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  • Turning small stock...

    I'm currently working with some 1/8" O1 tool steel rod, making parts for a couple of project air guns. My question is, how do you guys hold stuff this small? The smallest my chuck will hold is about 1/4" diameter, I've had to resort to using my mini mill as a vertical lathe. Is my only option a collet chuck, or is there another way? And if a collet chuck is the only viable option, what's a decent one that won't break the bank? Or maybe a better question, which one's should I avoid like the plague? BTW, if it matters, the machine is an older 12x24 belt drive Grizzly with a threaded spindle, 2.25"x8. Thanks, gents.

    Dave

  • #2
    I use 5C collets held in a square collet block held in my 4 jaw chuck. Its a little annoying, but it gets the job done nicely.
    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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    • #3
      how about a split bushing? 1/8 ID X 5/16 OD. If you are only doing one or two pieces , a shotr length of soft copper tubing will crush in the chuck jaws and hold the stock.

      Joe B

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      • #4
        Originally posted by JoeCB
        how about a split bushing? 1/8 ID X 5/16 OD. If you are only doing one or two pieces , a shotr length of soft copper tubing will crush in the chuck jaws and hold the stock.

        Joe B
        They must use really thick copper tube where you live!
        Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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        • #5
          Originally posted by Black_Moons
          I use 5C collets held in a square collet block held in my 4 jaw chuck. Its a little annoying, but it gets the job done nicely.
          I do the same except I use a hex block in my 3 jaw
          Ernie (VE7ERN)

          May the wind be always at your back

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          • #6
            all good ideas.

            another is take a a short length of round stock, say 5/8 or so. Cross drill and tap for a set screw. Chuck in the three jaw, spot drill, drill and ream 1/8 - do a pass with a miny boring bar before reaming if you want guaranteed perfect alignment of the hole. This is an easy way to hold the 1/8 stock....and so long as you don't remove it will be quite concentric. Mark the location of a jaw on it and you should even be able to repeat fairly well
            in Toronto Ontario - where are you?

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            • #7
              hm, so what acuracy is yout tailstock set to?

              i would put a small independent 4 jaw chuck into the big chuck.

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              • #8
                Originally posted by dian
                hm, so what acuracy is yout tailstock set to?
                who's tailstock and why?
                in Toronto Ontario - where are you?

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                • #9
                  Originally posted by daved20319
                  I'm currently working with some 1/8" O1 tool steel rod, making parts for a couple of project air guns. My question is, how do you guys hold stuff this small? The smallest my chuck will hold is about 1/4" diameter, I've had to resort to using my mini mill as a vertical lathe.
                  Dave
                  Buy used ML7 of Myford (England).
                  Spares still available of manufacturer and plenty on e-bay too.
                  I have one and I am *extremely* pleased with it.
                  Tuned to 0.0005 in/ft accuracy... for a 43 yo girl.
                  She got general overhaul 8 years ago, when was bought.
                  Will serve next 80 years, I believe.
                  Modern crap stand no chance to compete whatsoever...

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                  • #10
                    "spot drill, drill and ream 1/8 - do a pass with a miny boring bar before reaming if you want guaranteed perfect alignment of the hole."

                    well it dont know (iv had a couple of chiloms already), but dont you do this from the taistock?

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                    • #11
                      "guaranteed perfect alignment of the hole."

                      so if the tailstock is not perfect, youll get a conical hole and the set screw will introduce an error of 0.01 mm (at least).

                      but then again, iv had two chilloms already, so forgive me for thinking aloud.

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                      • #12
                        Originally posted by dian
                        "spot drill, drill and ream 1/8 - do a pass with a miny boring bar before reaming if you want guaranteed perfect alignment of the hole."

                        well it dont know (iv had a couple of chiloms already), but dont you do this from the taistock?
                        no problem thinking out loud...in my experience with the work rotating a spot drill will get pulled into cutting a very concentric cone...even if the tailstock is off (a bit). use a very soft touch when starting and let the bit get pulled to the centre of the work. If the tails stock so so far out this wont work, slew the compound over and single point the cone

                        Once the hole is spotted, the tailstock being out will have minimal to an unmeasurable affect on the drill and reamer's path, again assuming its not out an extreme amount

                        The part that guarantees a true bore is to follow up drilling with a single point boring tool before reaming. I know its small hole but not so small you can't use or get a boring tool that'll work. The challenge then is that this 1/8 hole might be too long to easy to bore its length....so what you do is single point bore, very carefully, a short length at exactly 1/8. The sides of the reamer will then follow this and cut a very true hole, regardless of the tailstock being out.....its pulled true by the single point bore. Reamers are the length the are to allow a bit flex.....ever turned the drill press on and seen a reamer with a a bit of wobble to it?...but it goes away and doesn't affect the bore once you start reaming? same thing here.

                        All implies a matter of reasonableness.....if its 1/2" of course its not going to work, but a tailstock being out bit does material effect the accuracy of holes drilled and reamed from it using the above techniques

                        The OP may not even need concentricity with the chucked part, then its mostly moot....but if he does this will work very well.
                        in Toronto Ontario - where are you?

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                        • #13
                          What chuck system wont break the bank?
                          I think the Grizzly has an MT-4 taper. If so, an adapter MT-4 to MT-3 and an MT-3 collet should work. CDCO Tools have an inexpensive set, and individual units are about $12.00 each.
                          Duffy, Gatineau, Quebec

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                          • #14
                            Split Bushings............reusable, simple, cheap
                            BudB

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                            • #15
                              And now to throw another wrench....

                              You mentioned you wanted to turn this material down but you didn't mention the degree of accuracy you needed in your final diameter.

                              This little bit of wisdom was given to me by Bill Huxhold (I bow to the east for my machining god ) If you need an accurate small diameter you may need to start with a larger diameter rod to prevent deflection and turn the diameter you need in a single pass with a slower feed. The reason is that the larger diameter provides it's own support while you are making the cut.

                              Thanks Bill.

                              If you'd seen my high school pin punch you'd know why I'm saying that. But I got the tempering just right.
                              Allans Rule: Anything worth doing is going to be a pain in the butt.

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