Spindle bearings and lubrication

[martin_05]

Rebuilding my RF30 clone prior to CNC conversion.



I am replacing the bearings. I bought spindle oil and I have white Lithium grease. I have no clue what was in this thing before. How should I lubricate when I re-assemble this?

Do I use spindle oil only and no grease? Is there a specific type of lithium grease I should use? I just got some from the auto parts store.

Or do I pack the bearings in lithium grease? If so, where does the spindle oil go?

When people install one-shot lube systems it seems that everything, spindle, ways and ball-screws gets exactly the same oil. What oil might this be?

Up to this point I thought the machine was going to use a combination of grease and oil. Not sure what goes where now, particularly when I think about one-shot lube systems.


Thanks,

-Martin

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[Bubba]

Martin,
The bearings in the spindle get GREASE only and in a limited amount. Don't pack them like we used to for front wheel bearings on autos! You don't need spindle oil (nor do you want it as it will wash the grease out......Ask me how I know).
IIRC the fill rate is about 25% and then after you reassemble the quill, you need to run in the bearings. What I did was to chuck it up in the lathe. I maxed out at about 2000 rpm before I reinstalled the quill in the mill and continued on up to my max of 4000 rpm. Below is the recommendations that I found:

Typical run in for spindles is a starting point of about 400 rpm,
up to max in 500 rpm increments, in steps of 30 - 45 minutes.
Check housings for excessive heat as you go.
Then reverse and do it over!
Watch temperature. If it gets hot, stop let cool and do over.

Above is the procedure I followed and after I was done, I found the info below. During run in, I monitored the temperature with an IR non contact unit and kept track of the temps.

The Fafnir Superprecision Machine Tool Bearing catalog suggests that with optimal design,
bearings running synthetic low friction grease ought to be able to run about 20 degrees C
over ambient or about 40 degrees F. In fact, they suggest a proper break-in procedure temperature of 130 degrees F.
involves running the spindle until it reaches 150 degrees F, turning it off to cool, and repeating the cycle
until the spindle stabilizes at 130 degrees F or lower operating temp.
The ideal equilibrium operating temperature is 95 to 115 degrees F. Maximum temperatures should not exceed
170 degrees F. Timken's published specs for tapered roller bearings, including bearing life specs, assume an operating
temperature of 130 degrees F.


HTH

OH as an afterthought, you mentioned one shot etc. I use way oil in my one shot to lube the ways, ball screws and where the quill runs in the head casing on my RF31.

[martin_05]

The bearings in the spindle get GREASE only and in a limited amount. Don't pack them like we used to for front wheel bearings on autos!.

Thanks! I was thinking about packing but it seemed like a bad idea due to additional drag. The run-in procedure is useful.

The text you quoted says "synthetic low friction grease". Any recommendations?

I guess I bought a gallon of spindle oil for nothing. Oh well.


Back when I used to fly gas powered model airplanes I used to break in all new engines by taking the head and carb off, chucking the shaft on the drill press and running them up and down a speed range while submerged in light motor oil. While other guys had constant starting problems at the field all of my motors always started right up and ran silk smooth.

-Martin

[Bubba]

Martin,
Here is the stuff I used and got it at Advance Auto as I remember.

Grease used is "SuperLube" by SyncoChem Company Bohemia, NY Grease | Oil | Synthetic Lubricants LA101-6 or 8

Synthetic Multi-Purpose Grease

Super Lube® Grease is a patented synthetic NLGI grade 2 heavy-duty, multipurpose
lubricant with PTFE. Synthetic base fluids and the addition of PTFE micro powders
combine to form a premium lubricant that provides longer life protection against friction,
wear, rust and corrosion. Machinery lasts longer, downtime is reduced, and productivity
is increased. Super Lube® is compatible with most other lubricants and will not run,
drip, evaporate or form gummy deposits, and will not melt or separate.

Super Lube® is Food Grade, rated H-1 by the USDA and NSF for incidental food
contact. It is an excellent Dielectric and operates over a temperature range from -45° to 450° F.

[SCzEngrgGroup]

White lithium grease is about the LAST thing I would use - it has a tendency to dry out, and turn into something like dried Spackle. Use a good bearing grease. I like the red or greed high-pressure grease available from most auto parts stores. No need to use anything fancy, or expensive, like Kluber, on these small, low-speed machines. It will gain you nothing. Really, in these machines, almost anything will work, as the stress is extremely low. Put in only enough to be sure everything is coated. Do NOT "pack" it. The space between the balls should be filled no more than 20-30%. Turn the bearings by hand to get it distributed, then put everything back together.

Regards,
Ray L.

[martin_05]

White lithium grease is about the LAST thing I would use - it has a tendency to dry out, and turn into something like dried Spackle. Use a good bearing grease. I like the red or greed high-pressure grease available from most auto parts stores. No need to use anything fancy, or expensive, like Kluber, on these small, low-speed machines. It will gain you nothing. Really, in these machines, almost anything will work, as the stress is extremely low. Put in only enough to be sure everything is coated. Do NOT "pack" it. The space between the balls should be filled no more than 20-30%. Turn the bearings by hand to get it distributed, then put everything back together.

Regards,
Ray L.

These are the oils I purchased:



I guess I made a mistake. I thought I was following what I read in another thread. Now I gather that I don't need the spindle oil. Can I use the Vactra 2 oil for ways, leadscrew/ballscrew and spindle cartridge outer surface (the sliding surface)? I'd like to eventually install a one-shot system, which mandates the use of a single lubricant for everything.


Thanks,

-Martin

[Bubba]

"Can I use the Vactra 2 "

That is what I use in my one shot,

[martin_05]

"Can I use the Vactra 2 "

That is what I use in my one shot,

Alright! I made ONE good decision! Brilliant!


-Martin

[martin_05]

After doing some research I found this bearing grease:

Mobiltemp SHC 32

The Mobil Industrial Grease Lubricant Application Guide singles it out for spindle bearing application.

The other grease that is interesting is Mobilgrease 28 Synthetic Aviation Grease.

Mobilgrease 28 - 12.5 oz tube


I am leaning towards SHC 32. I might contact Mobil and ask about conditions where you don't run your machine for months (which could happen in a home shop).


-Martin