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Rules of thumb for setting spindle bearing preload

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
I have seen good spindles made both ways. Heavy duty lower RPM lathes are often made with tapered rollers. Lighter duty, high RPM, very precise lathes often use angular contact ball bearings.
 

rhb

Aluminum
Joined
Apr 27, 2019
Location
A small town in central Arkansas
FWIW I just read the manual for a Clausing-Colchester 11" I'm considering buying. The manual states that the spindle bearings should be adjusted to 0.0001" of free float measured by pushing back and forth on the spindle *by hand* with a dial indicator on the spindle.

To me that comports well with the advice that Eric and Tyrone gave.

Have Fun!
Reg
 

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CarbideBob

Diamond
Joined
Jan 14, 2007
Location
Flushing/Flint, Michigan
Sad face here.
The attachment above is 100% useless information.
OP is on his way to becoming a expert on spindles.
I see no results yet so the jury is out. Perhaps he gets lucky despite all.
The thing that bothers me the most is people who believe reading lots of things is the same as doing it for decades.
No engineer or scientist with any real world experience thinks that way.
I do get chasing these things and gathering all information possible but it is a real world.

I chart temps vs time. BUT other things can run high speed temps if not loaded right or just greased wrong.
So many variables so many ways to go right and wrong.
Doing it is good, we learn from failures. (I did everything right and it is still a piece of shit)

I have no problem with cup and cone spindles or workheads in superprecsion work. It is just different in design and consideration.
The OP is looking to get .0003-.0006 at 12 inches out with 3 inch spacing and going to single end ball style.
Way past a 7 grade even if lucky. Hell my $650,000 tool grinder will not do this.
This a world where you pay $3000 per bearing and like it.

Despite all that have tried to help across a few threads the OP is sort of weird.
I sort of get this to a point as I am for sure a hacker and bend rules or conventional knowledge a bit.

Build it and show us all. Talk is cheap. Looking up lots on the net is for little kids.
Much talk.. time to put up or shutup.
I have tried to help in some way but........
Bob
 
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eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
Sometimes you just have to try something to see/understand how hard it is... Videos from guys like Robin make it look easy. There's a lot of behind the scenes stuff going on there that you don't get to see... Very time consuming stuff.
 

rhb

Aluminum
Joined
Apr 27, 2019
Location
A small town in central Arkansas
Completely agree. That's why your temperature and Tyrone's pry bar struck me as excellent "rules of thumb".

Because of stick slip I wound up getting the bearings too tight. But running for 20 minutes made that clear. They were too hot.

Forty years ago I decided I was entitled to claim to be a "mechanic" when I reassembled a TR 7 engine someone else had taken apart without *any* data. Before that I merely said "i worked on cars". All I knew was it was a gasoline internal combustion engine. I had to peel it down to the block, pan, crank and pistons to reset the timing chain tensioner. I poured a tablespoon of gas down the throat of the carburetor and had the owner turn the key. It lit and purred like a kitten.

Mechanicing machine tools is a whole level above that. While visiting a friend's shop a few days ago I commented that rebuilding machine tools is the "ne plus ultra" for a "mechanic". There is all that geometry and metrology to deal with.

FWIW "ne plus ultra" is Latin for "there is nothing higher".

There is an old saw about people who repeated the same 18 months of experience for 20 years. Twenty years of turning and knurling wrench handles does not a "machinist" make.

Any scientist or engineer who doesn't solve real world problems is a fake. You cannot have "fakes" without the real thing. But the real deal reads as much as they can *before* they start. No benefit to repeating someone else's mistakes or reinventing the wheel.

Any time I was given a new assignment I pulled 20-30 professional papers and read them *before* I did *anything* else. I still have the file folders full of papers for various projects I worked on. Probably time to recycle them. As much as I enjoy the work, I'd rather do other things in what time remains.

I am not Richard Feynman grade, but I have the same attitude. I don't are what other people think. I don't play cards, board games, etc because I don't care about competing with other people. If you don't care about winning, games are boring as hell. The only competition I'm interested in is competing with myself and doing better than I did the before.

Have Fun!
Reg
 

CarbideBob

Diamond
Joined
Jan 14, 2007
Location
Flushing/Flint, Michigan
RHB is so way past any of us, anything is hopeless of us mere humans and he wants no advice.
Have fun Reg.
One word would be to be careful who you piss on and don't piss in the wind.
You have so far done nothing and pissed on many.
So far you show no reason to be here other than to poke your readings.
Build it. Show it. Do not ask for help if you reject it all.
I am not a research scientist. Just a simple man here.
Bob
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
OT (is not about preloading bearings.0..
QT (One word would be to be careful who you piss on and don't piss in the wind.)
And don't piss on the electric fence.
*But this is a free country so do that if you wish and it makes you happy. It is your Constitutional right to seek happiness.
 

triumph406

Titanium
Joined
Sep 14, 2008
Location
ca
Any time I was given a new assignment I pulled 20-30 professional papers and read them *before* I did *anything* else. I still have the file folders full of papers for various projects I worked on. Probably time to recycle them. As much as I enjoy the work, I'd rather do other things in what time remains.

