Modelman
Titanium
- Joined
- Sep 12, 2007
- Location
- Northern Illinois
One of the things missing from this discussion is the style of the collet. The collets that people are saying don't have much range, R-8, 5-C, etc. are only split from one end. If you think about it, as the collet collapses, it has to bend, and the sides of the internal hole become non-parallel. This isn't good for gripping the tool, and excessive bending will "spring" the collet and it won't work well thereafter.
There are other families of collets, DA, ER, TG, that are split alternately from both ends. This keeps the sides of the internal hole parallel as they close, and these have greater range. I have a set of ER-40 collets that go from 3mm to 26mm in 1mm increments. We are an inch measurement shop, but this set has the ability to grip any tool between 1/8" and 1" diameter, which is handy for tools with odd size shanks like drills and reamers.
Dennis
There are other families of collets, DA, ER, TG, that are split alternately from both ends. This keeps the sides of the internal hole parallel as they close, and these have greater range. I have a set of ER-40 collets that go from 3mm to 26mm in 1mm increments. We are an inch measurement shop, but this set has the ability to grip any tool between 1/8" and 1" diameter, which is handy for tools with odd size shanks like drills and reamers.
Dennis