Clarkson Chuck – removing the centre

[Gray62Participant @gray62]

   I have a couple of Clarkson autolock chucks which have fairly mangled centres, I have tried various methods to remove these to no avail.

Does anyone have any advice for removing the centres?

thanks in anticipation.

[Gray62Participant @gray62]

[David Clark 13Participant @davidclark13]

Hi There

Hefty press, try a local garage for a hydraulic one.

The Clarkson center I disassambled was a short Morse taper.

It took a lot to move it but it came out in the end.

Big bang as it released.

Then you can regrind them in a cutter grinder.

 

regards David

Edited By David Clark 1 on 20/08/2010 16:12:37

[Alan Parker 1Participant @alanparker1]

I removed the centre in one of mine recently by supporting it on something really solid (NOT) the back of your vice ! I used a thick concrete slab, and then by using a heavy lump hammer and a well fitting pin punch give it a heafty blow with the hammer and it will come out of its short morse taper. DON’T forget your eye protection for safety !

[Gray62Participant @gray62]

HI guys,

thanks for the advice, but I have already tried both methods, my son put them in a 50T press in his workshop and failed to remove the centres!!, so a hefty blow wiht a 14Lb sledge was really a gratifying but in realiity a uneventive attempt  at removing the centre. These centre have been in place for a very long time and I suspect will be very difficult to remove without some extreme persuasion.

 

I think it is time for extreme measures, I’ve got nothing to lose as I have a number of other chucks ( very fortunate to acquire several in a workshop clearance deal) so brutality may prevail, but thanks for the suggestions.

 

cheers

 

Graeme

[John OlsenParticipant @johnolsen79199]

I haven’t had to remove one of these centres, but have had a bit of experience with stuck things. If just pressing won’t work, don’t get too brutal too quick. Sometimes a few cycles of heating and cooling to moderate temperatures will help persuade things, especially if you are able to get it warm and then try applying a bit of force. Sometimes gentle tapping over a long period will give things the message.  Patience can sometimes work wonders, and if it doesn’t , well maybe you can spark erode the offending centres away!

[Gordon WParticipant @gordonw]

I don’t know about your chuck, but the advice above often works. If you can , try freezer spray on the centre. When warm put into parrafin bath ,and hope it wicks up.

[Chris TriceParticipant @christrice43267]

I’m going through the same pain right now. I’m damned if i can get the centre out. I’ve tried pressing, the hot/cold treatment, nothing seems to work. I now have the problem where I was using a length of silver steel to drive out the centre which has now belled out at the bottom so much, I can’t extract it. Argh!!!

[Steve GarnettParticipant @stevegarnett62550]

I spent a ‘fun’ three hours parting a Clarkson collet chuck pin earlier this year. Tried all of the above, and soaking it in the remains of the Plus Gas (can you still get this?) but what finally shifted it was the sledge hammer and the really solid base. It’s the inertia and really rapid transfer of energy that does it – this is what a 50 ton press simply can’t achieve – unless it’s dropping 50 tons at the speed of a sledge hammer straight onto your chuck, and I don’t want to be anywhere near that when it happens…

[adyParticipant @ady]

If a 50T press wont move it then its time to bring out the blowtorch.

 

Heat and cool it to extremes(as far as is sensible) a few times.

 

edit:

A sledgehammer  on a concrete base is more fun though, and a lot faster.

….set it up and….bam!

 

(whilst wearing eye protection of course)

Edited By ady on 02/11/2010 10:45:46

[adyParticipant @ady]

  Do any heavily laden freight trains pass through your local area?

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, another technique you can try is to get the pressure on it with the press and then heat the body with the pressure is still applied, preferably with a high heat hot air gun. Be ready for a big bang.

 

Regards Nick.

Edited By Nicholas Farr on 02/11/2010 11:30:10

[Chris TriceParticipant @christrice43267]

Tried that with a blow torch. Didn’t touch it. Next stop, the sledge hammer. Wish me luck.

[Gordon WParticipant @gordonw]

I’ve never dismantled a Clarkson chuck, but plenty of tight shafts, bearings, king-pins etc. A good, hard and fast whack with a heavy hammer, on a good solid mandrel and placed on a good solid base, so the energy goes thru’ the shaft to be removed, will almost always move it, without damage. It is my impression that a sort of wave is set up in the parts and allows a clearance to develop, but I’m open to ideas.

