1920s lathe spindle removal

[Aston ManningParticipant @astonmanning46959]

Goodmorning, I have an old lathe and can’t remove the bull gear from the spindle

I think it’s the bull gear is threaded on the spindle.

I want to know the best possible way to remove it.

I can put a pair of grips on the spindle but I don’t want to bend or create burs I’ve tried to remove it this way already but it, it’s on very tight

[Aston ManningParticipant @astonmanning46959]

Old lathe

[vic neweyParticipant @vicnewey60017]

What make is it? the grooved belt pulley is rather unusual

[Ady1Participant @ady1]

The bull gear tends to be keyed directly to the spindle because it is the last link in the backgear

So tapping the spindle forwards usually releases it from the spindle

The pulley and small backgear on the spindle are usually independent from the spindle

Don't recognise your unit, it looks pretty fancy, is that an integrated tumble reverse at the back?

edit: Whatever it is it may also be keyed onto the spindle

Edited By Ady1 on 25/07/2023 10:25:32

[Ady1Participant @ady1]

If it was threaded on then it might unscrew under pressure in reverse which would be disasterous so there's a 99% chance the bullgear is not threaded on

[Bill Davies 2Participant @billdavies2]

Looks a bit like a Britannia lathe, except that the backgears at the screwcutting gear end look unusual to me. I would expect nuts at that end of the spindle, which control the tightness of the bearings, and which, if removed, may allow the spindle to come out through the front spindle, as Ady1 suggests.

Bill

[Aston ManningParticipant @astonmanning46959]

Thanks all, that makes sense. it isn’t threaded there’s a gap just big enough to see where the threads end

the make is LM, I haven’t seen anything that make like it on the internet

I can’t tap tap it out because of the two bearing adjusting nuts

I’ve tried hitting the gear with a hammer and wooden block to try to loosen it but there is no movement at all

The spindle has most likely been out before because the pulleys are grooved

there’s not a big enough gap to pry it

[Aston ManningParticipant @astonmanning46959]

[Ady1Participant @ady1]

There's a Drummond headstock here

[Ian PParticipant @ianp]

I think it highly unlikely that the bull gear has an internal thread onto the spindle, most likely it is keyed especially if there is no grubscrew or hole for one.

From the pictures you have shown its not really possible for anyone to see enough detail of how the spindle/headstock is arranged. What is the bearing at the rear of the spindle?

Is the pulley itself free to rotate when the backgear is disengaged? (I presume it on an eccentric spindle)

What sort of bearings supports the main spindle, Plain or ballrace?

There appears to be a painted over screw on a cover at the back of the spindle, removing that cover might show something.

Ian P

[Ady1Participant @ady1]

The first bits off will have to be the bits at each end of the spindle on the outside of the housing

If you can't do that then the rest of it is academic

[Ian PParticipant @ianp]

Posted by Ady1 on 25/07/2023 13:58:34:

The first bits off will have to be the bits at each end of the spindle on the outside of the housing

If you can't do that then the rest of it is academic

+1

[old martParticipant @oldmart]

The spindle will almost certainly come out to the right (chuck end). Look at the left end for threaded rings which control the end float and also hold the spindle in.

[Aston ManningParticipant @astonmanning46959]

There is a hole for a grub screw

I don’t know if it has been broken off in the past and some of the screw has been left in the hole?
Is it wise to drill it out and retap it once off just in case or will I risk damaging anything? It’s the only thing I can think of why it’s not coming off

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Aston, shouldn't do any harm drilling it out, try one that fits in the hole first, but you need to get some idea as to how deep to drill it, as it's probably in a dimple, and you may need a solid carbide or cobalt drill bit if it's a hardened grub screw.

Regards Nick.

[Ian PParticipant @ianp]

Posted by Nicholas Farr on 26/07/2023 11:20:53:

Hi Aston, shouldn't do any harm drilling it out, try one that fits in the hole first, but you need to get some idea as to how deep to drill it, as it's probably in a dimple, and you may need a solid carbide or cobalt drill bit if it's a hardened grub screw.

Regards Nick.

The hole shown in the picture appears to be in the headstock casting (bearing housing) so more likely to be a lubrication hole. I cannot imagine it would have a grubscrew in it.

Almost 100% the spindle should be removed from the chuck end.

Is there any movement endfloat at all in the spindle?

What is under the cover at the right hand end of the spindle?

Does the pulley revolve freely relative to the spindle?

A picture showing more of the headstock arrangement (not a close up) might help.

Ian P

 

Just noticed there are two hols in the last picture, one being in the bull wheel. More likely a pin than a grubscrew if its in the bull wheel as it has to transmit a lot of torque.

Edited By Ian P on 26/07/2023 11:33:10

[Aston ManningParticipant @astonmanning46959]

I’ve decided not to drill it, I just remembered that this screw used to be in it

[Ady1Participant @ady1]

It looks like it could be a rather good precision lathe

[Aston ManningParticipant @astonmanning46959]

[Aston ManningParticipant @astonmanning46959]

[Aston ManningParticipant @astonmanning46959]

I have no idea what the screw is for🤷‍♂️

[Ady1Participant @ady1]

I suppose I should ask the unasked question

Why do you want to remove the bull gear from the spindle?

[Ian PParticipant @ianp]

Posted by Aston Manning on 26/07/2023 13:10:06:

I have no idea what the screw is for🤷‍♂️

Which screw are you referring to?

Ian P

[Aston ManningParticipant @astonmanning46959]

I need to fit a new belt. It’s a continuous belt so I need to remove the spindle. I’ve loosened everything on the spindle apart from the bull wheel which I have no idea how to remove

i was referring to the screw in the picture which screws on to the bull gear

[Howard LewisParticipant @howardlewis46836]

Silly question.

What happens if you take C spanners to the nuts and unscrew them?

Do they control the endfloat, acting on the adjacent bearing?

If so, unscrewing them ought to let the spindle move through the bearing and out of the Bull Wheel and three sheave pulley, to allow the new belt to be fitted.

Then just a matter of reassembly and restting bthe end float of the spindle.

Howard

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