Thread: Headstock Spindle Advice Please

Originally Posted by nearnexus

It's interesting reading some aspects of this thread.

The assumption that a lipped seal will cause enough friction to heat up a spindle is apparently a big worry, but it's nothing compared to heat build up from pre-loaded roller bearings, which is apparently OK.

I'm just a little surprised that a tiny lip edge on a seal could be such a major heat source - I find that hard to believe, as it would just burn itself away in a short time without oil and if lubricated spin harmlessly with oil.

I agree that an "O" ring is not generally used for a high speed spindle.

Although I generally dislike quotes from Wikipedia as it's less than accurate on a lot of stuff, I think it touches on the main points in this case:

Labyrinth seal - Wikipedia, the free encyclopedia

Labyrinth seals (or oil slingers) have been used for a long time as an alternative to a felt or neoprene seal in a variety of mechanical devices, but I have serious reservations that it's a heat related choice.

In regard to preloading roller bearings, on my lathe the tension is correct if it takes the chuck and spindle 1.5 turns to stop when spun by hand, with the change gears and drive system disconnected.

Cheers

Rob

I agree about the seals Rob, I couldn't see them generating any large amount of heat.

Dave

I'm thinking that the reason for not using a lipped seal on the lathe spindle would be more to do with the fact that they leak after a while, and they also wear a groove in the shaft, the labyrinth seal don't leak and don't wear a groove in the shaft.

Has anybody here seen a lipped seal on a lathe spindle ?

Originally Posted by nearnexus

In regard to preloading roller bearings, on my lathe the tension is correct if it takes the chuck and spindle 1.5 turns to stop when spun by hand, with the change gears and drive system disconnected.

Cheers

Rob

Ah yes. I'd forgotten about that test. I used that too.

Simon

Originally Posted by shedhappens

Has anybody here seen a lipped seal on a lathe spindle ?

Yes, my chinese lathe has them. They will leak if you overfill the bearings, but I've not noticed excessive heat. Maybe it's designed for that type of seal. I would need a compelling reason to modify a spindle, and an overactive imagination doesn't count as compelling.

Originally Posted by shedhappens

I'm thinking that the reason for not using a lipped seal on the lathe spindle would be more to do with the fact that they leak after a while, and they also wear a groove in the shaft, the labyrinth seal don't leak and don't wear a groove in the shaft.

Yes, I think that's a correct assumption. A labyrinth seal is basically maintenance free and inpervious to metal cuttings and contaminants. Ideal for a lathe situation.

A lip seal however only has to get a small nick in it to render it useless as an oil seal and they do wear out.

I think they are a good idea as a grease seal, and better than the basic dust cover/plate on my lathe.

Cheers

Rob

Also I suspect that the spindle is not hardened (could be wrong) in which case a seal would soon wear a groove and then be useless, leaving no method for retaining the oil.

I'd never seen or heard of a labyrinth seal before I read about it and seen one on my lathe. Brilliant idea. They work well on my machine.

Simon

Originally Posted by simonl

Also I suspect that the spindle is not hardened (could be wrong) in which case a seal would soon wear a groove and then be useless, leaving no method for retaining the oil.

I'd never seen or heard of a labyrinth seal before I read about it and seen one on my lathe. Brilliant idea. They work well on my machine.

Simon

It's a very old design (in quite a few incarnations) and was widely used on engine crankshafts many years ago. Some incorporated a screw type slinger very similar to a thread. eg. I think VW beetles had this on the flywheel end of the crankshaft.

I remember my old man who was in the army during WW2 as a mechanic telling me how lots of old trucks used this design and they soon discovered it's one downside in the field - when fording deep water the screw type slinger became a "sucker" and filled the sump with water - LOL.

Bit of useless trivia.

Cheers

Rob

Originally Posted by nearnexus

It's a very old design (in quite a few incarnations) and was widely used on engine crankshafts many years ago. Some incorporated a screw type slinger very similar to a thread. eg. I think VW beetles had this on the flywheel end of the crankshaft.

I remember my old man who was in the army during WW2 as a mechanic telling me how lots of old trucks used this design and they soon discovered it's one downside in the field - when fording deep water the screw type slinger became a "sucker" and filled the sump with water - LOL.

