# Lathe Spindle Bearing Temps



## opensourcefan (Apr 25, 2022)

I was just told by China that it is normal for a Spindle bearing to heat up to 60-70c.

Doesn't seem right to me but I have no experience with this. 

What say you?


----------



## Degen (Apr 25, 2022)

Thats hot IMHO.  I have never seen either my lathe or mill (even driven close top double the speed with VFD) anywhere near close to those temps.  Warm (maybe conbsidered hot) to the touch, but nowhere near that.


----------



## Brent H (Apr 25, 2022)

If your lathe is powered by an internal combustion engine I can see bearing temps in that area but not for a conical or ball or roller bearing.

From the attached chart you will see that it is possible to run a high tolerance conical bearing at 66C for up to 24 hours - that is like the MAX and after 24 hours you probably no longer have a high tolerance bearing.  With proper lubrication I could see a bearing running (with load) at about 35 to 50 C MAX   70C is HOT for this type of bearing use.


----------



## whydontu (Apr 25, 2022)

I’m going to say no way. Spindle and headstock are huge heat sinks, only way a bearing would get that hot is if the bearing is mis-aligned or the lubrication is non-existent. Anyone out there with an IR thermometer want to run some tests?

SKF info for heavy industrial use:






						What’s normal:The role of temperature in bearing applications
					

Maintenance technicians at a glass fabrication plant recently witnessed firsthand how high temperatures can affect and potentially damage rolling bearings....




					evolution.skf.com


----------



## DPittman (Apr 25, 2022)

I can imagine that a really high speed (6000+rpm) bearings could run that hot with no concern but if it is low speed (<3000rpm) I would be worried there is some friction going on that shouldn't be. I'm no expert however.  Are these new bearings and at what speed and load?


----------



## kevin.decelles (Apr 25, 2022)

Plain bearings (babbitt) etc.  -- yes.


----------



## kevin.decelles (Apr 25, 2022)

Check that, you said 70C, not 70F.    My old 1903 Von Wyck gets up past 70F, but not 150F that 70C would imply.


----------



## Dabbler (Apr 25, 2022)

The max temp  a well running machine should get is about 80F, maybe a degree or 2 more.  

That's it.  Babbitt or bronze bushing machine, well when it gets over 80F, time for a rest.  Bert's SB lathe with bronze bushings never got warm to the touch, even after an hour of use.


----------



## opensourcefan (Apr 25, 2022)

Okay, thanks fellas, that's what I thought. Heat is usually the enemy of everything, can't imagine any lubricant would even stay in the bearings at those temps.


----------



## Darren (Apr 25, 2022)

Are they sealed bearing, or oil lubricated? Alignment, or preload is way off either way. I get 5-10c temp rise after an hour or so on both my lathes.


----------



## opensourcefan (Apr 25, 2022)

Darren said:


> Are they sealed bearing, or oil lubricated? Alignment, or preload is way off either way. I get 5-10c temp rise after an hour or so on both my lathes.


I believe they are sealed as there is no way to lube them. The rear will rise 10c in just two 3" med feed passes.


----------



## Tom Kitta (Apr 25, 2022)

Usually when its hot to touch - and 70C is quite hot to touch something is not right - I mean we are talking about a lathe head stock - plain bearings when something is "off" can get hot. But I never had bearings that are not plain get even past "warm to the touch" - so maybe 40C after running for 10h. 

Now look at transmission case in a car - technically 70C should be still OK, even up to 100C - so bearings in there are OK at that temp. But we are not talking about car transmission but a lathe -

I.e. Chinese can be technically correct - it can get hot without damage but in real life, for the machine type, they never should be even close to this hot. 

Same for my milling machine - maybe 40C, maybe 45C. But never so hot I could not hold my hand on the housing for however long I wish.


----------



## Darren (Apr 25, 2022)

opensourcefan said:


> I believe they are sealed as there is no way to lube them. The rear will rise 10c in just two 3" med feed passes.


Something is definitely wrong. Is spindle preload adjustable?

Non oil lubed bearings will run warmer,,,but maybe 40c if its in a warm shop.


----------



## YotaBota (Apr 25, 2022)

I've read a few different forum threads where these lathes are treated like a kit. When you get one you tear it down, clean everything and then align it when putting it back together.
I don't remember reading if this is a gearhead machine? If so have you had the lid off to check that there is oil in it? Please don't be offended by what may seem like a basic question, just trying to cover all the bases.


----------



## Janger (Apr 25, 2022)

See related thread. Post in thread 'Rockford CNC Lathe Revival'








						Rockford CNC Lathe Revival
					

I’d probably go with just the gasket glue, very thin.  On old machinery you can go to town on gaskets, but with precision fits it can interfere if too thick in my experience,




					canadianhobbymetalworkers.com
				




There various members advised 40 or 45C


----------



## Degen (Apr 27, 2022)

I just saw a good YouTube from Suburban Tool about spindle repair and what is done for run in to prevent damage, worth a look for you.


----------