[David Clark 13Participant @davidclark13]

Having once removed a Clarkson centre, a single blow will not do it.

It took a long while and only succeded by using a 5 ton hand press and then not at the first attempt.

It did come out with a mighty bang though when it did come out.

I think it was a shortened 1 Morse taper when checked which made it easy to regrind in a cutter grinder.

regardsDavid

 

[Keith LongParticipant @keithlong89920]

Hi

Just a thought – I’ve never tried this on anything myself, least of all a Clarkson chuck -  but if the back of back of the chuck was filled with grease or oil taking care to get all the air out and then a high pressure grease gun with a suitable adaptor fitted to the open end to pressurise it might that have the desired effect. If necessary try the blowtorch on the other end as well while everything is at pressure – but minimise any residual airspace before you start and have something to hand to catch and mop up any flying grease/oil. My side lever grease gun can generate something over 5000psi from memory.

Keith

[Chris TriceParticipant @christrice43267]

Can anyone suggest anywhere I can get a replacement centre from?

[Chris TriceParticipant @christrice43267]

Having shelved the offending chuck through sheer frustration, today I at least managed to remove the jammed piece of silver steel rod I’d been using as a drift by threading the end that was sticking out a running a nut down it to draw it out. So three weeks later, I’m right back where I started. Maybe the conical point on the centre isn’t as bad as I first thought it was?

[David Clark 13Participant @davidclark13]

Hi There

How about filling the chuck with oil and screwing a bolt in.

Sort of inbuilt hydraulic press.

regards David

 

[Anonymous]

Chris,

 

I believe it is still possible to buy centres from Clarkson, or their successors, for some models of chuck. If you’re interested I’ll find out the details from a friend who tracked them down in an attempt to get a new centre for his old style ‘C’ chuck. They did send him one, but it didn’t fit. In the end I made him a replacement from silver steel.

 

Regards,

 

Andrew

[Chris TriceParticipant @christrice43267]

Thanks Andrew, I’d appreciate it. If I can just get the old one out, I’m fairly certain there’s enough meat to clean it up with a light regrinding.

 

David, that thought occured to me but at the sort of pressures needed, I don’t think the threads will seal sufficiently well. Before we go the press route, I’m going to try putting a short length of hardened steel rod inside and then screw in a new high tensile 7/16th UNF bolt to push against the rod making use of all the thread in the body so as not to strip anything too easily. I’m not hopeful but worth a shot.  BTW, I live in Petts Wood just a few miles from your magazine offices.

[Ian S CParticipant @iansc]

David you got there before me, I was looking at my chuck the other day in regard to this thread, and thought perhaps if one put some gease down the hole, then a bit of rubber for a seal, then screw in a good fitting bolt, but maybe the thread is a bit coarse, someone else can work out the pressure developed.Ian S C

[David Clark 13Participant @davidclark13]

Hi There

How about a bolt in the end, sealed with something and a finer thread through the centre of the bolt to use as the hydraulic pressure source?

regards David

[Nicholas FarrParticipant @nicholasfarr14254]

Hi David, your recent idea may well work. You could perhaps use thead locker solution to seal the bolt in, which should be easyly rermoved afterwards. I would choose a fairly longish bolt and longish threaded bolt as the plunger, whith as finer thread as possible, and fill as much as you can with hydraulic or extrem presure oil. I think you will still need a close fitting sealed plunger though, to stop the oil leaking out. You could always use a larger piece of BMS round, say EN8, and turn it down and thread it to fit, and then make a chamber/plunger affair at the other end. The reason for a longish plunger bolt would give you a bigger displacment area on a small cross sectional area which would give you more pressure on the bit you are trying to remove.

 

Regards Nick.

Edited By Nicholas Farr on 19/11/2010 10:36:32

[Chris TriceParticipant @christrice43267]

It would definitely need a seal. The advantage of oil over grease is that you’ll be hard pressed (ouch!) not to get some air inclusion with grease. If the bolt going in can be turned so that the nose reduces down to match the narrow body bore…..

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