I have several Pin Vices and have in fact found the collet sometimes too small to hold a larger drill or too large to hold a small one. In those cases the X-acto hadles with the X type collets work well. Especially if I need it for only a few holes and my pin vices are already "In Use".
Is that what you mean Bob?
well, for a while i had no small pin vice collet (i blame the carpet monster) and i would just put the mini bit into a exacto knife and and make shure its straight. dremel solved all those problems though.