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Hot Oneway 1640 headstock

Patrick Miller

Patrick Miller

Joined
Jan 20, 2011
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Location
Central Washington State, the dry side.
A question on my Oneway 1640 headstock bearings- I have been turning a few spindles as of late and noticed with the increased speed (over bowls) that my head stock inboard bearings get really hot- after 15 minutes I can barely keep my hand on that head stock. The headstock has always been quite warm but this seems too warm. Sometime back I removed the spindle assembly just to see if I could see any obvious cause which I could not. I did however find a piece of thin brass shim stock that was protruding from between the bearings and had been smeared into the cavity- actually made the spindle difficult to remove. I removed this as my options were limited and reinstalled the spindle. I know a bit about bearing installation but am hardly an expert. I bought the lathe several years ago used but barely. I have sent a couple of messages to Oneway but they have yet to respond- busy after the AAW I suspect. Any of the Forum members have experience or suggestions about this?
thanks!
 
When you had the spindle out, did the bearings seem tight when you tried to turn them by hand. They should essentially turn without any resistance and any drag would be reason to suspect a problem. Also, if you hear any sort of sound -- ticking, dragging, rumble, growling, clicking, or whatever sound (no matter how faint) then that is an indication of possible bearing problems. If the lathe is old and has been operated hot numerous times there is also the possibility that the grease has broken down so that the oil has separated from the soap and leaked out of the bearing.
 
I've been turning on a 1640 for 6 plus years now and yes my inboard side of the headstock gets hot when turning high RPMS. I will turn crow call bodies for 3 hours at a time at high rpm's and the inboard side of the headstock can get very very warm. It has done it since brand new and really not reduced in temp at all over the years. I think it was John Jordan that told me it is the type of bearings Oneway used and not to worry unless I start to get play in the head stock. After several 1000 hours my lathe runs as true as ever. Kevin should get back to you from OneWay, I've always got a prompt response back from him concerning questions.
Jack
 
That is normal and nothing to worry about. Its actually pretty rare for lathe bearings to go bad, and you'll know when they do.

Low clearance=friction x speed=heat. 🙂 The bearings are made and rated to run at pretty high temps. You add a load using the tailstock, too. I would suggest just turning and not thinking about it.

John
 
thanks

Bill-
I popped the plastic grease covers off the bearings and the grease looks fine. Also the bearings are free and quiet so I am thinking Jack and John may be on to something. I'll see Kevin has anything to offer but other that that I am goin' turnin'....
thanks guys
 
John Jordan said:
That is normal and nothing to worry about. Its actually pretty rare for lathe bearings to go bad, and you'll know when they do.

Low clearance=friction x speed=heat. 🙂
Click to expand...

Nope. Coefficient of friction x normal force produces friction. Friction produces heat. No correlation to speed, rather to duration and load (increases normal force) in this instance.

Good heat sink
 
MichaelMouse said:
Nope. Coefficient of friction x normal force produces friction. Friction produces heat. No correlation to speed, rather to duration and load (increases normal force) in this instance.

Good heat sink
Click to expand...

Double nope!!

I am sure that John Jordan's remarks weren't intended to be a physics lesson, but just a simple (and valid) observation. My interpretation of what he said is that basically bearing get hotter when they run faster. I am sure that John was talking about temperature and not energy.

Meanwhile, your nitpicking "correction" is a mixture of a couple facts along with a good helping of misapplication and misunderstanding.

Since you were picking at nits, I'll do the same. Friction doesn't produce heat, work produces heat when some of that work goes into overcoming friction. You stated that speed is not a factor, but then contradicted that when you said heat is a function of duration. Duration implies both time and rate in order to arrive at distance. Heat and temperature are not the same thing although in everyday use they get treated as being equivalent. While the amount of energy (heat) used to overcome friction when moving the ubiquitous sliding block physics model from point a to point b is a constant value (assuming a simplistic view of friction), the temperature rise is a function of how fast we get there (rate).

The actual physics of what is going on in a ball bearing assembly is far more complex than a simple sliding friction model. The grease, for example, reduces wear, but adds considerably to non-linear friction (wrt velocity) in the form or viscous drag.
 
No contradiction save in your own mind. Duration of operation allows for a build of heat. Which I guess is a nit to you, but if it stays home rather than sinks and/or radiates, it'll build to a max. Friction is considered a constant in most equations except where compressible fluids are involved. Then you'll see it as a velocity-dependent variable.
 
MichaelMouse said:
.... if it stays home rather than sinks and/or radiates, it'll build to a max....
Click to expand...

You seem to still be confusing heat and temperature. Heat doesn't build to a max -- it is energy expended and continues to do so as long as work is being done. Meanwhile in a steady state system, temperature does reach a quiescent value when dissipated energy equals input energy.

MichaelMouse said:
... Friction is considered a constant in most equations except where compressible fluids are involved.....
Click to expand...

Did I say otherwise?
 
Bill,

Thanks for elucidating the obfuscation.

Keeping it simple

Faster speed means hotter bearings than than slower speed.

Rub two sticks together slowly no fire!

Also Kevin told me the bearings they use now run hotter than the ones they used previously.

Have fun
Al
 
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I wonder why anyone would change from cooler running bearings to hotter running bearings in the same application?
 
Bart Leetch said:
I wonder why anyone would change from cooler running bearings to hotter running bearings in the same application?
Click to expand...

I'm sure that the choice was made on several factors besides temperature.

Two things that can affect the temperature are tighter clearances between the balls and races and full contact labyrinth seals. Not that those are necessarily the reasons in this instance, but as long as the bearings are not running hotter than their rated temperature, then things should be hunky dory.
 
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