I am thinking of purchasing a set of collets. Other than cost, is there any reason to purchase ER 32 over ER 40? It looks like the 40 covers a wider range of sizes with no downside (other than cost). The second question is if they cover a continuous size range, why would you buy Imperial over Metric (or vice versa)? For example, http://www.ctctools.biz/servlet/the-49/FULL-ER40-COLLET-SET/Detail is $14 cheaper than http://www.ctctools.biz/servlet/the-300/FULL-ER40-COLLET-SET/Detail even though they cover the same size range.
Brian
Brian