# Regrinding lathe Chuck Jaws



## terry_g (Mar 16, 2021)

Over twenty five years ago I bought A Southbend 10K lathe. One of the sets of jaws was missing for the 3 jaw chuck so I bought a new chuck for it.
I paid almost as much for the chuck as I paid for the lathe. I had a few options but I bought a quality chuck made in Poland.
I remember cringing at the price when I bought it.
About twelve years ago I sold the Southbend and bought a Chinese 12 x 36 lathe. I swapped chucks and gave the new
owner of the Southbend the chuck that came with the Chinese lathe which was also a decent quality chuck.

A while back I was making some heavy duty washers for a gear puller. I sawed four 3/8" pieces off a chunk of 1 1/4"
round stock and chucked all four of them in the lathe to drill them. When the centre drill hit the first washer it spun in the chuck.

I took some pieces of scrap aluminium from an old cleaning rod and made spacers so I could tighten the chuck jaws with them still open.







I attached a Dremel die grinder to the tool post using a 3/8 key and rubber bands made from an old motorcycle tire tube.






I fed the grinding wheel back and fourth on the chuck jaws grinding very lightly for the better part of half an hour.
I put some Play Dough at the back of the jaws to keep the grinder grit out of the scroll plate.
Once I was done I took the jaws out and cleaned the chuck and jaws well.


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## Tom Kitta (Mar 16, 2021)

I re-ground all of my Chinese 4 jaw chucks after getting them - they were crap from the factory - now much better but still not great. I also got a Chinese 6 jaw chuck I need to regrind in  similar fashion - brand new. I have to make a video of it being about 3x less accurate then 40 year old Bison 3 jaw...


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## DPittman (Mar 16, 2021)

terry_g said:


> Over twenty five years ago I bought A Southbend 10K lathe. One of the sets of jaws was missing for the 3 jaw chuck so I bought a new chuck for it.
> I paid almost as much for the chuck as I paid for the lathe. I had a few options but I bought a quality chuck made in Poland.
> I remember cringing at the price when I bought it.
> About twelve years ago I sold the Southbend and bought a Chinese 12 x 36 lathe. I swapped chucks and gave the new
> ...


Wow a low tech simple way of doing things, I love it! I'm a bit surprised that the Dremel tool mounting gave precision results.


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## terry_g (Mar 16, 2021)

The Dremel fit into the slot in the tool post tight and did not move. 
I had a lot of rubber bands holding it and I ground very lightly.


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## boilerhouse (Mar 16, 2021)

That's genius.  I have a chuck with worn jaws.  This looks like a viable repair.


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## 6.5 Fan (Mar 17, 2021)

Looks a bit like a set up i saw on a u tube vid a while back, He made a bracket to hold a little better quality grinder.


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## Swharfin' (Mar 17, 2021)

On my Dremel the thread under the plastic nut on the tip is 3/4' unc, I cut up a pc of 1" key stock and threaded a hole to clamp in the tool post.
Great idea Thanks


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## RobinHood (Mar 18, 2021)

I have seen this method before, people seem successful with the Dremels (or equivalent).

So you figured that the jaws on the Bison chuck were bell-mouthed?



terry_g said:


> I sawed four 3/8" pieces off a chunk of 1 1/4" round stock and chucked all four of them in the lathe to drill them. When the centre drill hit the first washer it spun in the chuck.



You put all four of them in the chuck at once?

Putting multiple pieces of cut stock in either a vice or a chuck does not usually work out well. There is enough size variance that there is bound to be a gripping issue.
One way to somewhat mitigate the size difference is using a soft material shim between the gripping surface and the part. Something like heavy cardboard, paper, brass/aluminum welding rod, copper wire, etc. works. It will deform over the largest dimension, while hopefully providing some grip on the smaller part as well.


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