Bit of useless trivia.

Cheers

Rob

Series 1 Land Rovers used it as well, it works OK on the crank shaft . ( a archimedies screw ? ) The gearbox front seal is similar , you dont 'want to park a early Land Rover pointing downhill, the gearbox oil has a habit of dribbling down onto the clutch resulting in slippage . The Rover factory published a service sheet, explaining how to recalibrate the gear box dip stick e.g., lower the original oil level , in order to alleviate the problem. ............Mike

Originally Posted by morrisman

The Rover factory published a service sheet, explaining how to recalibrate the gear box dip stick e.g., lower the original oil level , in order to alleviate the problem. ............Mike

Ha Ha that's a good one. Never heard that before

Rob

Hi Daryl,
I agree with Peter on the rt/dividing head. I have been meaning to make a base for mine so it can be clamped to the lathe bed infront of the spindle, and on center height. I need to make up some new graduated collars, plus now with the purchase of the tpg sharpening with the aid of an er collet chuck in the rt.
Cheers,
Ew

Hi all,tapered roller bearing pre load will change eventually.with bedding in and running in period is a wise move to check after some use.Opinions vary on pre load ie zero end float plus a nip to allow initial bedding in.In automotive applications you usually never get a chance to do the second check as that vehicle is long gone,The idea is get it right first time.I was trained by an old Italian gent who knew his craft.He showed me how to test by feel as this skill has no text book entries.Also friction of seals has to be taken into account as well so preload is done by feel without seal the with fitment of seal to compare. Eventually is ''old hat'' to set pre load.Many trades people I have encountered over the years get scared of these bearings.it is not rocket science and best way is get in and have a go.Hope this gives you some confidence on your quest.John.

Originally Posted by morrisman

Series 1 Land Rovers used it as well, it works OK on the crank shaft . ( a archimedies screw ? ) The gearbox front seal is similar , you dont 'want to park a early Land Rover pointing downhill, the gearbox oil has a habit of dribbling down onto the clutch resulting in slippage . The Rover factory published a service sheet, explaining how to recalibrate the gear box dip stick e.g., lower the original oil level , in order to alleviate the problem. ............Mike

More trivia army land rovers had a fording plug screwed into bell housing and was fitted to stop bell housing filling with water and then fluid into the gear box.river creek water has silt in it and that going into to gear oil soon took care of the gear box bearings.Those Series 1 rover engine were Rolls Royce design and believe it was one of Henry Royce ideas oil screws. As I do lots of vintage engines here have found that type of screw oil slinger on many engines mostly of British design or origin.British engines usually like to leak oil, as i was told by an old mechanic years ago tells you engine still got oil in it

Thanks John, It's not that I'm really 'fearless' - I have plenty auto experience as an old rally-ist etc. It's just that in this case, the nut at the back of the spindle isn't quite the best fit on it's thread - not what you would expect - having good 'feel' for the rotating bearing will be ok, but I'm unlikely to get 'good feel' while turning the nut. I'm confident that the advice from the above posts plus my own gut-feel, the pre-load will be OK.

On a related (bearings) matter - am I allowed to diverge my own thread a bit??

I have an (3M) ER32 chuck that I plan to install into the (4M) spindle as well. I will make the drawbar such that I can also use it to disengage the M4 (with the ER chuck) - that means giving it a good whack with the brass hammer. I see others have sent posts in other threads expressing concern this 'operation' will have on the bearings - I expect similar damage may also eventuate with changing the chucks in the vert mill.

Perhaps someone has already designed a 'fixed' collar that will allow the drawbar to also push a chuck OUT as well as IN?

As you can all see, I'm becoming addicted to the discussions here

Regards, Daryl

If you keep posting John, how will I EVER get any shed work done?
I like the Rover stories - I have some good ones as well - for another time/thread.
We all know about the Brits & oil leaks starting with the smallest stuff they build/t (Villiers/Bikes/Auto's/Aircraft.)
Its the latter where I have had a lot of exposure _ Canberras, Vampires, Brittanias, - but the best are/were the Bristol Freighters (Bristol Frighteners), they only need a navigator on the outward journey as they could follow the oil slick on the way home and they are also known for famously being able to retain 150,000 rivets in LOOSE Formation

Regards, Daryl