Best grease for taper roller lathe spindle?

I am about to regrease my Stepperhead lathe spindle just to check the bearings etc. At present the bearings are lubricated with moly grease, but I just wonder if there is a better choice.

Alan

Why did you use moly grease in the first place?

IIRC moly is an EP additive, for use when there is considerable pressure and the lube film may break down.

I would think a quality lithium grease would be fine.

Dave

+1 for Lithium or Calcium grease.

Molybdenum grease may be OK where there is sliding motion, but it is not ideal for rolling motion. In the very worst case, it might even lubricate so well that the rollers do get enough grip to roll!

Howard

Would that matter? Lower friction surely?

Use a lithium high melting point available from any car spares shop. The moly grease is not recommended for rolling element bearings as the molydenum can make the surface brittle chemically, as already mentioned it is best for plain bearings. The original grease might have had graphite in it making it black colour. Only fill the space 50% maximum to allow the grease to be displaced from the bearings as they move.

Edited By old mart on 03/11/2021 19:06:08

I like Teflon grease.

Neil

Teflon is a solid.

Tim

Colloidal Teflon suspension, I think. I have Nulon grease too.

I wouldn’t use moly grease with roller bearings, it can cause total failure, ask me how I know. Dave W

Kluber. We always used NBU15 in high speed spindles but there are many more options now.

You don't need anything more than bog standard Lithium soap grease. High melting point grease is wasted unless your lathe bearings approach boiling point or beyond. Only fill the cone with grease, packed into the cage and rollers, and no more.

My lathe manual recommends a grease type with many letters, dashes etc. I queried this with Castrol, and was told that their standard lithium grease, type LM, was a suitable equivalent.

Peter G. Shaw

I thank you all for your suggestions and have decided to use Silicon grease with Teflon. I seems to be a bit quieter when running so all is good.

Thank you

Alan

Seems an odd choice for a tapered roller bearing.

Seems an odd choice for a tapered roller bearing.

+1

Always regarded silicone greases to be mainly a rubber / plastics lubricant. Perusing some lubricant & bearings manufacturer information suggests that it can be used for rolling element bearings under specific conditions (i.e very low operating temps for lightly loaded bearings), but it does not appear to be a general recommendation. One bearing manufactuer mentions derating the bearing load ratings to 1/3 of normal if using silicone grease & grease manufacturers mention "low speed, low loading".

Really can't see why you would want to use this product in this application - just use a plain lithium bearing grease with no additives as recommended by the bearing manufacturers. Given that TRBs "pump" lubricant from one end to the other, making provision for easy re-greasing would be advantageous.

Nigel B.

Unlike sliding bearings, tapered roller bearings don't actually need much lubrication. The rollers roll, and the only area that 'rubs' is the end of the roller and its mating cone face. When I left the bearing industry and went into research it was becoming common for machine tool manufactures (and we had plenty in the 60's) to use oil mist lubrication which has many advantages.

Maybe the motor industry is to blame for all these additives which arguably enhance performance. Even in engines, the quantity of oil actually used for lubrication could be significantly reduced if it wasn't necessary for it's cooling action.

Bearing manufacturers have been recommending ordinary Lithium soap based grease for decades, and they do very deep research before recommending anything. Why ignore it and waste your money on products designed for different applications?

It's your machine and your choice at the end of the day.

Silicon grease got a bad press from the airgunners who found it promoted, rather than prevented, galling. Probably fine for a rolling contact but you might want to be careful what you do with the rest of the pot.

My M300 uses extremely expensive Gamet Super Precision Taper Roller bearings with ISO32 Hydraulic Oil with the headstock gearing "throwing" the oil for a continuous feed. If it was lathe with no oil feed system I would use Lithium Grease only. Greased bearing run at lower speeds.

All these silicone and teflon based greases - not good if you ever decide to do any painting within 20 miles of the workshop !! Just a smidgen of grease on your hand and paint will not stick to your project. I used some silicone spray outside the workshop as a mold release agent for some epoxy casting. - I wish I hadn't !

Bob

Thank you all for you recents comments on silicon grease with teflon. I bow to your better knowledge and have ordered some lithium grease which will be used. Luckily it is quite easy to remove and replace the spindle.

Alan