Two years ago I got chinese ER40 chucks in a number of styles (R8, 40 taper, MT3, and one I'm forgetting at the moment), and the chucks are all within .0002-.0005 runout, but the collets I've tried all seem to have about .0015- .002 runout when installed, regardless of what I do to try and true them up.? I don't use them much, so I'm waiting for a local shop auction or sale of US made collets to see if they are any better.
-Dave
On Saturday, June 8, 2024 at 10:06:02 PM PDT, Keith S. Angus <keithsangus@...> wrote:
And of course the sort of runout you should expect is more like 0.0004"
If you can do the M12 thread and recess, then the 8¡ã taper shouldn't be too bad - might take a few goes to get it right. Then it's just the outer thread to take the nut. These can be odd sizes and pitches but so far I've found the right ones on Ebay. I haven't bought them, but I was considering setting up to make the holders on a bigger lathe, using screw cutting and finishing off with a die. As I've said before, if you make the holder of brass you'll give yourself the best chance of getting it right, and it shouldn't wear significantly with our sort of use. I find that collets work very nicely in brass holders, although I haven't made them for ERs.