I can only imagine the consternation when you discovered that there weren't 20-30 professional papers on tightening a Grizzly spindle nut.

If there were, you would spend 20-30 hours gaining valuable knowledge from these texts, and two minutes tightening the nut. Sounds about right for a research scientist.
 

rhb

Aluminum
Joined
Apr 27, 2019
Location
A small town in central Arkansas
Personally I don't pass judgement on people of that caliber. Obviously some of you will diss *anyone*.

Feynman was critical to the success of the Manhattan project. He did the calculations using IBM punch card calculating machines.
 

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
Being a jerk doesn't make one less intelligent. Feynman was intelligent, and he also expressed himself well. Sometimes being very smart can hurt social development. Sometimes it doesn't. Some people are just not very social no matter their intelligence. People forget easily that not everyone is just like they are in terms of those factors.
 

memphisjed

Stainless
Joined
Jan 21, 2019
Location
Memphis
Feynman ended up “sharing” his Nobel prize because he stole the math. He was not known as a good mathematician. He got fired from his first assignments at los Alamo’s because of it.
Great lecturer - not so great math guy.

... and I am a steel worker saying that.
 

MCritchley

Hot Rolled
Joined
Mar 22, 2007
Location
Milwaukee
RHB is so way past any of us, anything is hopeless of us mere humans and he wants no advice.
Have fun Reg.
One word would be to be careful who you piss on and don't piss in the wind.
You have so far done nothing and pissed on many.
So far you show no reason to be here other than to poke your readings.
Build it. Show it. Do not ask for help if you reject it all.
I am not a research scientist. Just a simple man here.
Bob
Hey Carbide,

RCH seems to get the experts to come out and post really good information. I don’t read his posts, just the ones from the folks that have been there.

For example, I always have disliked scotch rite around machine tools. After reading your post about it being banned in a high end shop caused me a moment of reflection and thought regarding the matter. If you would not have brought up the fact perhaps I would have never found it out. So I thank you and others for replying to these nutty posts.

So thanks to all of those passing knowledge along, keep it coming.
 

jim rozen

Diamond
Joined
Feb 26, 2004
Location
peekskill, NY
"Personally I don't pass judgement on people of that caliber."

Not a judgement, this was a comment based on a personal encounter.
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
Very likely the heat expansion caused by RPM or whatever would be tested and a preload would be determined for an application, something turning a galizzon RPM might be different than one turning 500. Even pre-loaded duplex bearings are subject to some thought based on the application..
Here are some considerations I found on another website
what speed will brgs operate at?
how much radial load is expected?
how much axial load is expected?
is inner ring stationary relative to load or outer ring?
are brgs press fit into housing, if so, how much press?
are brgs sealed, shielded, open.
this should be enough information to ascertain (guess at) 'normal' operating temperature.

Good Luck!
 
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Mr. J

Plastic
Joined
Nov 4, 2022
Used bearings require less preload than new bearings.
Both Timken and SKF used to have some guidelines online, but I have not seen them for a long time. I went to Timken school....

Some lathes use "Precison" Timkens. These need even less preload than normal Timkens because the grind of the rollers is different. It isn't that they are more or less precise than another style of Timken.

A reset used bearing should not produce much heat upon running as there is no break in to happen. Contrary to some beliefs, break in is a real thing. On new bearings installations, heat is normal, and the spindle must be rotated slowly and turned off to cool. A process that can take a lot of time depending on how much rigidity is wanted in the end. A lathe needs more than a car wheel, but less than an index head.

If you sense heat in the bearing area more than the general gearbox oil (10 degrees F) upon first run, you might be OK, but no more than that. Used bearings don't break in unless they have enough damage that they should have been replaced.

For my lathe with used bearings, I'd tighten until I could measure a very, very small amount of drag on the spindle when hand turned. Maybe best to use a string and spring gauge. A 13" inch lathe will obviously need less drag than a 30"

Run it at the speed you want the happy medium of rigidity and cool temp. Faster will get warmer, nothing you can do about that (except use a warm up cycle). It should have almost no heat buildup at the bearing, like nothing (or almost nothing) more than oil temp. If the oil is kept at a minimum (not a flush or stream), it will heat less. Less oil is better. Just a mist or occasional drop is perfect.

I've built custom spindles up to 50hp and 50-5000 rpm. I've done this a few times.
 
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eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
Break-in procedures for bearings are found in the engineering manual mentioned by John Oder earlier in this thread. There are differing procedures based on bearing type and operating speeds etc. Also slight differences in recommendations between manufacturers.

Also, heat doesn't only come from break-in. All bearings warm up during use, so I'm not sure what that comment is about... Any bearing running at speed will warm up a bit. Even more so with more preload. A bearing running in a large oil reservoir will also keep a lot cooler than one running in a small amount of grease. Break-in may produce a little extra heat at first, but all bearings will get warm and even possibly borderline hot at high speeds. There's a very good reason most CNC machines use oil chillers...
 








 
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