4 Jaw Thread Damage

This topic has 7 replies, 6 voices, and was last updated 10 September 2015 at 20:50 by woody1.

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9 September 2015 at 21:10 #203746
woody1
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@woody1
Evening all,

Been a while since I have used the site or my workshop due to studying.

I have however completed and have woken up my Myfor 3'' 1/8'' out of hibernation.

Exactly as I left her but I do have a problem which I would much appreciate advice on solving.

Attached are a couple of images. The first initial threads of number 4 jaw are damaged which Im not sure how to remedy. Was thinking of turning out a tap but not sure of the thread specs? Its not a new chuck by any stretch, I have however put considerable time into machining a back plate. 5'' chuck by my reckoning the labelling is, THE BURNERD, MADE IN ENGLAND.

cheers guys,

David.

Edited By woody1 on 09/09/2015 21:11:40
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9 September 2015 at 21:10 #24104
woody1
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@woody1
9 September 2015 at 23:36 #203758
V8Eng
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@v8eng
Rotagrip are a good source of chuck spares, might be worth contacting them.

http://www.rotagriponline.com/index.php?option=com_virtuemart&page=shop.browse&category_id=33&Itemid=29

Edited By V8Eng on 09/09/2015 23:42:32
10 September 2015 at 05:26 #203767
Hopper
Participant
@hopper
If it is just those first two threads in the chuck body you are worried about, a gentle fondling with a small Dremel tool fitted with a small stone should smooth them out ok.

Or a touch up with a thread file might do the job too. You would need one with the teeth on the end for doing internal threads. Being a Burnerd chuck, I would expect the thread to be a Whitworth form.

I don't think you would have much luck with a tap because of the gap in the thread spiral. Although, a spiral-fluted tap may do the job.
10 September 2015 at 08:13 #203776
Neil Wyatt
Moderator
@neilwyatt
Or a diamond file.

Neil
10 September 2015 at 10:19 #203790
Brian Wood
Participant
@brianwood45127
Or use a matching bolt with a little grinding paste on it and gently working it back and forth.

I surely don't need to advise cleaning it all very thoroughly after such treatment

Brian

Edited By Brian Wood on 10/09/2015 10:20:16
10 September 2015 at 12:04 #203799
daveb
Participant
@daveb17630
The 4" chuck screw threads are usually 1/2" BSW. You should be able to clean up the damaged thread with a Dremel with a small grinding wheel, one of their standard shapes will do it. Alternatively, if you have or can borrow a suitable tap, you could clean it up with that, you will need to fit the jaw to support the tap but take care not to run into the fork that goes around the screw.

Dave
10 September 2015 at 20:50 #203851
woody1
Participant
@woody1
Cheers for the advice guys.

I would have used my dremel but I left it in france! Spent about an hour with a file no joy so went shit or bust! Ground a taper on one of the jaw nuts in the lathe (couldn't be bothered turning a taper) ground a single groove like a tap and it worked a treat. put the make do tap through all four as they were a bit stiff and now I have a perfectly perfect chuck

David.
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