Re: [CAD_CAM_EDM_DRO] jacobs chuck question

> My jacobs chuck just popped out of my mill. (ruining a part of
> course). I can see that it looks like a tapered press fit. Is this
> normal? How can I prevent it from falling out again. does anyone
> have any experience with these?
> Thanks in advance.

Yes, they are usually press fit onto an arbor that fits the mill
spindle (R8, 3mt, whatever).

* make sure the tapers are really clean. Replace the chuck or arbor
if the taper is scored

* consider using a chuck with a larger (diameter) taper - they come in
avariety of sizes for a given chuck capacity. For example, a JT6 is
larger and should hold better than a JT33.

* never use a jacobs chuck to hold anything that will have any side loads
(especially never try to hold a milling cutter in a jacobs chuck!)

* use a collet for larger drills if you have one of the right right
size - it will be centered better anyway. Also use one for things
like hole saws and radius cutters

Chris

--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
http://www.mdc.net/~stratton
NEW PHONE NUMBER: (617) 628-1062 home, 253-2606 MIT