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Re: [SherlineCNC] Re: How do you tap holes?

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  • Scott Meyer
    A thread mill and a tap are designed entirely differently. The teeth on a tap are on a helix. No tooth on the tap lines up with another tooth. So if you used a
    Message 1 of 10 , Nov 1, 2011
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      A thread mill and a tap are designed entirely differently.

      The teeth on a tap are on a helix. No tooth on the tap lines up with
      another tooth. So if you used a tap as a end mill, and milled around a
      shaft in a circle (no Z movement), you would have a smaller diameter shaft.

      The teeth on a thread mill do line up. If you milled around a shaft on a
      circle, no Z movement, you would have a shaft with several V cuts into it.

      The only way you could use a tap as a thread mill is if you moved the
      tap in Z 1 pitch per revolution. So, if you were doing 1"- 8 threads,
      you would move in Z .125 for every revolution of the spindle. You would
      also have to move 360 degrees around the shaft, per revolution. Pretty
      hard on the tap and you would get pretty crappy threads.

      With a thread mill, RPM and feed rate are irrelevant to the formation of
      the thread. As long as the machine is moving in a true helix, you'll get
      a good thread, regardless of feed or RPM.

      Scott Meyer


      On 11/1/2011 2:54 AM, sherlinenoob wrote:
      > Why cant you use it natively but have to get rid of all of them except one cutting edge? If your helical motion is correct with the right feed/rpm can you just use a native manual tap to machine thread with all its teeth? I dont know, I guess you cant guarentee rpm or if there is slight error the other teeth may pass through material and cut off extra material?
      >
      > --- In SherlineCNC@yahoogroups.com, "RCGuy"<calvino.rc@...> wrote:
      >> $10 tap vs $100 thread mill... tap any day of the week here! Ok well you can't use a tap as it is out of the box. You have to grind all the teeth off except for one row, and relieve the back, like this guy did. ..
      >>
      >> http://www.youtube.com/watch?v=-J_Xrkrs1Xc
      >>
      >> In all reality it isn't that hard to thread mill, its just making sure the machine is traveling in a helical interpolation at the right numbers and your good! I have personally seen on a Fadal VMC thread milling done with a VERY tiny {about size of a pencil eraser on a pencil?} thread mill creating precise taps in a piece of steel as a thread gauge.
      >>
      >> --- In SherlineCNC@yahoogroups.com, "sherlinenoob"<ly_smell@> wrote:
      >>> Do you need special cutters per se? Have you tried the el-cheapo standard manual taps (not really el-cheapo since they arnt really cheap) as a thread cutter to do helical milling?
      >>>
      >>> I havent tried any of this of course but there is some cutting action capability right as a cutter. Maybe can do many passes?
      >>>
      >>> --- In SherlineCNC@yahoogroups.com, "Eric"<buckeyevs@> wrote:
      >>>> Helical milling with a thread form cutter is an option for a small enough cutter and large enough hole for those of us with plain old DC spindle motors. The trouble with this is that those cutters are usually pretty expensive. I made the purchase and it beats the heck out of single point threading on the lathe.
      >>>>
      >>>> Eric
      >>>>
      >>>> --- In SherlineCNC@yahoogroups.com, "sherlinenoob"<ly_smell@> wrote:
      >>>>> Call me a noob but how do you tap holes in general with a CNC and also techniques with a sherline?
      >>>>>
      >>>>> I know you can manually press one in or have the fancier machines. In terms of CNC I know they also have similar tapping heads you can fit in. Is there other ways? Other fancier CNC machines with stepper or servo controlled spindles can plunge in and then unwind on the way out. But how is it done then on one directional DC spindles?
      >>>>>
      >>>>> Like getting the right tool with the right pitch cutting edges that is smaller than a bored hole and then helical entry into the hole sort of thing?
      >>>>>
      >>>>> Any techniques for the sherline?
      >>>>>
      >
      >
      >
      > ------------------------------------
      >
      > Yahoo! Groups Links
      >
      >
      >
    • Andy Wander
      I have heard of folks using an old tap to mill threads by removing(with a grinder) all but one tooth from the tap. ... [Non-text portions of this message have
      Message 2 of 10 , Nov 1, 2011
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        I have heard of folks using an old tap to mill threads by removing(with a
        grinder) all but one tooth from the tap.

