Remove Seized on chuck ??

[micktoon]

Hi all , I am hoping that someone can help with a problem of a chuck that is stuck on my lathe spindle. I am on the finishing jobs of my rebuilt Harrison L5 and had screwed the chuck on with very light hand pressure only after cleaning both spindle and chuck then applying light oil. I have not even turned anything in the lathe but when I have come to remove the chuck its stuck fast. Proper stuck fast too.
  So far I have tried .
                 large hex bar in the chuck and big spanner on it, tapping the spanner to shock it and jerking spanner with the gear train locked so the spindle can not rotate.
                 The usual realeasing oils etc, left over night and also repeated after heat applied
                 Removing the chuck from the backplate , incerting 3 bolts through backplate holes and levering with 3 feet long 1 inch bar , hitting said bar to shock
                 Heating the backplate up with propane torch and trying to shift while hot , then when cooled again, tapping all around trying to break seal
                 Replacing chuck and chucking large hex bar then trying to loosen with large socket and windy gun. ( only thought of this after the other attempts )

   The force used so far and the hits have gradually reached the point where something is likely to break if any more force used so looking for ideas. It would seem totally impossible that it has become stuck this tight. I know 100% the threads are clean, there is film of light oil and the chuck has not been tightened other than by light hand pressure.  I am assuming the rear face is seated against the spindle shoulder and the 'lock' is between this and the threads, will this be the case ? I think it must be as this chuck has been on and off many times before and I know the register is clean and oiled as are the threads.

Here are some photos of what I am dealing with.
 
 This is a samller bore Harrison spindle of the exact same design showing the thread, register and shoulder, then the chrome cover, note the shoulder sticks out the chrome cover a small amount. The actual one on the lathe is clean and spottless and oiled.


This is the same design backplate that is stuck on my spindle, showing the register and rear face that is butted tight to the shoulder on the spindle.


This is the stuck backplate with the bolts through it , that the large bar was acting against both jerking and hitting with the gear train locked stopping the spindle rotating, I have gone to maximum force with this , it would have shifted a truck wheel nut in my opinion.


This is a shot to show the spindle shoulder just visible coming out the chrome cover, the backplate is mated up to this. I have a parting tool in the tool holder to show roughly what a plan might be ?


The red small tube is pointing  to the spot that I could with a slim parting tool slice into the backplate just shy of where it mates to the spindle shoulder and releave the tension or compression causing the locking.


 So really what do peolle think is causing the thing to be seized, what I think some sort of hydraulic type lock or taper type lock between the backplate mating to the spindle shoulder or could it be the threads ? they are clean and oiled. I would really like to svae tha backplate as a hard job to find them for decent price and do not want to have to make another one, I do not want to damage the lathe in any way.
  All Myself and a friend can come up with is to maybe drill very small holes in the backplate so releasing fluid could be directly introduced into the threaded area ( if that is what the problem will be) Or to make a special parting tool so it could part away the very end section of the backplate nearest to the spindle shoulder yet miss the spindle by a thou or two, I could also make the tool so it could not go in too deep and mark the spindle as I have a smaller spare backplate with the exact same register to measure.

 Any help most appreciated

 Cheers Mick

[Fergus OMore]

Mick,
         It probably needs a shock to remove it. To avoid damage, I would put a  longish piece of wood in the three jaw, and clout it with one solid blow rather than try to lever it off. If all fails, the wood rather than anything else will go.

Regards

Norman

[vtsteam]

Mick, now I know you do fine work, to get a wringing fit like that on a restoration job!

Any urchins wandered into the shop, with super glue?

Wife been smiling to herself lately?

I vote for Fergus' shock treatment, too.....

[lordedmond]

Mick

With the methods you have tried ,and respecting your skills

The only way out IMHO is to turn the thing off to just larger than the register and threads, much safer than shock loading the gear train ect.

Some have had success with clamping the spindle with a stout wooden clamp and using that to hold it fast while you give it some wellie , but it's something I have not tried


Stuart

Btw great restoration

[Fergus OMore]

No 'toffee hammers', at least you want a club hammer. You have to frighten it- not vice versa.

If you are squeamish, jam a wooden wedge to hold the spindle while you 'talk to it'.

I got one of these bastard Myford backplates which had been tapped 60 degree instead of 55 Whitworth- that is what I did.

It's a doddle compared to moving a stuck clutch plate on a tuned Mini Cooper

Norman

[Pete W.]

Hi there, Mick,

Sorry to hear of your problem especially after all your work and with the lathe looking so good! 

Could you make one of those gizmos that grip in the bore at the rear end of the spindle?  With a tapered plug drawn into a tapered bore by a draw-bolt to expand it in the lathe mandrel bore.  Like the mandrel handles some folks use for threading. 

If that could be made to get a firm enough grip on the lathe mandrel, it would avoid using the gears to lock the mandrel and risking the dreaded toothe-ache!

