HBM lathe chucks

Hi All,

Its been a while since I last posted. I am looking for a 4 jaw independent lathe chuck for my Unimat SL. I have been looking at an HBM chuck (12MM) from RGD Tools.

Does anyone have any experience of HBM tools bearing in mind that its now almost impossible to get parts like this for these lathes.

Thanks

Rob

Hi Rob

I can't answer for this specific chuck but I've found the stuff I have purchased from RDG to be OK. At just under £50 for the one you need I'd say it is worth a go - if you are not satisfied you can always send it back. Bear in mind  you're not going to get Lorch quality at this price!  I have a 100mm HBM self centering 4-jaw which is fine. ( I may well have bought this from RDG but, I'm afraid, can't remember) I do remember buying an adapter for my watchmakers lathe from RDG which had a small manufacturing defect -  a ' phone call to them produced an immediate apology and rapid replacement.

Regards

Norman

Edited By NJH on 12/12/2012 13:31:12

Looking for same chuck.. watching with intrest.

Prob. don't need to remind you ,but you need 12 x 1 not the "usual" unimat 14 x1.

rdgs Jason

At 45mm thats quite a small chuck I think I would machine up a backplate with the 12x1 thread and use a larger chuck. The 4-jaw on my Unimat3 was 60mm and the capacity quite limited.

J

Hi Robert,

I had a similar problem in finding a 3-jaw scroll chuck to fit my Perris (now the Cowells) lathe with an obsolete 1/2" x 20 UNF spindle nose. I picked up a cheap 2.5" 3-jaw with an M14x1 thread, bored the hole out and rethreaded it M17(ish) x1, made up a bush with a matching thread, and then bored/threaded the bush to the desired 1/2" x 20 UNF. Full story here. The same technique could be used to bore out and bush a 4-jaw, though it does require access to another lathe with screwcutting facilities.

A backplate would be simpler, at the expense of a little of the chuck to tailstock distance. I was unable to use one, because the bolts attaching it to the 3-jaw might have fouled the internal scroll. That wouldn't be a problem with the solid body of an independent 4-jaw.

Andy

Hi Robert, Same as NJH, I too bought a 4" SC 4 jaw from them and whilst it is not as good as my Burnard chucks it is very good value for money at about £80.

I can pick hole in it but it is not bad for accuracy -- how long for remains to be seen but you pays you money ! Overall I have been happy with everything I've bought from RDG balancing against the price paid.

Cheers John

Hi Rob,

I have an HBM 3 jaw chuck on my Chinese lathe and have no problem with it at all. I have used it for a couple of years now and find it one of the most accurate 3 jaw chucks I have used. I have used RDG at times with no problem, either with quality or service.

Regards

Terry

Hi

Some time ago I bought a 100mm 3 jaw SC chuck (HBM) from RDG for my rotary table. My experience is similar to others in that the accuracy is good a the chuck seems to be very good value for the price. On the one occasion I had a minor problem with a part I bought RDG were more than helpful and rectified the problem immediately, can't ask for more than that.

Cheers

Martin

HBM 3 and 4 jaw chucks

Good gear, no problems

Hi All,

Thanks for your valued replies. I decided to go ahead and buy one although I agree that 50mm does seem a wee bit small.

Regards

Rob

Hi All,

The chuck arrived this morning. It does appear very well made although I'm a bit concerned that the jaws are 'tight' to turn - should I regrease the threads and if so, can you recommend what grease I should use??

Thanks

Rob

Hi Rob,

It can help to give the corners of the slots in the chuck body and the corresponding parts of the jaws themselves a light rub with an oilstone, to get the jaws to slide more easily in the slots.

Andy

Rob Hi,

I agree with Andy and have had to clean and remove burrs on several new chucks in the past and not all "cheap" ones either. You will be able to decide if it is the jaws not sliding or the screws not turning by removing the jaws (mark them first), remove the adjuster and slide the jaw back into the slot. I have found both issues and a simple de-burr with a stone or diamond file has worked for me.

I have found swarf trapped between thread and chuck body as well as between thread and jaw rack (not Chinese either) but unlikely if all 4 jaws are tight. I have also found with one import chuck that the adjustment screws were full form threads (?) and as the slots were a very nice fit the crests were fouling the jaw rack, a quick clean up of the adjuster thread outer diameter with a bit of emery in the lathe fixed that one.

I am not a supporter of grease on chuck threads as it will attract all sorts of swarf and lead to many similar problems when in use. A good clean/de-burr followed by a quick wipe with a trace of good machine oil keeps my chucks fine.

I am thinking of getting one of these independent 4 jaws for my Cowells but will need to re-machine the thread register as mine is the older 14x1.5mm type. Are the jaws reversible? I can't see from the picture on their site.

Best regards

Keith

Hi Keith & Andy,

Thanks for the info.

I've had one of the jaws out already and it does appear to be reversible but I shall double check.

Regards

Rob

I'd be surprised if the jaws on an independent chuck weren't reversible, Keith. After all, they have a simple plain thread to engage the adjusting screws.

In contrast, the jaws on 3 (or more) jaw scroll chucks need teeth shaped a bit like this: ((((( so they will engage with the spiral scroll. If you try to reverse them, they won't fit, so a separate set of jaws with teeth the other way round is usually provided with the chuck. Of course, there's an exception to every rule; the jaws on the very cheap and cheerful 3-jaw I modified to fit my Perris (forerunner of the Cowells) are convex on both sides, as a compromise.

Andy.

Hi Rob,

First thing to do before removing metal from your chuck - you can't put it back on - is to clean off all of the anti corrosion wax/grease as it is very viscous and can cause initial stiffness. I am also not in favour of grease for the same reasons as above but I use a dry ptfe based high pressure lubricant which does not attract any swarf or gunge.

If this does not cure any stiffness, use the chuck for a while to 'run it in' and if the problem persists only then would I start deburring or otherwise removing material.

On the HBM 3 jaw SC chucks the jaw numbers are usually stamped in the channel on the side of the jaw and the same on the chuck body.  the jaws on a 3 jaw SC chuck are rarely - if ever - reversible due to the nature and geometry of the spiral, the 'teeth' on the jaws are a compromise to accommodate the changing radius of the spiral scroll.

Best regards

Terry

Edited By Terryd on 29/12/2012 15:56:56

Rob, Andy

Thanks for the comments, I also agree that the jaws should be reversible but the shape of the jaw outer ends look square to me rather than tapered to grip when reversed. It looks as if the jaws will not completely centre when reversed and the cowells doesn't have a lot of clearance for jaws that stick out beyond the chuck body. OK if I can keep it within the gap but could be a problem if the chuck or my adaptor is a little long.

Terry, all good comments but I can't agree with not checking and removing the burrs if present or indeed breaking corners if they have been left sharp.. Both faults are quite prevalent on some of the cheaper items available these days and apart from causing tightness and possible jamming, they are very good at giving a false impression of a "good fit". Unfortunately, when production times are tight removal of them is often the first thing "forgotten".

I wouldn't advocate removal of metal from any mating faces and always use a touch of engineers blue to identify the "tight" areas, surprising how often I find them to be in the corners of the jaw slides or even on one chuck from burrs left by cutting the idicator rings in the front face.

I am not complaining as I enjoy the very reasonable prices we can get usable tooling for these days with just the simplist of remedial attention.

Best regards

Keith