        On Tue, Nov 1, 2011 at 8:32 AM, Scott Meyer <baldysm@...> wrote:

        > A thread mill and a tap are designed entirely differently.
        >
        > The teeth on a tap are on a helix. No tooth on the tap lines up with
        > another tooth. So if you used a tap as a end mill, and milled around a
        > shaft in a circle (no Z movement), you would have a smaller diameter shaft.
        >
        > The teeth on a thread mill do line up. If you milled around a shaft on a
        > circle, no Z movement, you would have a shaft with several V cuts into it.
        >
        > The only way you could use a tap as a thread mill is if you moved the
        > tap in Z 1 pitch per revolution. So, if you were doing 1"- 8 threads,
        > you would move in Z .125 for every revolution of the spindle. You would
        > also have to move 360 degrees around the shaft, per revolution. Pretty
        > hard on the tap and you would get pretty crappy threads.
        >
        > With a thread mill, RPM and feed rate are irrelevant to the formation of
        > the thread. As long as the machine is moving in a true helix, you'll get
        > a good thread, regardless of feed or RPM.
        >
        > Scott Meyer
        >
        >
        > On 11/1/2011 2:54 AM, sherlinenoob wrote:
        > > Why cant you use it natively but have to get rid of all of them except
        > one cutting edge? If your helical motion is correct with the right feed/rpm
        > can you just use a native manual tap to machine thread with all its teeth?
        > I dont know, I guess you cant guarentee rpm or if there is slight error the
        > other teeth may pass through material and cut off extra material?
        > >
        > > --- In SherlineCNC@yahoogroups.com, "RCGuy"<calvino.rc@...> wrote:
        > >> $10 tap vs $100 thread mill... tap any day of the week here! Ok well
        > you can't use a tap as it is out of the box. You have to grind all the
        > teeth off except for one row, and relieve the back, like this guy did. ..
        > >>
        > >> http://www.youtube.com/watch?v=-J_Xrkrs1Xc
        > >>
        > >> In all reality it isn't that hard to thread mill, its just making sure
        > the machine is traveling in a helical interpolation at the right numbers
        > and your good! I have personally seen on a Fadal VMC thread milling done
        > with a VERY tiny {about size of a pencil eraser on a pencil?} thread mill
        > creating precise taps in a piece of steel as a thread gauge.
        > >>
        > >> --- In SherlineCNC@yahoogroups.com, "sherlinenoob"<ly_smell@> wrote:
        > >>> Do you need special cutters per se? Have you tried the el-cheapo
        > standard manual taps (not really el-cheapo since they arnt really cheap) as
        > a thread cutter to do helical milling?
        > >>>
        > >>> I havent tried any of this of course but there is some cutting action
        > capability right as a cutter. Maybe can do many passes?
        > >>>
        > >>> --- In SherlineCNC@yahoogroups.com, "Eric"<buckeyevs@> wrote:
        > >>>> Helical milling with a thread form cutter is an option for a small
        > enough cutter and large enough hole for those of us with plain old DC
        > spindle motors. The trouble with this is that those cutters are usually
        > pretty expensive. I made the purchase and it beats the heck out of single
        > point threading on the lathe.
        > >>>>
        > >>>> Eric
        > >>>>
        > >>>> --- In SherlineCNC@yahoogroups.com, "sherlinenoob"<ly_smell@> wrote:
        > >>>>> Call me a noob but how do you tap holes in general with a CNC and
        > also techniques with a sherline?
        > >>>>>
        > >>>>> I know you can manually press one in or have the fancier machines.
        > In terms of CNC I know they also have similar tapping heads you can fit in.
        > Is there other ways? Other fancier CNC machines with stepper or servo
        > controlled spindles can plunge in and then unwind on the way out. But how
        > is it done then on one directional DC spindles?
        > >>>>>
        > >>>>> Like getting the right tool with the right pitch cutting edges that
        > is smaller than a bored hole and then helical entry into the hole sort of
        > thing?
        > >>>>>
        > >>>>> Any techniques for the sherline?
        > >>>>>
        > >
        > >
        > >
        > > ------------------------------------
        > >
        > > Yahoo! Groups Links
        > >
        > >
        > >
        >
        >
        > ------------------------------------
        >
        > Yahoo! Groups Links
        >
        >
        >
        >


        [Non-text portions of this message have been removed]
      • Eric
        Exactly. In order to use a hand tap in it s virgin state you would have to have synchronization between the xyz motion as well as the spindle motor.
        Message 3 of 10 , Nov 1, 2011
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          Exactly. In order to use a hand tap in it's virgin state you would have to have synchronization between the xyz motion as well as the spindle motor. Otherwise, it would act like a regular end mill and cut out the material that would be your thread. Given there is no relief on the back end of a thread tap it probably wouldn't cut so well either.

