Last I looked, which has been a little while, you could get used Swiss-made ER collets on eBay for about $16-$20. If that price is close, you could pick one up in the specific size you need as needed, and not kill the budget. Much, anyway. ;)
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by:
Good judgement comes from experience. Experience comes from bad judgement.?
SEMPER GUMBY!
Improvise, Adapt, and Overcome. Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better.
Expect in one hand, expectorate in the other. See which one gets full first.
On Sunday, June 9, 2024 at 10:57:43 PM CDT, Dave Seiter <d.seiter@...> wrote:
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.
Bill in OKC too