If I remember rightly, you do have another lathe?

[awemawson]

Was the chuck at a different temperature to the spindle when you put them together?

Invert an HSS tool you care little for but is beefy in tool post, run lathe slowly in reverse, take an intermittent heavy cut on something suitable in scrap bin. Have 'chuck board' under chuck for when it unscrews, hover hand / foot or whatever over brake and watch like a hawk

[stig]

Mick,

with the chuck attached can you clamp a section of hex bar in the jaws and then use an air powered impact wrench like they use for car wheel nuts to undo it off the threads?

[tekfab]

Strip it back to the backplate as in your third picture and use heat, don't piss about with a blowlamp  either use oxy/acet  or a tig set up will keep the heat more concentrated and it should spin off no problem.

Mike

[tom osselton]

I would go for the running in reverse using the cutter or the impact first.

[micktoon]

Hi lads thanks for the in put so far .
 Stig, I have tried the windy impact gun on the about 30mm hex bar no luck, it is good windy gun and will shift most stuuborn bolts on Landrover etc.

 Mike , I have ran out of oxygen , I dont want to damage the backplate by tig ing if I can but will if I have to.

 Andrew, both lathe and chuck have been in the same place forever so will have been same temp, the inverted tool is good idea and I can probably try but to be honest
 I have had real force applied to the backplate , I would say lots more than a cutting tool would produce ?

 Norman,  when I say I have give it some welly I mean really I have large copper hammer full belt onto inch bar wedged through M12 bolts through backplate with spindle locked via gears and the 3 feet long bar also jerked down with full weight until its flexing and it was a hardened steel bar. if the lathe was not frightened it must be hard as nails lol

  Stuart, the wood clamp idea had crossed my mind its on the possible list but hoping not to have to make something complicated.

 Pete, I think your idea gets the vote so far , mainly in part , what happens when this happens again, also as you say cutting all gears etc out the chain..........the last thing I wanted was another bloody project to make something to do a job......... but I should have known lol

 Thanks again for the ideas so far................. so does anyone think they know exactly how it has become so stuck from putting on by hand, what is stuck to what ??

 Cheers Mick
 

[BaronJ]

Strip it back to the backplate as in your third picture and use heat, don't piss about with a blowlamp  either use oxy/acet  or a tig set up will keep the heat more concentrated and it should spin off no problem.

Mike

I agree this is the way I would go.  Lock the gears and use a wooden wedge as well !  Use a long bar as a lever and apply some rapid intense heat around the backplate but keep away from the spindle bore.  You want to expand the backplate not the spindle.  Apply a high pressure to the bar whilst you heat it up.

I would suspect that the backplate was probably hot when it was screwed on.

HTH.

[PekkaNF]

Bummer....Can't really use too much impact because fear of brineling the bearings or breaking gears. Propably impact wrench with limited pressure would be least detrimental. Can't use too heat, because of the seals, bearings, hardened parts etc.

To me intermitent cut + some sort of bar inside the chuck to prevent the chuck (or back blate) bouncing around sounds worth trying, maybe a little heat from hot air gun outside the back plate and then cold spray inside the spindle .... it's not much, but combined effect might be enough. Here we probably want maximum diameter and plenty of extension from the chuck to make it walk out of the lock. You have penetrating oil, you need a little movement there.

I have had some joints I was pretty sure will not come out without a angle grinder but few days of penetrating oil and heat/cold cycle got them eventually undone. I know this is not rust, but situation is pretty much the same.

I'm really really reluctant to hit anything on lathe spindle if it has AC-bearings or such.

Pekka

[Bigbadbugga]

Id say awemason might have touched on the answer, if the chuck and register were hot and cold compared to one another then a snug fit could easily have become an interference fit once they equalise.

[BillTodd]

Do not engage the gears - hold the spindle in neutral with  a split bar gripper thing inserted into the rearof the spindle.

protect the bed  with wood so nothing can hit it.

bolt a short bar to the back plate (get every thin a stiff as possible) and hit it hard n fast with a good size hammer .

Or

just machine it off - it would be a real shame to damage that beautiful restoration.

[vtsteam]

As to causes, I was half joking about wringing, but maybe?

http://en.wikipedia.org/wiki/Wringing_%28gauge_blocks%29#Wringing

The other thing I was thinking of was an unnoticed cracked thread working loose and jamming across in a way that the more pressure applied the greater the jamming force.

In tractor restoration work one thing sometimes written about is trying to turn in the tightening direction first to break loose a really bad lock.

[stirling lad]

sitting quietly reading this with interest and finally V T said what i'd been thinking...tightening first has always worked for me but then ive never had a problem this size before.. I would'nt imagine it could get any tighter so i'd give it a go,,1 whack to tighten followed by  a bigger one to loosen,,but use the hand turning shaft in the back end of the spindle..to brace against....
as for causes,?? no idea,, but if theres a tight vacuum in there would a very small hole towards the shoulder or even the thread help break the seal??

