Lathe chuck removal

[Curtis RutterParticipant @curtisrutter61973]

[Curtis RutterParticipant @curtisrutter61973]

having now acquired a independent 4 jaw chuck, Im somewhat perplexed on how to remove the current 3 jaw chuck from my Myford ML7. There's lots of hints on removing a stuck 3 jaw chuck but nowhere can I find the "official" way to remove it under normal circumstances, i.e. Where it's not stuck on and the manual hasn't shed any light.

[BizibilderParticipant @bizibilder]

Lock the headstock (maybe by engaging the backgear if the ML7 doesn't have a locking bolt). Put a piece of timber (hardwood for preference) in the chuck crossways. Use a piece a bit over 1" square and a couple of feet long, holding it near the end. Apply pressure to the timber to undo the chuck. If this doesn't work try hitting the timber with your hand. if still no joy then clout the timber with a hefty hammer!

[Gordon AParticipant @gordona]

Myford ML7 lathe Notes on Installation and Maintenance (Publication No 701) states:-

"When removing a chuck (or face plate), do not "yank" the chuck off with the headstock locked with back-gear, but set the headstock for normal back-gear drive, and after placing a piece of hard wood on the lathe bed, pull the spindle round by means of the belt so that one jaw of the chuck or slot in the face plate strikes the wood sharply. The most obstinate chuck is released in this way, and a great deal of load is taken from the back-gear teeth".

It worked for me, good luck and take care not to pinch your fingers between the belt and pulley.

Gordon.

[JonParticipant @jon]

Mine was a bitch not a cats in hells chance by Myfords recommended method, belt slips.

Only way out lock the spindle but wont say how on here, spanner on a jaw and sharp tap left hand thread.

[egaParticipant @ega]

Perhaps it is worth again mentioning Lawrence Sparey's Myford spindle locking spanner (my brief article about my own version of this is behind the clock on the editor's mantlepiece).

[Mike PooleParticipant @mikepoole82104]

Using the back gear to lock the spindle is fraught with danger, any torque or shock applied to the chuck is carried by little more than one tooth of the back gear. If the chuck is not jammed on the nose it may well release easily but if it is stuck hard then think about the load on the poor tooth. Resist the temptation to use the chuck key as a lever as the sockets will break. Try a very large Allen key tightened in the chuck jaws or a bar locked in the jaws to give a lever. At the end of the day a backplate is cheap compared to the damage that can be done to the spindle and gears so unbolting the chuck and machining the backplate away can make economic sense. If the chuck is of the threaded body type then maybe the risk of damage is a bit more worthwhile. It is worth stopping to think where the force you are applying is going, there is usually a key or pin that is going to transmit the drive so shocks and high leverage is going to be applied to some parts that were not designed to take these forces. Locking or jamming pulleys or gears is the only strategy available but just remember that most of these parts can be bent or broken if too much power is applied.

Mike

Edited By Mike Poole on 11/04/2017 22:47:56

[Curtis RutterParticipant @curtisrutter61973]

Posted by ega on 11/04/2017 22:41:17:

Perhaps it is worth again mentioning Lawrence Sparey's Myford spindle locking spanner (my brief article about my own version of this is behind the clock on the editor's mantlepiece).

Have sent you a message

Thanks for all the tips, also looking at a spindle locking handle, would come in handy for tapping and threading

[egaParticipant @ega]

Curtis Rutter:

I have replied to your rmessage.

Edited By ega on 12/04/2017 17:01:22

[brickyParticipant @bricky]

I remove my chucks by fiitting a piece of occtagonal bar in the jaws and use a spanner after locking the headstock.This has also worked on a jammed chuck.

Frank

[roy entwistleParticipant @royentwistle24699]

Bricky How do you lock the headstock on an ML7 ?

Roy ( And please don't say put it in backgear )

[Neil WyattModerator @neilwyatt]

Posted by ega on 11/04/2017 22:41:17:

Perhaps it is worth again mentioning Lawrence Sparey's Myford spindle locking spanner (my brief article about my own version of this is behind the clock on the editor's mantlepiece).

?

[brickyParticipant @bricky]

I have a Super 7 and I don't know if the ML7 has a spindle lock.

Frank

[egaParticipant @ega]

Neil Wyatt:

PM sent re your ?

[Curtis RutterParticipant @curtisrutter61973]

Posted by bricky on 12/04/2017 22:11:59:

I have a Super 7 and I don't know if the ML7 has a spindle lock.

Frank

No it doesn't

[Nick HulmeParticipant @nickhulme30114]

I'll add a useful thread address here simply because I abhor the use of PMs for useful information which should be posted on the open forum where it will be helpful to people searching later rather than providing them with a dead end and some PM references.

