Boxford AUD Chuck Quandary

Evening all, I've had a Boxford AUD for a while now, but very much still a beginner. It originally came with a 4 jaw and 3 jaw Pratt and Bernard. The 3 jaw has only inside jaws which has caused issues with small jobs. I've looked into obtaining outside jaws but was told that as it was a sixties model I wouldn't be able to get a set. I've been given a unused 3 jaw with both inside and outside jaws but the back plate is different to the Pratt item.

Has anyone heard of YAMA? Is it worth making a back plate for this although I'd need plenty of hand holding and I'm not sure I've got the gear to do it, but obviously it would be good learning experience. I tried buying an off the shelf plate but RDG hadn't heard of them and I couldn't find any info on the net so don’t want to go to any trouble and expense unless it’s worth it.

What is the maximum diameter of chuck I could use on this machine, my 4 jaw is larger so would it be better to go for a larger 3 jaw and lastly any recommendations for a budget 3 jaw.

Sorry for all the questions and thanks in advance for any help, which will be much appreciated. I've been dithering about this for too long and I need to get it sorted.

Regards Si

Not heard of Yama chucks. You can get a Boxford backplate from ARC Eurotrade. You only then need to machine the face to suit whichever chuck you go with. You can get a good chuck from ARC also. If you have any problems with it you will get good support from Ian & Ketan. Realistically a 5" chuck is about as big as you want to go with the AUD.

I have a 6" for my AUD but it can be a nightmare with jaw stick out so I have only used it once in several years.

IHTH

regards

Your picture shows outside jaws

I told you I was a beginner.

Perfect Oldiron, thankyou

Simon

Get a backplate from ARC and go for it. Most backplates have enough meat on them to be re-machined more than once for new chucks so, at worst, think of it as practice. You will need to get a backplate as well if you do just go and buy a new-new chuck.

I have a backplate that has worn at least four different chucks, maybe more as at least one set of holes has been enlarged or shifted. I've modified it twice more so far!

A 3 jaw isn't a precision device when it comes to maintaining concentricity when removing and replacing parts so odds are your YAMA will work perfectly well for all normal jobs. Even if it is a bit out when compared to a high end precision version. Being new its going to grip better than an old, worn chuck. Which is much more important.

Hafta say that at the lower end of the market there is a good deal of luck involved in how good and how concentric the chuck is.

I have a cheap, Chinese made, small chuck on a 5C mount bought many years ago back in the days when low end import was a serious lottery to use on a Spindexer. Finish is OK but everything about the design screams cheap-cheap-cheap. Right down to the short 2 1/2 ring scroll. Plugged into the 5C native spindle of my Smart & Brown 1024 its performance isn't far short of the precision Pratt Bernerd the machine normally wears which was something like10 times the price.

Clive

Edited By Clive Foster on 16/02/2022 19:23:42

Simon -

Can I suggest that you might do well to ring Rotagrip in Birmingham who have usually got spare jaws for the standard chucks in stock. Not only that but they know what they've got and will recognise the chuck you have from a few vital dimensions, and be able to match the body to the correct jaws. This can be a bit of a minefield to the un-initiated. Not only must the tee slot be right, but the pitch of the scroll has to match as well. Usual disclaimer applies - but I've never asked for the wrong thing from them.

Standard internal jaws come hardened and ground, they usually need a little bit of gentle fettling to get them to be a nice sliding fit.

Once you have identified the chuck body and found jaws to fit, buy a couple of sets of soft jaws. These can be the secret to all sorts of otherwise difficult holding challenges, and (being soft) are easy to machine to good concentricity in situ. Jobs like turning large flat washers are suddenly a doddle with soft jaws.

HTH, best regards Simon (another one).

My Boxford has a 5" Pratt Burnerd dating back to the '70s. I recently bought a set of soft jaws for it from Rotagrip. Cost about £30. This could extend the usefulness of your present chuck. I think that Rotagrip also sell sets of hard jaws for the PB 3-jaw but you might not like the price.

Edit; typed too slowly.

Edited By Clive Brown 1 on 16/02/2022 19:52:52

Simon if you post your location you might be able to get some local help. As a matter of fact I have several sets of spare jaws of different dimensions if you measure the slot width and the tooth pitch (the distance between one edge of a tooth and the same edge of the next tooth) I'll have a look if I have your inside jaws. Looking at the chuck it's likely to be 1/4" pitch so you'll have exactly 1" across 4 teeth.

Thank you so much everyone, some great ideas and contacts.
I'll make a few calls on Friday regarding the back plates and Simon I'll definitely try Rotagrip for Patt Bernard jaws.

Richard, thankyou for the 'how to' link thats really useful, Simon, Clive,  the soft jaws are a great idea and Pete, I'll measure up tomorrow and if it’s ok with you I'll pm you.

Have a good evening.

Edited By Simon Ricketts on 16/02/2022 20:50:13

Edited By Simon Ricketts on 16/02/2022 20:51:28

Edited By Simon Ricketts on 16/02/2022 20:52:41

Oh yes, and forgot to say I live just outside of Honiton, Devon……

You can fit pretty much any similar size chuck with a recessed back on a backplate.

Edited By Dave Halford on 17/02/2022 13:44:30