          I rather like that video posted. Thank you. I will have to keep that in mind if I ever need a smaller internal thread cut.


          --- In SherlineCNC@yahoogroups.com, "sherlinenoob" <ly_smell@...> wrote:
          >
          > Why cant you use it natively but have to get rid of all of them except one cutting edge? If your helical motion is correct with the right feed/rpm can you just use a native manual tap to machine thread with all its teeth? I dont know, I guess you cant guarentee rpm or if there is slight error the other teeth may pass through material and cut off extra material?
          >
          > --- In SherlineCNC@yahoogroups.com, "RCGuy" <calvino.rc@> wrote:
          > >
          > > $10 tap vs $100 thread mill... tap any day of the week here! Ok well you can't use a tap as it is out of the box. You have to grind all the teeth off except for one row, and relieve the back, like this guy did. ..
          > >
          > > http://www.youtube.com/watch?v=-J_Xrkrs1Xc
          > >
          > > In all reality it isn't that hard to thread mill, its just making sure the machine is traveling in a helical interpolation at the right numbers and your good! I have personally seen on a Fadal VMC thread milling done with a VERY tiny {about size of a pencil eraser on a pencil?} thread mill creating precise taps in a piece of steel as a thread gauge.
          > >
          > > --- In SherlineCNC@yahoogroups.com, "sherlinenoob" <ly_smell@> wrote:
          > > >
          > > > Do you need special cutters per se? Have you tried the el-cheapo standard manual taps (not really el-cheapo since they arnt really cheap) as a thread cutter to do helical milling?
          > > >
          > > > I havent tried any of this of course but there is some cutting action capability right as a cutter. Maybe can do many passes?
          > > >
          > > > --- In SherlineCNC@yahoogroups.com, "Eric" <buckeyevs@> wrote:
          > > > >
          > > > > Helical milling with a thread form cutter is an option for a small enough cutter and large enough hole for those of us with plain old DC spindle motors. The trouble with this is that those cutters are usually pretty expensive. I made the purchase and it beats the heck out of single point threading on the lathe.
          > > > >
          > > > > Eric
          > > > >
          > > > > --- In SherlineCNC@yahoogroups.com, "sherlinenoob" <ly_smell@> wrote:
          > > > > >
          > > > > > Call me a noob but how do you tap holes in general with a CNC and also techniques with a sherline?
          > > > > >
          > > > > > I know you can manually press one in or have the fancier machines. In terms of CNC I know they also have similar tapping heads you can fit in. Is there other ways? Other fancier CNC machines with stepper or servo controlled spindles can plunge in and then unwind on the way out. But how is it done then on one directional DC spindles?
          > > > > >
          > > > > > Like getting the right tool with the right pitch cutting edges that is smaller than a bored hole and then helical entry into the hole sort of thing?
          > > > > >
          > > > > > Any techniques for the sherline?
          > > > > >
          > > > >
          > > >
          > >
          >
        • Sonny Mounicou
          I ve been successful using a thread mill to create acme nuts on my mill. It uses a threadmill with the rotary table mounted flat on work table. I have only
          Message 4 of 10 , Nov 28, 2011
          • 0 Attachment
            I've been successful using a thread mill to create acme nuts on my mill.
            It uses a threadmill with the rotary table mounted flat on work table. I
            have only used the material derlin, but the work very well. One of these
            days I will experiment with aluminum. You can see a copy of the ones I
            made here ... http://os1r1s.com/?p=486

            --Sonny



            On Tue, Nov 1, 2011 at 9:24 AM, Andy Wander <awander@...> wrote:

