# Help please - Rohm keyless chuck



## AES (25 May 2015)

I have the above Rohm "Supra" (3 mm - 16 mm) model 3 jaw chuck fitted to my pillar drill. It's a lovely bit of kit, runs very true, and I keep it scrupulously clean.

BUT, it's a keyless (which I've never liked all that much - old-fashioned me I suppose), and even when brand new, about 7 or 8 years ago, I needed to use a pair of thick gloves to tighten up any size drill well enough that it would hold for any length of time. As time has gone on it's got even more difficult to tighten up properly on both round and hex shank drills, and now I have had to resort to using a large open-ended spanner on the two flats just at the top of the chuck to tighten up. Recently it's got to the point that even with spanner tightening the drill slides gracefully down out of the chuck every time I stop the machine (whether I've finished drilling or not!).

Frankly it's driving me potty. I've had the chuck out of the pillar drill (but have not removed the MT 2 adaptor from the chuck) and cannot see any way of adjusting the gripping movement of the jaws. I also cannot see that any one of the jaws is moving ahead of/behind the other two when tightening.

As said, it's a lovely bit of kit, was very expensive (for a hobbyist) and runs perfectly true, so I really do not want to replace it. As far as I remember there was no "manual" with the chuck - I don't have one now anyway, and I haven't found anything on "t'internet". So does anyone know if there is any way I can adjust (tighten) the jaw closely mechanism please?

The tightening problem apart I certainly don't want to replace this chuck.

TIA
Krgds
AES


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## CHJ (25 May 2015)

Is this of any use?
A copy of the service manual (PDF)

Any lubrication at all finding its way into these seems to cause problems.


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## woodpig (25 May 2015)

Not stripped one of these myself but I've heard it's easy to loose the balls inside if you're not careful. You could send it to Rohm for service.


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## AES (25 May 2015)

Thanks very much CHJ! I searched & searched and couldn't find anything on their web site - and yours is in English too, brilliant! I'll have a go at it tomorrow.

Thanks for the tip woodpig, I'll be VERY careful with my balls when stripping it. :lol: 

Once again, UKW comes up trumps.

Cheers folks

AES


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## AES (25 May 2015)

As a P.S. to my last, for CHJ - thanks for the tip re lub. I may well have got something down inside there, though I have been careful about that and seldom remove it from the pillar drill. (I normally use light mineral oil similar to commercial "3 in 1", or as I'm sure you and I know it, OM15 for all those sorts of jobs).

Thanks again.

Krgds
AES


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## AES (27 May 2015)

Thanks very much CHJ & woodpig. Using your manual CHJ, I made a "girt big" round gripping block out of 2 bits of scrap pine about an inch plus thick, gently clamped the whole chuck up in the vice and carefully unscrewed the chuck as per the manual.

It seems my problem must have started with my latter times of tightening it with the two little spanner flats on top of the chuck because the whole thing came apart very easily - it was clearly too loose. And YES woodpig, you're dead right, one has to be VERY careful with the jaws and the balls - thanks to you I was ready for the near explosion!

As I'd hoped there was very little wood dust (and no metal swarf) up inside the inner taper and/or on the outer surface of the jaws but I cleaned them off with dry clean kitchen roll anyway. There was however a little oil on the inside thread which I therefore cleaned off at the same time, as per your remarks.

Reassembly was easy (WITH the manual!) and as I'd marked the three jaws with fibre tip pen before disassembly, getting everything back together correctly was a cinch. This time I made sure the main body was tight, WITHOUT going berserk.

The whole job took perhaps an hour, start to finish.

Result is a chuck which is still concentric (within the tolerance of my cheapo metric lever-type DTI, as measured against a length of 10 mm silver steel) AND even better, it now grips drills without me having to do Tarzan impersonations.

Thanks a lot Gents, as ever, UKW covers it all.

Krgds
AES


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## woodpig (27 May 2015)

Glad you're sorted and didn't loose ya balls! :lol:


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## AES (27 May 2015)

Nah, I'm always VERY careful with me balls woodpig!

 

AES


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## jonn (3 Jun 2015)

Just got a Röhm 1 -13 mm keyed chuck for my metal lathe, and I had forgotten how crappy they are when it comes to holding drill bits, - or anything really. Simply can't tighten it enough. Also got a Diesella 1-16 mm for the milling machine, and besides from being less expensive, it also holds drills still. And precision is fine. But since mill use R8 spindle and lathe MT3, I'll have to get another. And use the Röhm for a sinker when I get the boat on the water! Diesella is Danish by the way.


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## AES (3 Jun 2015)

That's interesting jonn. I've never heard of Diesella before.

I must say that my Rohm is excellent in all respects apart from always being a bit weak in the "gripping department" from the word go - but it's OK now, since I did the "service" described above. Wonder how long that'll last though.

Personally I've never liked keyless chucks, even on battery drills, but must admit that at least there the convenience of no key when you're doing jobs outside and around the house outweighs the "problem" of having to use a key. But on the bench, or lathe (i.e. with a fixed tool) I go for a chuck with a key every time. In fact it was only because that was all he had on the shelf that I let the local dealer talk me into the keyless Rohm in the first place. Bloody expensive, but OTOH, lovely and accurate and with a little bit of care it'll easily outlast me (I've only got 30 years to go to reach 100!) :lol:

Krgds
AES


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