Thread: Stuck chuck ....

How did Holbrook intend for the spindle to be locked in order to remove the chuck/backplate?

Phil

Originally Posted by philbur

How did Holbrook intend for the spindle to be locked in order to remove the chuck/backplate?

Phil

Hello

It is not a problem normally when the chuck is being taken off regularly and the spindle register is oiled a bit . In this case , the chuck has been on the spindle since Jack Kennedy was the US President and people in Australia were paid in Pounds and Shillings .

I have made up a tapered plug from aluminium ( it is definitely a .025" per inch taper ) , as the ally is softer than the spindle it will hopefully not damage the taper in the spindle if it slips . I tapped the end of the plug 12mm , I will buy a length of threaded 12mm rod and use it as a draw bar . For such a massive lathe the spindle only has a 1 1/4" bore .

Originally Posted by morrisman

Hello

It is not a problem normally when the chuck is being taken off regularly and the spindle register is oiled a bit . In this case , the chuck has been on the spindle since Jack Kennedy was the US President and people in Australia were paid in Pounds and Shillings .

I have made up a tapered plug from aluminium ( it is definitely a .025" per inch taper ) , as the ally is softer than the spindle it will hopefully not damage the taper in the spindle if it slips . I tapped the end of the plug 12mm , I will buy a length of threaded 12mm rod and use it as a draw bar . For such a massive lathe the spindle only has a 1 1/4" bore .

That doesn't answer the question?

Phil

Originally Posted by philbur

That doesn't answer the question

As much as I like you like a brother for having the right name. Answer is at post # 1.

Holbrook used a double register on the spindle nose , a 2 1/4" BSF thread 3/4" long is between the two registers

Break that free and you're home. Any way you look at it, it's a screwed spindle nose.

Phil,

Originally Posted by Machtool

As much as I like you like a brother for having the right name. Answer is at post # 1.

Break that free and you're home. Any way you look at it, it's a screwed spindle nose.

Phil,

Hi Phil,

I’m not sure of the relevance of your answers to my question?

Threaded spindles were very popular in days gone by, however chucks get stuck on these threads for a whole varieties of reasons. People who don’t know any better put the lathe in low (back) gear and then heave on the chuck and only succeed in breaking a couple of teeth on the bull gear. Manufacturers like Holbrook would have been well aware of this risk so would have provided a means of locking the spindle to enable the chuck to be safely unscrewed without the risk of overstressing the gear teeth.
So my question remains, has the OP looked for how the spindle is locked for chuck removal.

Phil

Originally Posted by philbur

People who don’t know any better put the lathe in low (back) gear and then heave on the chuck and only succeed in breaking a couple of teeth.

Originally Posted by morrisman

I did try this, I selected the lowest gear 15 rpm and placed a 1 " gal pipe in the 3 jaw chuck and gave the end of the pipe a few blows , all that did was bend the pipe .

Are you Bloke's singing from the same hymn book?

Phil, you're 3 days late, how the does he get that chuck off????

On my Myford lathe there is a pin that when pushed in locks the spindle ! Its at the tail end of the spindle where the gear train is and it pushes into a hole drilled into the large belt pulley.

Originally Posted by shedhappens

Why not bolt another plate to it with a big nut welded to the centre, with the g/box in a neutral position zapp it with an impact gun, 3/4" or 1" square drive if you can, you might loosen it without even holding the shaft.shed

Mike that idea has worked for me before ,but first I would heat the backing plate as quickly as you can with a large tip oxy acet or oxy lpg .A dull red then let it cool on its own, idea get the plate as hot but not spindle. Then try your rattle gun or even a larger piece of pipe over a socket bar and a large club small sledge aim is to expand plate not the spindle. Old threaded spindle noses don't need much to lock up solid.Here have a large piece hex about 2in from memory and a square milled 1 end and the other plain removes your 4 jaw and 3 jaw with socket rattle gun or FBS.With unknown old clunkers my suspicions would have been a chuck only machine most its life the taper may been bored out so larger dia work pieces go further in. Being british manf suspect h/s be morse no 4 or 5 and tail stock no 4.Your machine looks far better than the pics of the restored one looks like it used up every bit of its commercially viable life.By the way is not an ex Kreisel machine Warragul they used to have some rippers through the glass window at front. Hope another bit helps said the monkey raising the water level in the river. Cheers John.

