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acme tap

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  • acme tap

    Does any one have a 7/16-10 left hand acme tap I need to make a new cross feed nut for my 9" SB. A Person on another site has one but if you don't have a bazillion posts you can't borrow it.

  • #2
    Have you thought about single point cutting it in the lathe? I cut a 3/8-12 on my lathe although there isn't much room for a mistake. I did have to grind a tool to do it. But it is very doable if you take your time.
    Jonathan P.


    • #3
      Japcas thats a good idea but the screw I have to fit the nut too, is also the cross feed screw on the lathe that I will be using to cut the thread.


      • #4
        Not hard to make a tap from a piece of acme screw, assuming the nut will be brass. Seems like a "how to" was posted here a few years back. The tap is normally done in two stages because the threads are too deep to cut in a single stage.


        • #5
          If you could bump up the size to 1/2-10 rh, I have that. But I just noticed the lh requirement. My only lh is 5/8-8
          Last edited by gvasale; 02-22-2010, 10:21 PM.


          • #6
            If you have a compound rest, you could remove the screw, lock the cross-slide, and use the compound feed to bore the nut. It would be a little more fidgety but a lot of the fun in this hobby is figuring out how to do something when you don't have the proper tool or machine.

            Another possibility if the end of the screw can be made accessible would be to mount the nut so that it could be removed and accurately replaced, then try it on the end of the screw. You would have to be sure you could set the cross-slide back to the same place each time.

            My first lathe job was boring a 56MM hole through a 4"x4"x4" aluminum block on a 6" AA Products lathe with a faceplate and an un-modified 3/8" drill bit held in the lantern tool post for a boring bar. That definitely wasn't the right machine or the right tool but it turned out fine.

            Good luck.
            Don Young


            • #7
              I just turned an acme screw today to replace the old one in my bp. I am planning on making a tap out of the left over acme screw and make the brass nut as well.



              • #8
                You can make a nut on a lathe to replace the one you have on the machine. The force is (should) only be in one direction, so it is just working against the back lash as you normally do. If it really worries you, lock the axis while you cut and/or use the compound for feed. I cut my first ACME nut for my lathe in that way.



                • #9
                  Yea, large diamiter nuts can be done with a boring bar with a threading bit inserted, little tricky but doable... making a tap is argueabley funner then internal acme threading however
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