on the page
    Message 1 of 21 , Jul 17, 2013
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      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 2 of 21 , Jul 18, 2013
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        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 3 of 21 , Jul 18, 2013
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          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 4 of 21 , Jul 18, 2013
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            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 5 of 21 , Jul 19, 2013
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              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 6 of 21 , Jul 21, 2013
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                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 7 of 21 , Jul 22, 2013
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                  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 8 of 21 , Jul 22, 2013
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                    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 9 of 21 , Jul 22, 2013
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                      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 10 of 21 , Jul 22, 2013
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                        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 11 of 21 , Jul 23, 2013
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                          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 12 of 21 , Jul 23, 2013
                          • 0 Attachment
                            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 13 of 21 , Jul 23, 2013
                            • 0 Attachment
                              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 14 of 21 , Jul 24, 2013
                              • 0 Attachment
                                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 15 of 21 , Jul 24, 2013
                                • 0 Attachment
                                  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 16 of 21 , Jul 24, 2013
                                  • 0 Attachment
                                    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 17 of 21 , Jul 24, 2013
                                    • 0 Attachment
                                      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 18 of 21 , Jul 24, 2013
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                                        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 19 of 21 , Jul 24, 2013
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                                          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 20 of 21 , Aug 24, 2013
                                          • 0 Attachment
                                            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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