Originally Posted by Machtool

Are you Bloke's singing from the same hymn book?

Phil, you're 3 days late, how the does he get that chuck off????

I thought the chuck was already off and he was trying to work out how to lock the spindle in order to screw the back plate off. My point was that manufacturers of quality lathes with threaded spindles usually providea means of locking the spindle specifically for the purpose of unscrewing the chuck/back-plate. What did I miss?

Phil

Originally Posted by philbur

I thought the chuck was already off and he was trying to work out how to lock the spindle in order to screw the back plate off. My point was that manufacturers of quality lathes with threaded spindles usually providea means of locking the spindle specifically for the purpose on unscrewing the chuck/back-plate. What did I miss?Phil

Phil not that many did that some had their own set ups ie Colchester. Nothing would be more scary than a 100kg chuck or any sized chuck for that matter unscrewing and hopping off the bed and scooting across the floor making mayhem. Lots and lots old machine shops had earth floors and duck boarded for some minor ''creature comfort' '.An old John Lang lathe we had for years had a screwed in pin we made to hold the chuck backing plate if used in reverse that was often used to wind back the saddle. A real man killer to work it made the ''gravy'' run even on a freezing cold day. Tail stock was so heavy that you had to drive the saddle down lassoo the tail stock with its own chain and bring it up either winding handle or driving it up under power. The motor had such a high inertia start that it would or could unscrew the chuck,lather we modified it with a clutch between motor and gearbox.If you wanted to cut a thou .001 it would do it. Langs made some of the finest machines.

Originally Posted by j.ashburn

Phil not that many did that some had their own set ups ie Colchester. Nothing would be more scary than a 100kg chuck or any sized chuck for that matter unscrewing and hopping off the bed and scooting across the floor making mayhem.

Hi, Iwas referring to a mechanism to lock the spindle in order to allow the chuck tobe unscrewed for the purpose of removal, not a mechanism for preventing thechuck from accidentally unscrewing when in use.

Phil

Originally Posted by morrisman

HelloIt is not a problem normally when the chuck is being taken off regularly and the spindle register is oiled a bit . In this case , the chuck has been on the spindle since Jack Kennedy was the US President and people in Australia were paid in Pounds and Shillings .I have made up a tapered plug from aluminium ( it is definitely a .025" per inch taper ) , as the ally is softer than the spindle it will hopefully not damage the taper in the spindle if it slips . I tapped the end of the plug 12mm , I will buy a length of threaded 12mm rod and use it as a draw bar . For such a massive lathe the spindle only has a 1 1/4" bore .

Mike my Dr Zeus overall pocket data says no3MT = .6023 per ft . No4 is .6233. .025 X2= 0.600 a little wear or galling and not far off John.0.025'' per in you say 0.025 X12=0.600 hope it helps J A.

South Bend has no provision for locking the spindle to remove their threaded on chucks.

Originally Posted by j.ashburn

Mike my Dr Zeus overall pocket data says no3MT = .6023 per ft . No4 is .6233. .025 X2= 0.600 a little wear or galling and not far off John.0.025'' per in you say 0.025 X12=0.600 hope it helps J A.

Thanks for the ideas John .

Phil from Uk . Reading through the Hobrook manuals , there is not any reference to any lock for the spindle . Apparently most if not all of the lathe manufacturers of yesteryear , did not provide any method for locking the spindle , I wish they had . My Hendey has no spindle lock either .

Back to the problem, I have made the lever that bolts to the back plate , I used a piece of flat plate with 3 holes drilled in it , same hole pattern as the back plate . I have welded a 2 metre long 40mm square section tube to the plate . My main problem might be the ally taper plug in the spindle bore , I hope it does not slip , I am tempted to use loctite on it to hold it .

Anyway I will give it a try tomorrow when I have the draw bar here . I don't have a oxy heat source only a BBQ gas torch which does not have enough heat output but its better than nothing .

I think the odd taper that Holbrook used in the spindle is actually for a adapter that accepts a MT 3 or 4 centre Mike