...Mike..

[Manxmodder]

Steve, the wringing theory is worthy of considering but I honestly don't believe that there is anywhere  near sufficient cling to resist the type of force Mick has been using to try and remove the threaded chuck plate.
All the twisting force and shock that Mick has applied would have easily broken the attraction/bond of any wringing that may be potentially caused by oil on the 2 faces.
 The easiest way to separate 2 wrung surfaces is to apply sideways shearing force to slide them apart which is exactly what Mick is doing by trying to unthread the chuck plate.

I do wonder if the soft iron thread inside the backplate has torn or galled a bit when it was screwed on,or if the thread in the backplate has run up against the shoulder of the spindle register and caused the lead thread to deform slightly.

The spindle nose/thread and backplates on my Harrison are the same as Mick's and to remove a chuck I use a 2 foot long piece of 1" square box section gripped across the jaws and with the lathe in a low speed gear for resistance normally only requires a good thump with the palm of my hand to break free.

There have been occasions after some heavy turning has tightened things more than normal the I have had to resort to using the copper mallet to strike the end of the piece of box section and a couple of very firm blows have been required to get things moving.

I wouldn't bother with air driven impact guns because the mass of the chuck or even the backplate is such that the relatively small inertia force from the gun is  absorbed by the mass.

Mick, by all means try some heat and a couple of thumps with the mallet again,but beware of transferring too much heat into the head bearings.

This may very well be a situation where some very careful machining work is the only viable option to remove the backplate.

Another option I would seriously consider is splitting the backplate thread along its length.This would require at least one groove or slit be cut in the backplate  parallel to the spindle and down as near to the crest of the spindle thread as possible,then a wedge or chisel used to open the slit and produce a break along the cut line axis.

Mick, beware that because neither the spindle or backplate are hardened if the thread has galled then just unscrewing it forcibly could tear and do a lot of damage to the spindle thread,that's why splitting it may be the best option. If you need any comparative measurements from my spindle for reference just ask......OZ.
Edit to add: your cutting the register boss with a parting tool idea also has merit,but just make sure no cast iron swarf or dust enters the small clearance gap between the chrome bearing cover and the spindle.

[stirling lad]

  Off topic for a second, but ..
Mick your lathe restoration is looking magnificent..I love it... I really feel for you, getting a monster snag like this especially at this stage when your so close to completion...
 

best of luck...

...Mike..

[RussellT]

I'm not sure I can offer any useful advice but I can offer sympathy.

If the chuck wasn't fully screwed home and the lathe started it might have seated with a jerk which can get things fairly tight.

It seems to me that the main difficulty is applying enough force without damaging the rest of the lathe - in that case pulling the spindle out might be the best option - you could make suitable clamps to hold it without damage.

The other option is to sacrifice the back plate - which will cover your beautiful restoration with loads of nasty cast iron dust.

Good luck.

Russell

[Fergus OMore]

I am merely guessing but the bull wheel etc will be or should be held on the spindle with a long key.
This is the bit that will take the brunt of the clout. The rest of the gears etc can be locked with wooden vee wedges forced between the gears and the headstock casting. ( This is how it goes on a Myford anyway)
If you can put a long steel rod neatly onto the 3 backplate, you can clout it loose.

OK, you can bugger the keyway mentioned and you might need a very long scaffolding pole but it should 'give'.

I recall using a scaffolding pole to release what should have been on at 140 lbs.feet and literally jumping on it with  all of 11 stone massively constructed masculinity( well!) but it did give.
Brute force and applied ignorance!

You know I was thinking of the screaming of tortured car body metal when pulled with a 'warwick' into alignment after a crash.   

Best of luck

Norman

[awemawson]

Mick, I do have a 1" drive air operated impact driver you could use if you have a big enough air source - I run it off a road compressor. Big hex in chuck and suitable socket should eventually shift it. (Got it for various big bolts on farm machinery)

I still think that a heavy reverse interupted cut would do it

[BillTodd]

I still think that a heavy reverse interupted cut would do it

yes, but think what would happen when it does ;-)

[Manxmodder]

Fergus OMore said:I am merely guessing but the bull wheel etc will be or should be held on the spindle with a long key.This is the bit that will take the brunt of the clout

Fergus, the spindle and sliding bull wheel are located on very beefy splines rather than a keyway,there is little likelihood  of damaging either through high torque or shock......OZ.

[awemawson]

I still think that a heavy reverse interupted cut would do it

yes, but think what would happen when it does ;-)

Nowt if the chuck is holding a long bar that goes up it's spout - but as I said earlier, use a chuck board over the ways, slow speed, and hand / foot hovering over brake.

Might start with washing up bowl under chuck and pour a few kettles of boiling water over the back plate before starting (not forgetting to remove the bowl  before running )