 

http://www.model-engineer.co.uk/forums/postings.asp?th=112932

 

Nick

Edited By Nick Hulme on 13/04/2017 08:45:06

[egaParticipant @ega]

Nick Hulme:

Thanks for reminding me of this thread. The reason for my resorting to PM now was that I envisaged sharing with the OP an article submitted for publication in the magazine and wanted to avoid any question of conflict with MTM's house rules.

[HopperParticipant @hopper]

As the owner of an ML7 with a busted tooth on the back gear, I'd second all comments regarding not using back gear to lock the spindle. The 20DP teeth are not very sturdy and the gear is cast iron so prone to snapping rather than yielding.

If the belt slips while using the Myford recommended method it might be worth looking at new belts – if they are over 10 years old they will have gone hard and slippery. It is not usually possible to slip a properly tensioned new V belt by hand.

When I fit the new back gear i will be drilling the extra hole needed to use the Sparey locking tool, though.

Edited By Hopper on 13/04/2017 12:24:57

[Howard LewisParticipant @howardlewis46836]

The chucks on my lathe screw on (but have dogs to prevent then unscrewing when used in reverse).

I have drilled a hole into the chuck, or backplate. Into this Is inserted a piece of round silver steel, which is gripped (not welded) into a boss on a piece of rectangular bar. With the belt tightened, and the retaining dogs removed, the rectangular bar is held with the longer side vertical, and the end hit with a copper/hide mallet. Works every time!

Applying the same technique to a piece of fairly large diameter hexagon, (or square if a 4 jaw) gripped in the jaws should work equally well.

Another possibility would be to cut a piece of wood so that, when resting on the rear of the bed, a chuck jaw makes widespread contact. Spinning the chuck, BY HAND , not power, so that one of the jaws hits the wood, may slacken it. Preferably, the contact between wood and jaw should be as close to the chuck body, as possible.

Howard

[Niels AbildgaardParticipant @nielsabildgaard33719]

If Chuck is really stuck this helps

**LINK**

There are to many broken back gears out there.

[Howard LewisParticipant @howardlewis46836]

It should be taken as read NOT to engage back gear as a means of locking the Mandrel to remove the Chuck.

A friend regularly used to ask me to cut new gears for him until he realised the error of doing this.

With a tight belt, the motor and mandrel ought to provide enough inertia for the "sharp tap" technique to free the Chuck. Once it has slackened a few degrees, it should be possible to unscrew it by hand. If it doesn't. there is something really wrong!

A suddenly app;lied force has twice the effect of a gradually applied one. If you don't believe what my Physics master told us, just draw the graphs!

Is it necessary to advocate a wooden chuck board to safeguard the bed when the chuck does unscrew?

Howard

[egaParticipant @ega]

Posted by Niels Abildgaard on 17/04/2017 07:18:07:

If Chuck is really stuck this helps

**LINK**

There are to many broken back gears out there.

Thanks for this link to a useful-looking tool.

I don't recall Tony Griffiths' website article on this subject being mentioned here – I only chanced on it myself just now – but it is well worth reading and contains a link to a similar tool.

Tony doesn't mention Sparey but he does sell his book!

[Mike PooleParticipant @mikepoole82104]

The gear on the end of the spindle is not keyed by a normal key but a so called French key where a hole is drilled and tapped half in the gear and half in the spindle and a grub screw fitted to key the part together. Any extreme force is likely to cause damage. The bull wheel is keyed by a single woodruff key again perfectly adequate to drive the spindle for normal turning but vulnerable to extreme force. A possibility that I have been mulling over but never tried is to make a thick sleeve and loctite it to the spindle after dismantling, this could be held in a vice with no fear of spindle damage, a couple of flats or use a square bar should minimise how tight the vice needs to be. Now we need to apply some force to the chuck preferably without damaging it. A big adjustable on one jaw is putting a load on the jaw slot that is not what it was designed for but should take a fair force without damage, a bar slid between the jaws again can apply quite a force but again the jaw slots and the scroll are taking the strain, a large Allen key will again put a strain on the scroll. If the chuck has a backplate the the chuck could be removed and a bar bolted to it using the bolt holes for the chuck, this is all a fair bit of work but shouldn't break anything. If successful the sleeve can be removed with moderate heat to destroy the loctite and should not harm the spindle.

Might be worth a try.

Mike

[egaParticipant @ega]

Mike Poole:

Points taken; the link on lathes.co.uk relates to a South Bend lathe where the tool grips the spindle rather than anything keyed to it.

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