I have a vertical mill with an R8 spindle and it seems whenever I used the typical R8 collets the tool eventually slips despite how tight the drawbar is. Sometime just a little over a long period and other times a lot even to the point of slipping out entirely. So, I switched to end mill holders which I think are great. However, they are only available in certain sizes and then I am not sure if they should be used on end mills without a flat. So, I wanted to get opinions on using an ER32 collet chuck such as the one below. I personally have a hard time believing that the runout of the holders that I am using right now is significant enough compared to my skill level, i.e. more errors come from my skill than the small runout. So, I am more considering the ER32 chuck collet for tools that I don't a holder, don't have a flat, drill bits, etc. Just how much better are the ER32 collets over the typical R8 collets or over end mill holders for that matter? Does the ER32 collet hold tight over its entire range? Is the cost justified or would I just be paying a lot more for next to no improvement? Is there something else I should consider?

Thanks

http://www.use-enco.com/CGI/INSRIT?PMAKA=505-2213&PMPXNO=953531&PARTPG=INLMK3

The chuck & collets you linked are very good. ER collets in general are pretty much the best out there. They grip very tightly and compress enough such that you can grip just about any odd-sized drill bit.

The ETM chuck and collets are probably some of the best available. You can get a Bison set for cheaper, but the ETMs are a little bit better. Made in Israel by Iscar I believe. Avoid China at all costs.

By the way, Enco is having a 10% off deal till tomorrow so if you plan on buying that set, PM me and I'll give you the code.