View Full Version : drill chuck in end mill holder

12-16-2005, 09:16 AM
Hi, I've got a mill that takes NMTB 40 tooling. Problem is that the jacobs taper to NMTB 40 adaptors are really expensive. On the other hand, end mill holders are cheap. What I am thinking about doing is getting a couple jacobs taper to straight shank adaptors(3/4"?) for my drill chucks and using end mill holders to hold them. I will probably grind a flat on the straight shank to engage the set screw. Adding an extra layer of tooling probably won't help accuracy but if I care about that I won't be using a drill chuck anyhow. Is this going to work ok or is there something that I am neglecting??

12-16-2005, 09:26 AM
Sure, it will work. One of the big downsides is the fact that it will put the chuck outboard of the spindle vertically a few more inches. If you can live with loosing some verticle space, go for it.

12-16-2005, 10:45 AM
If you can put the straight shank in a collet, it may be a little more accurate and reduce the overhang compared to putting it in an end mill holder. Either way, you should be okay.

12-16-2005, 12:20 PM
Keep an eye on Ebay, those 40 taper adapters show up pretty often.

Herb W
12-16-2005, 12:28 PM
Was thinking of doing the same thing, but a couple of 40 to morse taper adapters came with my mill so I'm going to try using those. That way I can use the same drill chuck & mt arbor for lathe & mill.