Don (always the voice of reason) Nichols sez:

"The discussion was about 5C collets, which are the ones which
come from many makers in many degrees of quality.
Don't worry about it. The typical use of a collet block is not
going to require the accuracy that you want from a lathe spindle. The
most common use of the hex collet blocks is milling a hex head on a bolt
which you have made in an uncommon size. The same thing with a square
collet block -- making the screw heads found on older lathes for common
locking screws. The precision is not really that important. The block
and the collet is simply a convenient way of holding the workpiece,
especially if you don't have a dividing head with a 3-jaw chuck on it."


Many years ago I bought an expensive "complete" set of W. Germany 5-C collets, graduated by 32 nds.
Soon, I was overtaken by the consuming desire to fluff out the set to 64ths. I agonized over the
decision to spend big money on the make-up collets for maybe 5 minutes and then ordered "made in
Taiwan" types from Enco. With the type of work I do, the difference in accuracy is indiscernible.
I suspect I get more taper from twist in the lathe's bed caused by foundation shifts than from
collets. In other words, "I don't worry about it".

Bob Swinney