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  • #16
    For small stuff holding I usually use either collets or a drill chuck. I made a small adapter for the drill chuck so that it fits in to a collet and has a hole through it, so I can hold longer rods in it. The drill chuck has a very good repeatability and accuracy, I think it was spec'd at 0.015 mm runout.
    Amount of experience is in direct proportion to the value of broken equipment.

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    • #17
      I have an ER25 collet chuck on a morse taper with a drawbar that I can pull into my heatstock taper. Also fits my dividing head.
      Peter - novice home machinist, modern motorcycle enthusiast.

      Denford Viceroy 280 Synchro (11 x 24)
      Herbert 0V adapted to R8 by 'Sir John'.
      Monarch 10EE 1942

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      • #18
        jaakko, what drill chuck is that? the last one i checked had a runnout o 0.15 mm.

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        • #19
          Originally posted by Clevelander

          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.
          This technique works very well for tapers also. I had a need to make
          replacement "shear pins" for our lathes, brass about 1-1/2 long by
          about 3/16 (I forget the taper pin number) but was told by a friend
          who has been into small models for ages to start with a larger diameter
          and take it all at once, like you said. WORKS like a dream. :-)
          ...Lew...

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          • #20
            Originally posted by dian
            jaakko, what drill chuck is that? the last one i checked had a runnout o 0.15 mm.
            They are called "notcheaps", usually spec'ed with a nice DIN standard for runout and some of them use hydraulics to lock the drill bit.

            If your drill chuck has 0.15 mm runout, how are you going to drill anything reliably with it? I would toss that out to scrap bin immediately.
            Amount of experience is in direct proportion to the value of broken equipment.

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            • #21
              Dave,

              What chuck diameter are you using? My 12 x 36 Grizzly came with 6" 3-jaw chuck, capable of holding .090" with .001" runout. Maybe it is time for you to look for another chuck...

              In case I need to hold even smaller diameters I mounted a 2" 3-jaw chuck from Horrible Freight on a cylindrical arbor. The arbor goes in the big chuck. This 2" chuck is very inexpensive and is not so good except for special needs. I have ground the jaws, so the runout now is more or less acceptable. This chuck can hold less than .040" diameter. The arbor has a hole through of about 1/8" for a long stock.

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              • #22
                jaakko, a regular drill chuck will have a runout of 0.3 mm.

                so, first i bought a bison class 1, advertised at 0.07 mm. it had 0.15. too much trouble sending it back. next i got a rِhm spiro (was on sale, something like 150 $), advertised at 0.05 mm. it has 0.15 and im sending it back. there is an albrecht chuck advertised at 0.020-0.045, but im not buying it at 250 $, because i dont believe it.

                if you got a chuck with 0.015 mm runout im bidding 200 bucks for it.

                i measure like this.

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                • #23
                  dian, a lot of the detail there is in shadow - what's going on at the front of the chuck - next to three jaw, hows the outboard end of the large taper held and how are you testing - ie rotating the chuck between centres....or rotating the 3 jaw
                  in Toronto Ontario - where are you?

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                  • #24
                    dian, attach that drill chuck to your milling machine or drill, wherever that taper fits, then put a ground pin in it and measure the runout.

                    If you have a good drill chuck, you can use it to hold a chucking reamer and get perfect results.
                    Amount of experience is in direct proportion to the value of broken equipment.

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                    • #25
                      i have yet to find a ground pin (or anything else) that is perfectly round. try rotating the ground pin in the chuck and you will get a different amount of runout.

                      somehow i thought this was the standart way of doing in: the drill chuck is on a trued pin and the lathe chuck is rotated.

                      i still would be interested to know, what drill chuck gives you 0.015 mm runout.

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                      • #26
                        Originally posted by dian
                        i have yet to find a ground pin (or anything else) that is perfectly round. try rotating the ground pin in the chuck and you will get a different amount of runout.

                        somehow i thought this was the standart way of doing in: the drill chuck is on a trued pin and the lathe chuck is rotated.

                        i still would be interested to know, what drill chuck gives you 0.015 mm runout.
                        You can easily find ground pins (like dowel pins) that are more than round enough for these tests.

                        If you get different runout when changing the pin position, then your chuck is not in good condition or the pin is not straight/round or there is junk between the pin and the jaws.

                        What you mean by a trued pin?

                        I'll show you a photo once I get off from work later today of the drill chucks I'm talking about. And yes, they do cost 200-300 EUR per chuck, but worth every cent.
                        Amount of experience is in direct proportion to the value of broken equipment.

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                        • #27
                          Originally posted by Jaakko Fagerlund
                          dian, attach that drill chuck to your milling machine or drill, wherever that taper fits, then put a ground pin in it and measure the runout.

                          If you have a good drill chuck, you can use it to hold a chucking reamer and get perfect results.
                          I second putting it in a mill and measuring the runout.
                          Michael

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                          • #28
                            Here is the OP:

                            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. 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
                            In my lathe for that sort of work I use ER-32 collets which each have a gripping range of 1mm (~0.04") from 2mm (~.08") to 20mm (~0.80") with 18 collets in 1mm steps and each has a griping range of 1mm (~0.04").

                            1/8" = 0.125" x 25.4 = 3.175mm which will fit in the 3-4mm collet.





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                            • #29
                              Originally posted by dian
                              i have yet to find a ground pin (or anything else) that is perfectly round. try rotating the ground pin in the chuck and you will get a different amount of runout.

                              somehow i thought this was the standard way of doing in: the drill chuck is on a trued pin and the lathe chuck is rotated.

                              i still would be interested to know, what drill chuck gives you 0.015 mm runout.
                              So you've turned the spigot in situ then mounted the chuck on it? Not a bad a bad way to come at it as it somewhat isolates the chuck from arbor.

                              I've done as Jakko describes with the pin, if the results are good all is well....but if not there is a weakness with this in that in does not isolate the error to chuck or arbor. I remember once having a Jacobs chuck that I thought was terrible, replaced the crappo arbor and bingo it was perfect.

                              the testing process is about isolating where the error is. First indicate the inside of your mill or drill's spindle, whatever the taper mount goes into. Should be fine, but we want to be methodical to eliminate error.

                              Then remove the chuck from the arbor and mount the arbor in the mill (after carefully cleaning and inspecting the tapers). indicate the arbor.

                              If its good, mount the chuck on the arbor, again carefully inspecting and cleaning the tapers, re-attach to the arbor. You don't need a ground pin, (a pin is great if you have one but don't let that stop you) you just need something round. Turn a short piece and strive for the best finish you can get, it'll be as round as your lathe's bearings.

                              mount it in the chuck and indicate. being aware to look for dirt, burrs, warts and pimples on the tapers as the obvious cause, this series will tell you where the problem is
                              Last edited by Mcgyver; 03-06-2012, 09:22 AM.
                              in Toronto Ontario - where are you?

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                              • #30
                                Originally posted by oldtiffie

                                In my lathe for that sort of work I use ER-32 collets which each have a gripping range of 1mm (~0.04") from 2mm (~.08") to 20mm (~0.80") with 18 collets in 1mm steps and each has a griping range of 1mm (~0.04").

                                1/8" = 0.125" x 25.4 = 3.175mm which will fit in the 3-4mm collet.





                                Love it! how is that Collet chuck held in there?

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