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I'm ok with stiffness but how could a roller bearing damp without lubrication. Could I have more details about this phenomena.

I used to make a vibration reading on each of my spindles after the run-up procedure. I always see noise around 240000 cpm. Could this noise be a cause of concern? If I understand, the only way to catch lubrication issue is to compare results? If the overall demodulation value increases from one...

What about the cost? Is there a big difference?

Hello, Does someone have ever tried the spiralock threads. I read they work well but I'd like to have a feedback from the practical world.

Look in the skf general catalog, you'll find anything you need about choosing the right oil viscosity for ball and roller bearings.

Rob, you said there is an increase in noise with roller bearing, is it the same with ball bearings?

Hello Folks, Could someone tell me how to identify a poor lubrication with fft? I've been told that noise in acceleration is a good sign but I have no more details. I'm looking maybe for an articles that develop on this subject. Vibration litterature I have doesn't say nothing about...

FAG seems to have a really great software as well. I never tried it but it seems to be interesting. Go on the website for more details.

There was a unique oval spal on the bearing closer to the tool. I'm still invertigating to find out what it is. Don't you think that if the grease would have turned yellow because it's overheated, the bearing raceways should be discolored? The raceways looked pretty clean, just a clowdy white...

Hello folks, I just breakdown a spindle. On one side the grease (NBU 15) was white, which is the initial color, but on the other side, the grease turned yellow. Does someone know why? Overheating? Thanks,

I'd say that you should not have only one bearing to withstand moment load. The tilting effect will change your contact angle and considerably reduce the BSL. You should contact bearing manufacturers and see what they have to say. I'd be curious to know what they think about that.

Hello Folks, I've been really surprised when I called my malleable cast iron grade 65 manufacturer and he wasn't able to give me the exact coefficient of thermal expansion. It seems that this value is quite hard to find. Does someone know the value or a great reference where I...

I just read someting interesting on the snfa assembly manual found on the link above in the tightening procedure. It says that you have to tighten the end cap bolts three times the recommended torque, loosen them off and re-tighten them to the specified torque. Then, you measure the gap and...

Japan used to put polyamide cage bearings in their machine tool spindles. They use it because they work better with vibration and in high speed conditions. I use polyamide cage once and I noticed that running temp was lower than phenolic cages. Actually, it's true for a certain speed but as you...

The link is http://www.snfa.com/index.php?id=23. you will also find good references for bearing failure analysis. So, if I understand, methods for preloading the locknut may varie from one user ot another one. If you have ground bearings, one might want to torque the locknut enough to rest the...

Diamondjim, you should look further in the SNFA's website cause I found it there and it's in english. Tmoose, I already experimented that problem about the distorsion caused by bolts, it can be controled with FEA analysis easily. I'm more concerned about the gap between the cover end face and...

I agree with you but on some cases, you have to deal with preload caused by tight fit. I got a fretting issue not so long ago, the only way I had to fix it was to increase the interference fit over the manufacturer recommandations. Interference preload is not suitable but fretting is, to me...

I think you got it right. I should have mentionned that preload caused by tight fit usually goes along with angular contact bearings or taper roller bearings.

Diamond, I think I just said something wrong, if you have a loose fit on the shaft, you will for sure have a tight fit on the housing which will lead to radial preload. But I'm not sure to understand what you meant, could you develop a little more.

It depends what you mean, with an angular contact bearing, with some type of loads, you can have a loose fit on the shaft which won't preload the bearing radially but still get an axial preload with the locknut. Of course, if you look at the balls, they are preloaded axially and radially due to...