servicing my new lathe?

[PeteFr2]

Hi everyone,

Just taken delivery of a G Boley Geneva 8mm watch lathe with a comprehensive set of tools and a reversible motor (multifix). I am familiar with lathes, my background is in engineering but obviously larger gap bed lathes.

Before I start using it I'd like to service it, in particular the headstock bearings. There seems to be no play in the headstock so I assume the bearings will be ok, however I'd still like to clean them out and lubricate them before I use the lathe. I've never done this so I'm not sure how to strip it or what lubricant to use, are there any pitfalls I should consider?

Any help or advice much appreciated.

Thanks,  Pete

[nickelsilver]

A pic or two would help, but generally there is a nut at the rear of the spindle that needs to come off, these can be split and hold on by friction, or have a set screw. This is the adjusting nut. The pulley will be held by at least one screw, sometimes 2 or more (usually 1). The rear bearing is keyed and is a sliding fit, very very close, on the spindle. With everything loose, use a brass drift and knock the spindle out the front.

For oil I use ISO 22 but any light oil is OK. It's a constant-loss design, you need to oil it every time you use it. Your white shirts will have a nice oil stripe in line with the front bearing...

[PeteFr2]

Thank you. 

I'll have a look based on the info you've given me and also try and post a photo later.

[Tmuir]

Two books also work getting is Donald de Carles book Watchmakers and Model Engineers lathe which is easy to come by and not that expensive.

Then there is Archie B Perkins book 'The Modern Watchamkers Lathe and How to Use it'

Archie's book is expensive and not so easy to get but is very much worth it and has a whole chapter just on stripping down cleaning and oiling the headstock. It even goes into regrinding the cone bearings which I think is a step beyond what most of us can do.

[PeteFr2]

Thanks. I actually ordered Perkins' book this morning so it's good to know that it's worth getting.

I'm sorting out all the components at the moment - I'm sure I'll be back with more questions if that's ok.

[PeteFr2]

Thanks to everyone who replied re my uncertainty in servicing the headstock bearings on my Boley lathe. I have now successfully finished the service and will (attempt to) post a photo below of the disassembled components and description of the process, hopefully to help anyone else who is considering doing this for the first time as I was.

Process was as follows:

Remove the 2 dust caps (one either end), these are simple split ring unthreaded knurled dust caps. They have a semi-circular cut out in the inner face which by turning them on the sleeve reveals an oil hole drilled in the stub of the headstock to lubricate the bearings. I found it easier to loosen them by pushing a blade in the split.

Next remove the back nut, again a split knurled nut which releases easier if expanded slightly with a blade in the split and unscrewed anticlockwise (right hand thread).

Next I preferred to remove the grub screw in the pulley. Then the spindle can be tapped out from the rear using some form of protection on the end, I used a piece of hardwood. This wasn't difficult. The front inner race stayed on the spindle, the rear inner race was removed as the spindle was persuaded forwards, don't forget to support the pulley. My model has plain taper bearings. After a thorough cleaning and inspection I lubricated the inner races with a few drops of quality clock oil and reassembled. I then adjusted the end float with the back nut until I estimated approx. 0.01mm end float as I have always understood that taper bearings require some end float to allow for expansion when running. After checking there seems to be no perceivable side shake or run out and the spindle is now a pleasure to turn. 

I hope this helps someone and I would welcome any comments from the more experienced on my amount of end float.

Can I ask someone to study the photos and tell me why my German Boley has an English component fitted in the pedestal, did Boley source certain components from other manufacturers or have I bought a 'bitsa' lathe? It is the only component with the kit which is not Boley.

Thanks, Pete

[PeteFr2]

[measuretwice]

Base is from a Henri Picard lathe.   I just saw a post on NAWCC that identifies the P in a spade as being Henri Picard and remembered this thread.  Apparently the maker was originally Swiss but moved to England.   They are still around but I don't think make lathes any longer

[rodabod]

I wouldn't call it a "bitsa". The lathe mount doesn't really matter as long as it works. Main issue is having the headstock, bed and tailstock in alignment.

[david]

PeteFr2,

When I reassemble the spindle assembly I smack the nose cone with a wooden 2x4 to help seat the spindle into the cone bearings. To adjust it I tighten the nut on the back while slowly rotating the spindle by hand until it feels tight. Then I back off the nut about 1/4 of a turn. This is something that has to be done by feel.  The spindle needs a microscopic gap to allow it to ride on the lubricating oil   The  lubricating oil should be the actual bearing. The ideal gap would be the distance of one molecule of oil but the practical distance will have to be slightly larger. I then run the lathe for a short period and check for any heat buildup in the headstock. If it becomes warm it is too tight and the nut needs to be slightly backed off. The last thing I do is check the inside cone runout with a 1/10,000 inch dial indicator. The runout should be around 2/10,000 of an inch. Do not try to go past that or you can damage the lathe. This issue with cone bearings was a limiting factor in precision for hundreds of years. Around the WW2 era Derbyshire finally improved on it when they began producing lathes with ultra precision ball bearings. They were able to achieve a spindle runout of around 50/1,000,000 of an inch. Both Derbyshire and Levin lathes have  reduced spindle runout as far as ball bearing spindles will allow. The only way to surpass this is with air bearings or hydrostatic bearings.

david

[PeteFr2]

Thanks everyone. Sorry haven't replied sooner I haven't checked the forum recently as I got side tracked reorganising and sorting out my workshop area, just about to make a couple of new work benches to replace the old kitchen table I was using and then I can set the lathe up.