Plain Bearing Headstock Oil Cup Design

[MrStretch]

Hello all,
I am curious about the differences between the headstock oil cups on my 2 Stark #4 plain turning lathes. The newer one from the 1920's which I've owned and used for years has very close fitting lids ( make a "pop" when removed ) and an internal stand pipe


I have always filled up the standpipes & cups with oil whenever I start using it which is relatively infrequently. The oil is definitely being drawn from the cup into and out of the bearings (aka leaking all the time ), so I never really gave it much thought.

My new to me and older Stark #4 has the same kind of bearings but the oil cups have heavy loose fitting lids and no standpipes


I think that I need to maybe to plug the stem with a small bit of felt or something so the oil drips thru or perhaps it's fine as it is because you can't over-oil it?

PS - it's cleaner than it looks in the pics. The cap was originally plated.

 

[L Vanice]

I think both types of oil cups should have the narrow passage filled with natural color wool yarn. The one with the tube should have the yarn passed over the top of the tube and extended down to the bottom of the reservoir. I never had a Stark, but my old Hardinge Cataract machines made extensive use of wool yarn and wool felt in the spindle oiling system. The yarn can prevent dirt from getting into the oil passages and can also act as a capillary to make oil climb up out of a reservoir..

This page from Tony has several cross section drawings of plain bearing Cataract headstocks showing the yarn-filled oil reservoirs below the bearings that feed felt pads that contact the bottom of the spindle. The oil cups are on the rear and feed oil into a groove in the casting that connects with the tops of the reservoirs. It was a very good system.

Cataract Lathes

Cataract Lathes - high-precision American-made for toolroom and experimental shop work

www.lathes.co.uk

Decades ago, I found a craft store that had packages of various color wool yarn cut into short lengths specifically for making hooked rugs. A package like that of natural color will last a lifetime of rebuilding lathes. A millwright/machinery repairman where I worked tipped me off to only use wool in oiling systems, never a synthetic yarn or felt.

Larry

 

[jim rozen]

I've been to this rodeo - Potter lathe with the 'no standpipe' oil cups. Front bearing kept oil in it, while running, for a long time. The rear bearing pumped the oil cup dry in minutes. My approach was to install modern wick-feed oiler with the standpipe. Originals were 00 size Lunkenheimer.

 

[MrStretch]

Thanks Jim. I will be reassembling the spindle today and I think that I will try the cups as they are and see what happens. The spindles/bearings on these lathes are constructed exactly like a watchmakers lathe, so it's possible that the bearings themselves might provide enough back pressure to keep the cups from draining too fast. If that doesn't work I'll try packing the stems with a tight fitting wick or felt cord. It would need to be tight fitting since there is no standpipe.
I may be wrong, but I don't think it's possible to over-oil a gravity fed total loss oil system?

 

[jim rozen]

in my case over-oil meant the rear (and only the rear) oil cup would empty out in a minute while running. Not running, it would last a week. The lunkenheimer plain oil cups were replaced with gitts wick-feed ones.

 

[MrStretch]

So far, so good. The cups are holding oil with the lathe not running. If it works without any alteration, it's just more evidence of the outstanding quality of Stark lathes, including the early ones. I'd like to keep it as original as possible.

 

[MrStretch]

Well, turns out the cups leak down very quickly when the lathe is running.
After looking at the prices of oil cups from McMaster, I decided to simply add standpipes to the existing cups by broaching out the stems with a tapered cutting broach and then tapping in pieces of tube that I tapered with a file and pin vise. Looks good. I am using bits of undyed cord for wicks. Might replace them with pipe cleaners someday.

 

[jim rozen]

Deja vu all over again... Oddly only one of the oil cups on my lathe pumped dry fast like that. You'll do fine with the new setup. They'll probably empty over time just by capillary action, but while running just the occasional top-up. I did buy mine from mcmaster and yes, they were dear.

 

[Conrad Hoffman]

The top cup on my surface grinder uses a wick to pull oil up and over a standpipe. It's always amazed me that on a hot day when the oil is thin, it will empty a good ounce or so of oil in under a day.

 

[MrStretch]

I think there must be good logical reasons for the 2 different designs, but I'm not smart enough to figure them out. My biggest concern is under oiling the headstock so I'm hoping the steady drip from the standpipe/wick will be good enough. I can still fill it up completely before use so maybe it's OK?
As a conservator, I hate altering original parts but the change is only visible when the caps are removed so I guess I'll get over it.

 

[aboole71]

If it works without any alteration, it's just more evidence of the outstanding quality of Stark lathes