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Single pointing 0-80 internal thread

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  • #16
    I have been running a lathe since 1950. This is as good as I have ever seen. Edwin Dirnbeck

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    • #17
      damn, that's impressive! Just getting the threading tool profile correct at that size is no trivial endeavour.

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      • #18
        Thank you all for your kind words. My wife and kids don't get it. The guys at work won't either. This is one of a few groups that understands what went into this.

        I'm over 50 and use a lupe when I need to see up close. The trick with doing tiny stuff is to get a measurement and then go off of the dials much like a pilot uses instruments to fly at night. Unfortunately, this exercise didn't allow for that; hence the Dykem.

        The lathe used is an Atlas 618. I have a Rivett 608, this exercise had too much risk of a crash to use it.

        -Bob

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        • #19
          Originally posted by J Tiers View Post
          Good for you! The slack in the half nut system of my old Logan would be enough to mess up threading that fine, so I would use a tap for it.
          Tap or not, you guys are all better than me. I'd send that job down the road! Good on ya.

          Southwest Utah

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          • #20
            Originally posted by mattthemuppet View Post
            damn, that's impressive! Just getting the threading tool profile correct at that size is no trivial endeavour.
            And THAT is the truth........
            1601

            Keep eye on ball.
            Hashim Khan

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            • #21
              That's an impressive feat. Nicely done.

              While I tend to lean on the side of practical when I make stuff, I still like to take the long way sometimes just to prove to myself that it can be done, and also to learn something. You have to step outside your comfort zone once in a while.

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              • #22
                I applaud your deed.
                I really do.
                But personally, my time is worth more
                than farting around with something like this.
                Maybe if you are waiting for a part that is holding up a production line or something,
                but other than that, nice to keep in practice I guess.

                -D
                DZER

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                • #23
                  The lathe I use only goes to 76tpi so I'll give it a miss, also, the finest laydown inserts I have are 0.5mm, a little coarse.

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                  • #24
                    Originally posted by Doozer View Post
                    I applaud your deed.
                    I really do.
                    But personally, my time is worth more
                    than farting around with something like this.
                    Maybe if you are waiting for a part that is holding up a production line or something,
                    but other than that, nice to keep in practice I guess.

                    -D
                    but I'm sure that you didn't get to the level you operate by doing the same thing over and over, right? Skills come from challenges and mistakes, which usually come from doing something you don't know how to do A life without intellectual challenges is my idea of hell.

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                    • #25
                      Originally posted by old mart View Post
                      The lathe I use only goes to 76tpi so I'll give it a miss, also, the finest laydown inserts I have are 0.5mm, a little coarse.
                      Ja, I was going to say.... I don't think I have enough magnification to grind a suitable tool!

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                      • #26
                        I was trying to place the lathe and you said it was an Atlas 618 (woot!), but it has a sealed cartridge spindle bearing - how did that come about? Any details?

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                        • #27
                          Bob

                          Now that is really a challenge and skill building exercise.

                          The smallest internal I have done is 2 - 112 TPI for a mixer needle. Another modeler suggested at that size to make your tool upside down and take the cut off the back side(that way you are still going CCW if you have threaded spindle) and so you can see it (ha ha) still needed a magnifier but at least I did not have to twist my neck all around. Or use a left hand tool and run the lathe in reverse, either way a little better view.

                          I am curious how you kept all the play out of everything ie lead screw, and half nut. Did you do anything specific? For example not disengaging the half nut just running under power backwards, not cutting the thread under power but turning the spindle by hand?

                          Again fantastic challenge.

                          Bob

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                          • #28
                            When I saw the title I was all set to advise you to use a tap. 0-80? I have the tap and have tapped 0-80 holes. But single pointing it? I would have sworn it was all but impossible. Just making that tool is a real challenge. But you DID IT!

                            I am impressed.

                            Nothing is impossible if you set your mind to it. We all need to remember this. Thank you for showing it anew.

                            PS: My wife and family would also be totally clueless.
                            Last edited by Paul Alciatore; 02-24-2020, 04:35 PM.
                            Paul A.
                            SE Texas

                            Make it fit.
                            You can't win and there IS a penalty for trying!

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                            • #29
                              Thank you for the compliments.

                              Doozer- I guess we are just wired differently.

                              Matt- The lathe is a 618 Square head. They changed over to this style in the early 1970's.

                              Bob-
                              I actually considered running the lathe in reverse with the tool mounted upside down. I would have had to rewire the motor to do it. I just didn't feel like going to that extent for this. I "tuned" the lathe years ago and took all the slop out. This included the half nuts and the lead screw bearings. I also combined the best parts from three 618s to build this one.

                              I used an indicator to to disengage the half nuts. At 80 threads per inch the carriage is not flying along. I could pretty much hit zero on the indicator, a few times I missed by .005. This was fine because I had a .020 safety margin. I just used the same number on the threading dial to engage the half nuts.

                              -Bob

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                              • #30
                                Regarding small stuff, I remember a story that my dad told probably back in the 60's. He worked in a department of GM that made diesel injector spray tips and the holes were drilled by hand with sensitive drill presses. I think the holes were a little bit under .010". They sent a drill bit to Japan for a trade show and it came back with a hole through it.

                                Later they started to burn the holes with a piece of wire on special built edm's. I worked in that department for a while and the holes were usually burned in with .004" wire.
                                OPEN EYES, OPEN EARS, OPEN MIND

                                THINK HARDER

                                BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

                                MY NAME IS BRIAN AND I AM A TOOLOHOLIC

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