Can anyone recommend an accurate and physically small 1/2" drill
chuck?

My milling machine doesn't have much Z-axis space, so I hoped to
improve things by buying a set of screw machine drill bits along with
what I hoped would be a small drill chuck. But, the 1/2" Jacobs "Ball
Bearing Super Chuck" that arrived yesterday is massive, about the size
of an ordinary 3/4" chuck.

I chose this particular chuck because the literature claims "The
world's most accurate key-type chuck."

I have a salvaged 1/2" Jacobs chuck that is nice and compact and I
expected to get something of similar size. Was I ever surprised!
I'd use what I have, but it has a threaded mount and is getting
somewhat tired.

My catalogs show a conventional Jacobs and a Rohm, key type. I don't
know which one will eat up the least Z-space. If any of you know
which of the two is shorter, or, if you know of another brand of 1/2"
chuck that would fit my needs, I'd like to hear about it.

TIA

Orrin

I'd more consider getting a series of chucks rather than just one. Yes, you
do get more "precision" with a single chuck but if you use a smaller chuck,
you get that much or more accuracy with the smaller chuck that just holds
the drill on the larger size of the range.
I've always seen that the Jacobs style chuck to be shorter than the Albrecht
style of chuck.

--
Bob May
Losing weight is easy! If you ever want to lose weight, eat and drink less.
Works evevery time it is tried!