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What are your Fears ? What process or procedure is holding you back?

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  • #16
    Originally posted by Doozer View Post

    With using the cutting tool where it put a compression load into the bed of the lathe,
    any slight digging of the cutter causes it to try and fold under itself, causing a break.
    If you put the cutting tool in tension where it pulls force from the bed of the lathe,
    any digging in of the cutter causes it to swing away and unload the cut, causing a
    reduction in cut load. Look at your force vectors.

    -Doozer
    Thanks --- I'll try putting it just a bit below center instead of dead on. Everything else is where it should be, short stickout, gibs tight, etc. Square to the spindle etc.

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    • #17
      Get it under it want to climb over.. I just use a the ruler trick, and put it on center..
      but I should add. The smaller and lighter a machine is, the tougher parting will be..

      the up side down rear parting tools seem to work well on small lathes..so does widening your cut..
      Last edited by 754; 09-08-2020, 12:04 PM.

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      • #18
        Originally posted by 754 View Post
        ...the up side down rear parting tools seem to work well on small lathes....
        Is that not what I said??.

        -D
        DZER

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        • #19
          Originally posted by 754 View Post
          Get it under it want to climb over.. I just use a the ruler trick, and put it on center..
          but I should add. The smaller and lighter a machine is, the tougher parting will be..

          the up side down rear parting tools seem to work well on small lathes..so does widening your cut..
          Well,. the holder itself angles the blade up at 8 deg. and there's another angle or two ground into the end of it.

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          • #20
            Originally posted by Doozer View Post

            Is that not what I said??.

            -D
            Perhaps in a somewhat indirect way -- lemme go check

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            • #21
              Originally posted by Doozer View Post

              Is that not what I said??.

              -D
              I did not see it..
              to be honest, I don't recall any 45 degree parting tools, are you referring to rake ground into the tool ?
              and if 8 degrees is part of the holder that seems a bit strange.
              Last edited by 754; 09-08-2020, 12:58 PM.

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              • #22
                Cutting any threads I've tried a few times and never seem to get the depth correct. It's to tight, then I go to far and it's as loose as can be. I think it comes down to the MATH, I failed in math all through school and that is probably my real fear.
                I am a HSM, only for my needs and a few friends, but still would like to be able to do it for different projects successfully.

                TX
                Mr fixit for the family
                Chris

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                • #23
                  Originally posted by MattiJ View Post
                  Getting old and/or moving shop
                  I agree. I'm 79 and my family is on my case to clean it out or in other words, sell. I tell'em I promise that I will have it cleaned out by the time I'm 100.
                  Sarge41

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                  • #24
                    Originally posted by Mr Fixit View Post
                    Cutting any threads I've tried a few times and never seem to get the depth correct. It's to tight, then I go to far and it's as loose as can be. I think it comes down to the MATH, I failed in math all through school and that is probably my real fear.
                    I am a HSM, only for my needs and a few friends, but still would like to be able to do it for different projects successfully.

                    TX
                    Mr fixit for the family
                    Chris
                    Wow, OK. I actually enjoy threading, mind if I share a few tips?
                    The math is technically correct but believe it or not, I cheat.
                    Nothing that I am likely to do requires 100% inspection.
                    Like you, it's just for myself, friends and family.

                    I coat the entire part with either sharpie marker or Dykem layout dye
                    I get my scratch pass, check it, and start cutting threads
                    When the dye *just* disappears, that's it. You're basically at your depth
                    As long as you had the OD correct originally.

                    When all the dye has disappeared, take "spring" cuts until nothing more comes off.
                    Then take a very fine mill file, laying flat across the tops of the threads and give them a light going-over at high speed. This knocks off the burr that rises up there and the burr will screw up your measurements every time.

                    Notice that no math was needed for any of that? That's because of the shape of the thread. Start with the correct OD and when the ink disappears you are at basic size plus a few spring passes.

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                    • #25
                      Originally posted by Mr Fixit View Post
                      Cutting any threads I've tried a few times and never seem to get the depth correct. It's to tight, then I go to far and it's as loose as can be. I think it comes down to the MATH, I failed in math all through school and that is probably my real fear.
                      I am a HSM, only for my needs and a few friends, but still would like to be able to do it for different projects successfully.

                      TX
                      Mr fixit for the family
                      Chris
                      Honestly this is partly the reason for this topic.. tell us the problem..and get advise.,
                      threading , I don't use much math, I glance at the engraved depth on tbd fistail...maybe.
                      in a nutshell.. sharp Vee looks like sharp veee., usually you can see it....sneak up on the finish.. never expect to end with a 5thou cut..on your first off.
                      another big thing, tool keen ness.. if it's not sharp it may not cut on a few light passes, then get in on the next and take more than you moved the tool...I suspect that MAY be the problem.

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                      • #26
                        Originally posted by 754 View Post
                        another big thing, tool keen ness.. if it's not sharp it may not cut on a few light passes, then get in on the next and take more than you moved the tool...I suspect that MAY be the problem.
                        X2 on the sharp tools. I use HSS with a decent amount of rake for most threading, and I keep it dead sharp. Only need to hit the top with a stone to give it a touch up. I quit using carbide for threading because of the crap finish.

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                        • #27
                          Originally posted by Doozer View Post
                          Van man-

                          Throw those 45° angle parting tool holders for the lantern post away.

                          -D
                          Those offset holders have saved my butt a few times when I couldn't get the straight one close to the chuck. The key is to not use the rocker and replace it with a solid washer of the appropriate height. This eliminates the rotational error that the rocker causes.
                          Location: Northern WI

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                          • #28
                            Originally posted by Mr Fixit View Post
                            Cutting any threads I've tried a few times and never seem to get the depth correct. It's to tight, then I go to far and it's as loose as can be.
                            Take a spring pass. Leave the dials where they are and take another cut. It's surprising how much comes off sometimes.

                            Edit: Just noticed that nickel-city-fab said the same thing. He doesn't have exclusive rights to spring passes

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                            • #29
                              Originally posted by Galaxie View Post

                              Those offset holders have saved my butt a few times when I couldn't get the straight one close to the chuck. The key is to not use the rocker and replace it with a solid washer of the appropriate height. This eliminates the rotational error that the rocker causes.
                              Ahhhhhhh yes 45 degrees side ways I have one,, I was thinking rake or tool slant in vertical plane...offset holder I call it.

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                              • #30
                                Originally posted by 754 View Post

                                Ahhhhhhh yes 45 degrees side ways I have one,, I was thinking rake or tool slant in vertical plane...offset holder I call it.
                                The cause of many broken lathe compounds.

                                -D
                                DZER

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