            > **
            >
            >
            > I have heard of folks using an old tap to mill threads by removing(with a
            > grinder) all but one tooth from the tap.
            >
            >
            > On Tue, Nov 1, 2011 at 8:32 AM, Scott Meyer <baldysm@...> wrote:
            >
            > > A thread mill and a tap are designed entirely differently.
            > >
            > > The teeth on a tap are on a helix. No tooth on the tap lines up with
            > > another tooth. So if you used a tap as a end mill, and milled around a
            > > shaft in a circle (no Z movement), you would have a smaller diameter
            > shaft.
            > >
            > > The teeth on a thread mill do line up. If you milled around a shaft on a
            > > circle, no Z movement, you would have a shaft with several V cuts into
            > it.
            > >
            > > The only way you could use a tap as a thread mill is if you moved the
            > > tap in Z 1 pitch per revolution. So, if you were doing 1"- 8 threads,
            > > you would move in Z .125 for every revolution of the spindle. You would
            > > also have to move 360 degrees around the shaft, per revolution. Pretty
            > > hard on the tap and you would get pretty crappy threads.
            > >
            > > With a thread mill, RPM and feed rate are irrelevant to the formation of
            > > the thread. As long as the machine is moving in a true helix, you'll get
            > > a good thread, regardless of feed or RPM.
            > >
            > > Scott Meyer
            > >
            > >
            > > On 11/1/2011 2:54 AM, sherlinenoob wrote:
            > > > Why cant you use it natively but have to get rid of all of them except
            > > one cutting edge? If your helical motion is correct with the right
            > feed/rpm
            > > can you just use a native manual tap to machine thread with all its
            > teeth?
            > > I dont know, I guess you cant guarentee rpm or if there is slight error
            > the
            > > other teeth may pass through material and cut off extra material?
            > > >
            > > > --- In SherlineCNC@yahoogroups.com, "RCGuy"<calvino.rc@...> wrote:
            > > >> $10 tap vs $100 thread mill... tap any day of the week here! Ok well
            > > you can't use a tap as it is out of the box. You have to grind all the
            > > teeth off except for one row, and relieve the back, like this guy did. ..
            > > >>
            > > >> http://www.youtube.com/watch?v=-J_Xrkrs1Xc
            > > >>
            > > >> In all reality it isn't that hard to thread mill, its just making sure
            > > the machine is traveling in a helical interpolation at the right numbers
            > > and your good! I have personally seen on a Fadal VMC thread milling done
            > > with a VERY tiny {about size of a pencil eraser on a pencil?} thread mill
            > > creating precise taps in a piece of steel as a thread gauge.
            > > >>
            > > >> --- In SherlineCNC@yahoogroups.com, "sherlinenoob"<ly_smell@> wrote:
            > > >>> Do you need special cutters per se? Have you tried the el-cheapo
            > > standard manual taps (not really el-cheapo since they arnt really cheap)
            > as
            > > a thread cutter to do helical milling?
            > > >>>
            > > >>> I havent tried any of this of course but there is some cutting action
            > > capability right as a cutter. Maybe can do many passes?
            > > >>>
            > > >>> --- In SherlineCNC@yahoogroups.com, "Eric"<buckeyevs@> wrote:
            > > >>>> Helical milling with a thread form cutter is an option for a small
            > > enough cutter and large enough hole for those of us with plain old DC
            > > spindle motors. The trouble with this is that those cutters are usually
            > > pretty expensive. I made the purchase and it beats the heck out of single
            > > point threading on the lathe.
            > > >>>>
            > > >>>> Eric
            > > >>>>
            > > >>>> --- In SherlineCNC@yahoogroups.com, "sherlinenoob"<ly_smell@>
            > wrote:
            > > >>>>> Call me a noob but how do you tap holes in general with a CNC and
            > > also techniques with a sherline?
            > > >>>>>
            > > >>>>> I know you can manually press one in or have the fancier machines.
            > > In terms of CNC I know they also have similar tapping heads you can fit
            > in.
            > > Is there other ways? Other fancier CNC machines with stepper or servo
            > > controlled spindles can plunge in and then unwind on the way out. But how
            > > is it done then on one directional DC spindles?
            > > >>>>>
            > > >>>>> Like getting the right tool with the right pitch cutting edges that
            > > is smaller than a bored hole and then helical entry into the hole sort of
            > > thing?
            > > >>>>>
            > > >>>>> Any techniques for the sherline?
            > > >>>>>
            > > >
            > > >
            > > >
            > > > ------------------------------------
            > > >
            > > > Yahoo! Groups Links
            > > >
            > > >
            > > >
            > >
            > >
            > > ------------------------------------
            > >
            > > Yahoo! Groups Links
            > >
            > >
            > >
            > >
            >
            > [Non-text portions of this message have been removed]
            >
            >
            >


            [Non-text portions of this message have been removed]
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