Help with chuck jaws please

[paul]

I took the jaws out of my Clarke CL300 3-jaw chuck tonight and can't get them back in! I had the same problem once before and it took me about an hour to get them back in place.

The 'manual' says take the numbered jaws (1,2 and 3) and refit them, clockwise, in the same sequence but they just won't go. I can 'unwind' the chuck and click the jaws into place but they just refuse to tighten beyond a short distance.

I wasted a good 40 minutes attempting re-assembly tonight. Help!

[jont]

Three jaw chucks usually have one set of internal jaws and one set of external jaws. Each set will only fit the chuck in the intended direction. Is it possible you are trying to fit the internal jaws as external ones or vice versa?

[Tel]

look down into the no.1 slot untul you just see the start of the scroll 'thread', back off a little, put no 1 in and keep a little downward pressure on it while you advance the scroll enough to pick it up, move to no 2 slot, carefully advance scroll untill the start is just visible, as before, and ditto repeato. Repeat for no. 3

[houstonceng]

Check that you're putting the jaws into the correct slot. Some chucks don't like it t'other way 'cos the slot/jaw combo for each has been matched.

Another thought, I had a chuck - purchased with the lathe complete with backplate already fitted - that liked to be tightened onto it's back-plate after cleaning a little at a time (as you should). Tighten up one bolt too much and it'd let you know by making two of the jaws almost impossible to move.

Finally, I checked the "as bought" register depth on the backplate and realised that the clearance was under the bolting face not the other way around. A lttle machining on the plate and no more probs.

[houstonceng]

Hey Paul

BTW. My jaws are fitted in an anti-clockwise sequence because the chuck-key turns CW to tighten the chuck (onto external of job) and the gearing is at the back of the scroll so - - scroll goes ACW

Just a thought

Andy

[SteveW]

Paul,

I bit like Tel's solution but I take the scroll end just past the slot, push in the correctly numbered jaw (1->1, 2->2...) and turn the key backwards waiting for the reassuring snap as the jaw drops in. Immediately reverse the scroll direction to secure the jaw using one turn of the key but not enough to move the scroll end past the next slot.

Move on to the next slot and carefully advance the scroll until the end appears and then STOP. Push in the next jaw firmly and again reverse until the snap-in occurs. Repeat for number three. By putting them in in order 1, 2, 3 they'll all meet in the middle at the same time.

The point about inside/outside jaws is well made. Whichever set you use you'll notice that each tooth on the jaw's internal rack is flat one side and convex the other. The convex has to point away from the lather centre line.

Q.E.D.

[Shawki Shlemon]

Look at the numbers 1 2 & 3 on the chuck , I think they are anti clockwise . Try again .Good luck.

[abby]

After fitting the jaws into the slots I put a large rubber band around all three ,or if the chuck is small enough my fingers ! I then "undo" the chuck watching each jaw click , when no.1 clicks - tighten. If the jaws are sticking after first starting ok and you have changed the jaws before it is likely that there is a bit of swarf in the scroll. Even if you have the jaws in the wrong slots or have mixed inside/outside jaws they should still tighten - they won't centre. I have on occasions used 1 external and 2 internal jaws to hold awkward shapes.

[paul]

Thanks all... DOH! I didn't realize that the slots were numbered too (and I don't think the manual says that they are, it just says line them up 1,2,3 and re-fit clockwise in that order). I'll give it a try this evening and apply all these tips you've given me

[Tel]

If you turn the chuck key clockwise to tighten the jaws. you will need to install the jaws anti-cclockwise, as has been said. The slots, in any case, should be numbered

[paul]

Problem solved - thanks all

Tel you're right (Karma + 1!), the jaws need to be installed anti-clockwise. I could see the '1' stamped in it's slot but '2' and '3' are indistinguishable, it was just a case of swapping those two around till it worked. I think I'll throw away the 'manual'!

[Tel]

Pleased we could be of service ;D

[houstonceng]

Hew Tel

How come you got the Karma after I said Anti-clockwise first ? What's your secret. More hair than me ?

Quote : "It's amazing the good you can do in the world so long as you don't mind who gets the credit"

Andy

[Tel]

I must just 'ave an honest face, oh, and I"m kind to little puppies. ;D

I'lm 'appy to share tho'

[houstonceng]

Thanks Tel

Andy

[Shawki Shlemon]

I think I was the first to tell you about anti clockwise . did you read all the replies ? I am now upset and will stay away for a while .

[paul]

shawki said:

I think I was the first to tell you about anti clockwise . did you read all the replies ? I am now upset and will stay away for a while .

Aw ! Yup I read 'em all and Andy was first to mention anti-clockwise, so he gets the cigar!

[simonwass]

Use a blunt center punch and lightly pop 1 dimple on the outside on the chuck near no. 1 jaw, 2 dimples near no. 2 jaw etc. 10 second job to get all in right place 1st time. The jaws will be number stamped by manufacturer.
Simon

[paul]

Great idea Simon!

[Shawki Shlemon]

Hi Paul
Thank you for the pm .I am thick skinned and I don't get upset easily . My complain was only a joke .Yes ME is a major part of my life now as I have been retired for the last 10 years .