Camlock D1-4 chuck won’t come off

[RobinParticipant @robin]

[RobinParticipant @robin]

I bought a new Crusader deluxe lathe from Chester and it all looks fixable apart from changing the chuck

The D1-4 Camlocks lack the alignment marks.

Two of the locks turn through 180, the other only manages a reluctant 90 so I think I know where the problem is.

A web search reveals that out all the D1-4 user, English speaking world I am the only one suffering this problem.

I have removed the spring detents.

No answer to the Chester phone so It seems I am on my own until Monday. I don't want to get too vigorous because I don't want it to become my fault.

I hear they are dropping like flies oop North so I need to get this fixed before they have all gasped their last

Perhaps there is a wrinkle I am unaware off, a D1-4 trick to make it behave?

[Alan Waddington 2Participant @alanwaddington2]

On my Colchester even when the locks are disengaged it can take a smack with a soft faced mallet for the chuck to pop off

[Henry BrownParticipant @henrybrown95529]

As Alan said, the chuck needs a gentle tap on the jaw side, all three of mine respond to this treatment. I'd be a bit concerned about the lack of marking though especially if it doesn't have the 0 0 marks to be sure it was put back in the same place.

[Clive FosterParticipant @clivefoster55965]

Robin

Sounds like one camlock pin is either screwed in too far or not far enough. Either will prevent the lock turning far enough. Difficult bit is identifying whether the lock is only moving out of the neutral opening position in the lock direction or unlock direction.

Even with a properly set up camlock its often necessary to thump the chuck lightly with the heel of your hand to get it to release. Sometimes turning right past the unlock position until it hits end of travel is also necessary before the hand thump. I imagine this is neccessay if the pcd of the studs or angle between them is a little bit different to the spindle mount. Presumably moving to the other extreme helps re-centralise the suds to gain clearance.

My"best" chuck is on an import backplate and needs the turn back and heel thump technique to release easily from my Smart & Brown 1024. The 4 jaw is original and the backplate studs a re clearly a smidgin better aligned so it just releases. on unlock. Same with the D1-5 set up on my P&W Model B whose chuck and backplate fittings are all Western. Although the best chuck on that, a new old stock Polish made Bison, likes a gentle thump sometimes. that is due to the superb fit on the spindle taper.

Clive

[RobinParticipant @robin]

But what when a lock refuses to turn?

Should I be able to remove a lock once the detent is out?

What could stop a lock turning?

I am not having a lot of luck lately. I might need to pop down the Catholic Church and light a candle, mumble an Ave of two.

[RobinParticipant @robin]

I have a foot long, 1.5" diameter iron bar in the chuck and running back through the spindle. I have given it a couple of encouraging taps to try and free it but I don't want to make it worse.

The chuck will move forwards the thickness of 2 sheets of paper and that is my lot

Once moved two locks are loose, the third is jammed tight

Edited By Robin on 21/11/2020 13:23:42

[Henry BrownParticipant @henrybrown95529]

Did you try locking the two loose ones up and trying to loosen the tight one first, mine go about 100-120 degrees anti-clock from locked to free. I think I'd take the bar out and put a wide piece of wood on the bed as a safety belt. Sorry if I'm covering stuff you have tried…

[RobinParticipant @robin]

Hi Henry, I will try anything.

Bar out, wood in place, tight on two, number 3 still won't move

[Clive FosterParticipant @clivefoster55965]

Robin

Basic operation of a camlock system requires the pins to be sufficiently loose on the threads so that the lock can firstly pull the pin back then force it sideways against the bore in the spindle end jamming everything up nice and tight.

A lock jammed like yours is likely due to the pin being pushed sideways against the wall of the bore before the cam has moved far enough to complete the pull back.

Its possible that exerting force in the unlocking direction whilst thumping the backplate sideways more or less opposite the pin will generate enough vibrations to let things slowly release. Trouble is the loose fit of the pin in the thread makes for very inefficient vibration transfer.

Hitting the face of the chuck will do nothing, it may well make things worse and is, in any case bad practice despite being advocated by many experts as a way of releasing a tight chuck. Hitting something held in chuck jaws will not help either.

If its irremediably jammed the chuck will have to be removed from the backplate and the pin cut out by holesawing or similar techniques so it can be directly attacked by twisting and pulling. Probably just fall out then!

Lathe spindles have been ruined by ill thought out attempts to remove stuck pins!

Personally I'd be on the phone to Chester first thing Monday and tell them to replace the whole thing sharpish.

But I'm old enough, ugly enough and grumpy enough to be well past trying to sort something faulty from new.

Although it appears to be a simple issue camlock problems are anything but minor. The whole accuracy and safety of the machine depends on the chuck fitting working properly.

Clive

[peak4Participant @peak4]

They shouldn't turn a full 180° to release.
If the pins are set up correctly in the chuck (they are adjustable) then open to full lock should be 90°+, but less than 180°; at mentioned above 120°ish sounds about correct.
If you over release the cams, then they may re-lock slightly and prevent you moving the chuck.

It might be that the one at 90° has actually released OK, but the other two are now locking it.

Where other folk have mentioned tapping with a mallet, that's to release the chuck from the short taper, but if you've got space for a couple of sheets of paper, that wasn't there when everything was tight, then you've already released from the taper and it shouldn't need hitting.

Bill

Edited By peak4 on 21/11/2020 14:55:55

[RobinParticipant @robin]

I just fetched it. I found a picture of the cam and decided there wasn't much to stop me so leant on it hard as I could.

It let go suddenly sending me stumbling backwards into the engine hoist which suddenly needed supporting to stop it falling against the lathe.

Quite exciting for a moment.

All apart now, SWMBO wants me to walk the dog before the diagnosis and repair. I think one pin on the chuck was screwed in one turn beyond the depth ring. If true then Clive wins the coconut, pictures when I get back

[RobinParticipant @robin]

Unscrew the errant camlock pin one turn and suddenly it is no longer 1mm shorter than everyone else.

Understand that the spring index hits a dent so I can feel when the camlock is ready to receive or lose a chuck. No mark required.

Put it all back together, fit the chuck, remove the chuck, replace the chuck and it is back to running sweet and true.

What a relief. Tomorrow the 4 jaw and then the faceplate

[DC31kParticipant @dc31k]

Glad it has worked out. Hopefully I am not teaching you to suck eggs, but are you aware that the spindle should have a mark on it somewhere between two of the cams and that everything that attaches to the spindle should also have a mark on it which should align with the spindle mark?

This is to ensure that every time you mount a particular item, the same pin goes in the same hole, so that if you have tuned the pin lengths to get correct locking, it will always repeat.

Type 'camlock stud fiddling' into Google and save the document by Robert Bastow.

Edited By DC31k on 21/11/2020 19:01:31

[old martParticipant @oldmart]

Glad to hear you got a good result. As there are no marks on the mating parts, it would be a good idea to check the run out in all three positions and put permanent marks on the best one.

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