On Dec 20, 4:45*pm, Jim Wilkins wrote:
On Dec 20, 1:35*pm, "Bob La Londe" wrote:

...
...There are a number of small inexpensive
chucks out there, but they all have a tapered shaft....
For example
http://www.harborfreight.com/cpi/cta...temnumber=4486
...

The arbor screws into a 12mm x 1.0 tapped hole in the back of the
chuck.

jsw

I wonder if you could bore out that hole and tap it to mm 22 x1.5.
Then you could use the chuck in place of the ER16 collet nut. Still
you might have problems turning the chuck. I'm not sure how robust
the Taig mill head is.