Decent 4 jaw recommendations.

[kwackers]

Hi guys,
can anyone recommend a decent 4 jaw, I've got a 'Bison' that came with my lathe, it's 8 inches and pretty massive but fundamentally crap.

The lathe is a D1-3 head and the existing chuck is a matching chuck (i.e. the chuck has no backplate, the pins and register are part of it). I did some tests on it the other day after a part came out 'not right' and it's all over the place, most importantly it can't hold a part parallel to the lathe bed, if I put a straight bar in there and register it then move out 4 inches there's about 30 thou of movement!
It's in good condition too with very little use so I assume it was rubbish when it was made...

So I want a D1-3 chuck around 6-8 inches but of good quality, I wouldn't say money isn't an issue but I'm prepared to dig as deep as I can reach...

So any recommendations?

Cheers,
Steve.

[loply]

Does your chuck just need new jaws?

They are very sensitive to ANY dirt or particles on the register or jaws, if you haven't already then I'd do a real careful job of cleaning it then try it again.

[kwackers]

It's a good point and I'll give it another going over.

When I got the lathe the chuck appeared to be new, no marks and still had a fair bit of the brown gloop they cover them in on it. I did check that things looked to be seating correctly (both the jaws and the register with the lathe) and it all appeared fine but I guess it's worth another look.

[Jasonb]

Thats what I was going to say, are the chuck jaws worn on the faces. The bison chucks are good quality, I have one myself and new 8" would set you back about £500 with the integral mount.

http://rotagriponline.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=222&category_id=242&option=com_virtuemart&Itemid=29

J

[kwackers]

Not cheap then!

OK, I'm convinced a revisit is in order. I'd allowed myself to come to the conclusion that they were simply a bit poo.

Don't know if it makes any difference but I would add the chucks are probably 10-15 years old, the guy bought them and the lathe together (a Myford 254) and it languished in his garage pretty much unused because he never actually manage to retire before he moved on to the big workshop in the sky... (There's a lesson there)
Wear is very unlikely though, like I said the chuck is to all intensive purposes new.

[JohnC]

Hi Steve,
I agree with your original diagnosis - the chuck has had it.  I'm over the mountains in York but at great personal sacrifice I will travel to you and remove the offending item....

Or, have you checked that the mounting faces are spotless before tightening the cams?  A speck of swarf here will throw the chuck out of true.  If you do a search on 'D1-3 fitting' you will come up with all sorts of results, particularly about the gap between the chuck and the lathe.  I have come to the conclusion that there should be no gap whatsoever.  Can you get a 1 1/2 thou feeler in there?  With it being a Bison chuck on a Myford lathe I would expect the fit to be good, so dirt would be my first check.
Rgds,
John

I will still pick up the chuck if you don't want it......

[Jasonb]

I assume the bit of bar you are using is straight??

J

[philf]

Kwackers,

I assume that you've tried a 3-jaw and faceplate on the lathe and they are OK?

When I got my Boxford 1130 (with D1-3 Camlock) the faceplate ran out by about 0.5mm towards the outside. I checked the runout of the spindle nose and to my dismay found the flat face was far from perfect. I made a toolpost grinder and a fixture for measuring the taper and reground the taper and the flat. Everything is now spot on.

I have read a lot of rubbish about camlock noses and their fits - as JohnC says there shouldn't be any gap whatsover between the parallel faces of nose and chuck.

I'm not too far away from you (Marple near Stockport) and if you want to try another chuck or try your chuck on my lathe you're welcome to pop over.

Cheers.

Phil.

[kwackers]

Hi guys,

I did have a look to make sure it was properly seated (and that there was no obvious gap). What I didn't do was try rotating it to see if it was any better in a different position. In the past this has helped but normally we're only talking a tiny bit of difference.

The lathe came with a large number of chucks, small+large 3&4 jaw, self centering 4 jaw, plus face plate and a 'dog' driving plate.

From memory the small 3 & 4 jaws have only a small amount of runout and the faceplate seemed pretty much bang on.
(I know the self centering 4 jaw is out a bit - but I think that's my fault since I machined the backplate.)

I think basically I saw how much the runout was and decided it was so much that there obviously wasn't much point in bothering, combined with a quick google that said "bison = Polish" and I gave up and posted my message. So this evening I'll strip out the jaws and make sure it's all clean in there, then check the rear of the chuck have a nice cup of really hot tea and put it back on, spin it around a bit and find the best place for it to sit and then measure it all again...

(Oh - my rod was only a piece of 1/2 inch silver steel, but I had selected it for straightness. I also rotated it 180 degrees in the chuck but the error stayed on the same side).

Cheers guys.

@Phil, thanks. If all else fails then before I melt it down or wait for a Yorkshire man to collect then I might take you up on your offer.