Announcement

Collapse
No announcement yet.

turning small M1.4x0.2 threads (127TPI)

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • turning small M1.4x0.2 threads (127TPI)

    After I got the DRO installed I had to try turning some tiny threads. Here is a M1.4x0.2 thread:



    Had to dig out macro extensions for DSLR as I can't say much anything about the thread by bare eye even if I'm near-sighted "young" guy.
    Looks reasonably good but it l think thread root is bit excessively rounded. Maybe that's where I need the HSS tool?

    Started at 0.02mm dept of cut and switched to 0.01mm dept of cut for the last 5 passes or so.
    Used chinabay DCGT insert re-sharpened to 60 degree on a 3000 grit lapidary diamond disk, no further polishing.

  • #2
    Why not do something larger like an M12x0.2 instead? That would look cool.

    Comment


    • #3
      Was running pretty much blind of by DRO numbers without much clue what is happening... Anyone got USB microscope or something like that mounted on a lathe?


      Was stinking of USB microscope and cheapo android tablet combo. Would be also nice when boring small diameter holes...

      Comment


      • #4
        Originally posted by MattiJ View Post
        Anyone got USB microscope or something like that mounted on a lathe?
        Dan Gelbart has one on his.
        https://www.youtube.com/watch?v=otSjut1iGGk&t=8m30s

        Comment


        • #5
          Originally posted by MattiJ View Post
          Was running pretty much blind of by DRO numbers without much clue what is happening... Anyone got USB microscope or something like that mounted on a lathe?


          Was stinking of USB microscope and cheapo android tablet combo. Would be also nice when boring small diameter holes...
          I have one I use in the mill spindle. With the DRO it makes the mill into a big optical comparator for measuring features on parts that can't be measured with a mike or caliper. I scribed an X and Y axis centerline on a sheet of Mylar and taped that to the tablet screen. It works like a champ. The same setup would also work fine on the lathe.
          Kansas City area

          Comment


          • #6
            I recently purchased a Bluetooth microscope to use with the cell phone. I intended to use it for checking the grind on small drills. Now I think I should make mounts dor the mill and the lathe. Thanks for the suggestion.

            If you are using a microscope with a PC look on line for software called Centre Cam. It allows you to put crosshairs or a circle on the image and to adjust the size and position of the hairs and circles.

            Comment


            • #7
              I don't know how one could cut such small features with a carbide tool! A HSS tool, carefully ground and lapped, would do a much better job IMO. But I have trouble imagining making such small things... and I used to service/repair watches!!

              Please post further progress!!

              Pete
              1973 SB 10K .
              BenchMaster mill.

              Comment


              • #8
                Originally posted by 3 Phase Lightbulb View Post
                Why not do something larger like an M12x0.2 instead? That would look cool.
                I've seen 120tpi on a diameter of about 1 1/8. (Leveling blocks for the synchrotron. Local machine shop built a bunch of them.)
                Location: Saskatoon, Saskatchewan, Canada

                Comment


                • #9
                  Originally posted by 10KPete View Post
                  Originally posted by MattiJ View Post
                  ... I had to try turning some tiny threads. Here is a M1.4x0.2 thread:

                  ... I have trouble imagining making such small things... and I used to service/repair watches!!
                  Yes.

                  MattiJ might post another photo showing his part beside something familiar to give context for size. I have a sense of how small those are thanks to a hobby where M2.0 fasteners are common.

                  Threading M1.4 with carbide isn't high on my todo list. What is the material?

                  Comment


                  • #10
                    Originally posted by EddyCurr View Post
                    Yes.

                    MattiJ might post another photo showing his part beside something familiar to give context for size. I have a sense of how small those are thanks to a hobby where M2.0 fasteners are common.

                    Threading M1.4 with carbide isn't high on my todo list. What is the material?


                    Material is S355 rod, probably equivalent to 1018 cold drawn.

                    Comment


                    • #11
                      There you go.

