I'm also looking into purchasing a collet chuck system and have a few questions. The 18 piece English unit ER-32 collet sets sold by 800watt are missing the 13/32, 17/32, and 21/32 sizes, but otherwise have continuous coverage by 1/32" (0.79375 mm) steps. Do these collets have enough range to cover these missing sizes. If not, I'll probably go with the 18 piece metric unit set, which has continuous coverage by 1 mm steps.
I'll probably get the Beall chuck for my 1 1/4 x 8 head thread. PSI won't fit. Thanks for your help.
Dave
If I understand your question, the answer would be ... no the fractional inch collets would not have decent coverage if the 13/32, 17/32, and 21/32 sizes are omitted.
Let's say you were making your own pen and the final lower diameter wound up at .510 diameter (a popular size) and you wanted to chuck it up to work on it.
The 1/2" collet would be too small for it to even fit and the next size in the "standard set" would be 9/6 with a clamping range of .523 - .562 which of course would be too large for the pen blank so you would either need to buy the 17/32 collet individually (like I did) OR wrap tape around the blank so the 9/16 collet would work.
Since you are starting fresh, going the metric set would be the way to go
IF..... the price of the sets are comparable
AND you keep a conversion chart handy so yuo'll know which collet to reach for when you have a fractional size in mind
OR just teach yourself to deal strictly in metrics when making your pens (A feat easier said than done, at least for me)