Need help with stuck 3-jaw chuck Unimat sl

[darkzero]

I like the freezer idea. Maybe a touch of heat then freezer? I don't understand the channel lock idea. It's off the spindle of course but I think I'm missing something here

Can try either or but don't think both is necessary consecutively. Wouldn't hurt to try I guess. Just throwing an idea out there.

I don't have a Unimat chuck but I do have some import micro chucks that all work the same. On a couple of mine the body extends out the rear. Clamp that in the vise, then turn the ring with pliers.

Or if yours doesn't extend out the rear like my other 2, clamp the ring in the vise & turn the body with pliers.

Again this would be an absolute last resort for me. If there's something that is causing it to bind rather than just actually being very tight, this 200 lb gorilla method may do more harm than good.

(Just took quick pics as examples, again I'd use padding to proect the chuck surfaces if I'd actually resorted to this, avoid if possible)

 

[Deloid]

Thanks everyone. I got it with the use of kroil since this morning followed by a freeze. I think I have a duty to overhaul the entire lathe now.
Dean

 

[francist]

I’m glad you got it Dean.

I was wondering though, would hook spanners give any better mechanical advantage over Tommy bars? I’m asking the question in general to anyone following this thread (I just didnt want to hijack before the OP got his problem figured), maybe some mechanical engineer types?

It seems like with Tommy bars you end up expending most of energy against the side of the holes themselves, especially as they get a little galled around the edges. But with hook spanners the force feels a lot more positive. Or is it just my imagination? Anyone know?

-frank

 

[darkzero]

I think hook spanners may be good to keep around, in cases like this, more leverage for loosening a tight stuck chuck. I believe these types of chucks are used with tommy bars to avoid often risk of over tightening. They shouldn't need to be tightened down really hard. Tommy bars are easier/quicker to use too. Kind of like keyless drill chucks that have holes for spanners, used only for loosening. I have spanners for all my keyless chucks (just in case) but I have ever only needed to use one once.

But good thinking Frank, I never thought to use a spanner wrench for these types of chucks. But I don't use them often & have never had one get stuck. Hmm, thanks for the excuse to buy more tools!

On second thought, maybe I have a spanner that may fit what I have, maybe I'd just need to make a new pin for it to fit my chucks.