                      I've been wondering whether any run-of-the-mill video cameras are going to have the kind of macro capability needed to display the M1.4 thread in a useful manner. I have a 120mm-equiv Macro lense (Micro4/3) that I think would give satisfactory enlargement at sufficient distance. Maybe one of the various inspection cameras has the necessary visual and harsh environment capabilities for a reasonable expenditure?

                      Originally posted by MattiJ View Post
                      Material is S355 rod, probably equivalent to 1018 cold drawn.
                      CD1018 - so it isn't as if only carbide will do the job. Like 10KPete, I think HSS could give pleasing results. The part is so small, you aren't giving up any real world speed.
                      Last edited by EddyCurr; 01-26-2019, 02:46 AM.

                      Comment


                      • #12
                        Originally posted by 10KPete View Post
                        I don't know how one could cut such small features with a carbide tool! A HSS tool, carefully ground and lapped, would do a much better job IMO. But I have trouble imagining making such small things... and I used to service/repair watches!!

                        Please post further progress!!

                        Pete
                        Biggest problem with the tool is to judge if its sharp or not. It looks sharp, it feels sharp, it even smells like sharp but without that shop(USB) microscope its reaaally hard to say for sure.
                        Same problem with HSS and carbide. I never seem to get HSS any sharper than GOOD carbide no matter how much time I spend on grinding and lapping the HSS tool.

                        My stinking is that you would probably need better grade of HSS or plain old carbon steel. BOG standard HSS grain size is worse than these modern tungsten carbide inserts have.
                        If anyone has attempted to sharpen woodworking tools out of "old school" HSS they probably know that its really difficult to sharpen for razor sharpness. (not just figure of speech but something that you can actually use to shave your arms or face)

                        Comment


                        • #13
                          Originally posted by MattiJ View Post
                          Originally posted by MattiJ View Post
                          Used DCGT insert re-sharpened to 60 degree on a 3000 grit lapidary diamond disk, no further polishing.
                          Same problem with HSS and carbide. I never seem to get HSS any sharper than GOOD carbide no matter how much time I spend on grinding and lapping the HSS tool.

                          My thinking is that you would probably need better grade of HSS or plain old carbon steel. BOG standard HSS grain size is worse than these modern tungsten carbide inserts have.

                          If anyone has attempted to sharpen woodworking tools out of "old school" HSS they probably know that its really difficult to sharpen for razor sharpness. (not just figure of speech but something that you can actually use to shave your arms or face)
                          For HSS, what about going beyond grinding & lapping?

                          Knife people finish edges by stropping: perhaps initially on leather loaded w/ 0.?? ┬Ám diamond spray, then completing w/ plain leather. I don't know whether this is feasible for a tool as small as you are working with, but offer the thought for consideration.

                          Comment


                          • #14
                            Was this an exercise, or do you have a use for such a small screw? It got me thinking what the Smart & Brown model A that I use is capable of. It does 8 to 76 tpi natively, and I can halve the leadscrew gearing to achieve up to 152 tpi. It can do metric threads, but I have only calculated down to the 0.7mm pitch. Using the feedscrew, it will un at 0.001" per turn natively, so it is capable of 0.0005" per turn, 2000 tpi. I don't think those pitches would be more than just a pipe dream, though.

                            Comment


                            • #15
                              Originally posted by old mart View Post
                              Was this an exercise, or do you have a use for such a small screw? It got me thinking what the Smart & Brown model A that I use is capable of. It does 8 to 76 tpi natively, and I can halve the leadscrew gearing to achieve up to 152 tpi. It can do metric threads, but I have only calculated down to the 0.7mm pitch. Using the feedscrew, it will un at 0.001" per turn natively, so it is capable of 0.0005" per turn, 2000 tpi. I don't think those pitches would be more than just a pipe dream, though.
                              Just an exercise at the moment.
                              My Kerry would do 288 TPI inch thread and 0.04mm metric pitch but I have one broken gear in the norton box and I have placed it in the last position so I'm limited to 144TPI imperial and 0.08mm metric.

                              Geartrain, leadscrew and half-nut all have too much slop and flex combined at this level. Too little oil on the ways or sneezing loudly probably results 1/2 pitch variation in the thread position

                              Comment

                              Working...
                              X