Wanted 5C Collets

[FLtenwheeler]

Thanks for all the input.

Tim

[FLtenwheeler]

Just buy the following collects - 11/64 - 9/64 - 3mm - pretty simple these are within a few thou of what you require and will pull down to the size you want quite easy .
A 5C collet can pull down quite a way from the stated measurement .

According to Hass a 5C collet is good to 1/64" smaller than the standard size.

Tim

[Harold_V]

According to Hass a 5C collet is good to 1/64" smaller than the standard size.

While you can use single taper collets that way, it's not a good idea. As the collet goes below nominal, it grips only at the outer edge. Not only does that offer the opportunity for the collet to grip a part in a less than parallel manner, it also offers the risk of damaging the item being gripped. If it is subjected to a heavy cut, it oscillates around the gripping point, leaving a tapered groove and a slightly raised ridge, with the added risk of the part spinning in the collet under load. All in all, not a great way to use the collet. It also can collapse the collet, so inserting nominal sized material can become troublesome. That's not likely to happen with a properly heat treated collet, however.

H

[Bill Shields]

I take a piece of brass rod of a known OD

Drill a hole in it the needed size for the bolt

then slit it down through one side with a slitting saw.

clamp in collet

instant collet of any size needed.

[platypus20]

I bought out a machinery supply store, I have odd sizes, but none small enough. Too bad you do not need R8, I have 6 lyndex 1/16” collets.

[Greg_Lewis]

I take a piece of brass rod of a known OD

Drill a hole in it the needed size for the bolt

then slit it down through one side with a slitting saw.

clamp in collet

instant collet of any size needed.

Shields scores again. When are you going to write the book, Bill: The Genius of Bill Shields?

[Harold_V]

If the parts to be gripped are a constant size, and the bushing is fairly thin, you don't even have to split the bushing. I've made them for as much as a 1/32" mismatch (between collet and part size). So long as it will slip over the parts and the fit is good, it grips just fine, and isn't permanently shrunk when used, as you don't reach the yield point of the material when closing the collet. I make mention because it saves one operation (including deburring), although not a great deal of time. Good to know when time is of the essence.

H

[Bill Shields]

short book....

[FLtenwheeler]

A new 0.164" 5C collet from Hardinge is $60. But the shipping and handing is more than that. The 9/64" collet is working for me to trim the #8 bolt head to size.

Tim

[Harold_V]

Hmmm. That doesn't make sense. A 9/64 collet has a theoretical ID of .140625". That's .024" smaller than the theoretical OD (which is smaller than .164"). It's a reasonable fit for a #6 screw, though.

I'll assume you are using an 11/64 collet (for a #8 screw). If so, the mismatch of the collet versus the screw is all of .0078" (theoretical), but with the allowance, there's a mismatch of about .009".

The collet is capable, but it's not a great solution (although I've been known to do it, too!).

H