tapered roller bearings

[henryr]

I’ve spent hours over the last three days looking for tapered roller bearings with tighter than normal tolerances and didn’t find any. Timken and SKF sites list tapered roller bearings with standard and tighter tolerances but I couldn’t find any. So I spoke with their technical support people and was told that, while they list them with tighter tolerances they don’t make them but if someone ordered 1000 they might make them. I’ve also searched many bearing distributor sites, in the US, UK and Japan and even sent emails to a few and got replies that they only have standard class K or class 0 tolerances. Does anyone know where to get tapered roller bearings with tighter tolerances?
Thanks,
henryr

[SteveM]

Not sure of your application, but bearings for Bridgeport heads are high precision (ABEC 7) and are readily available.

I'm sure there are in-stock bearings for other mills and lathes and maybe one of those could be adapted to your situation.

Steve

[henryr]

Seems that angular contact bearings and ABEC bearings are not made in the same dimensions of metric tapered roller bearings.

[Rick]

What is your application? what type of precision are you trying to achieve?
The clearance/preload in tapered roller bearings is usually set by adjusting the axial length of the shaft, sometimes with a nut (front auto spindles). I have never considered taper roller bearings as high precision bearings, not like you would consider a spindle bearing which typically come in matched pairs or triplet sets of angular contact bearings with the preload preset.

[Harold_V]

I have never considered taper roller bearings as high precision bearings, not like you would consider a spindle bearing which typically come in matched pairs or triplet sets of angular contact bearings with the preload preset.

Heh! While that may be true of the common taper roller bearing, the headstock of my Graziano contains a high precision roller bearing, one made with hollow rollers. The spindle has about .0002" runout (the machine is more than 50 years old), so I inquired as to the cost of replacement. They wanted north of $1,600 for the bearing when I made my inquiry about ten years ago. I can live with the .0002".

Incidentally, the speed rating for this bearing is 6,900 rpm. Shocking!

H

[liveaboard]

Which makes me wonder;
Considering most of us simply don't ever work to such exacting standards, would a good quality normal tolerance bearing set do ok?
How much runout would one expect from modern regular high quality tapered roller bearings?

[whateg0]

Which makes me wonder;
Considering most of us simply don't ever work to such exacting standards, would a good quality normal tolerance bearing set do ok?
How much runout would one expect from modern regular high quality tapered roller bearings?

That's what I did on my old lathe. Couldn't see spending$400 on the correct ac bearings so went with a $50 set. The rest of the machine was far worse off than the spindle bearings after that.

[SteveM]

Which makes me wonder;
Considering most of us simply don't ever work to such exacting standards, would a good quality normal tolerance bearing set do ok?
How much runout would one expect from modern regular high quality tapered roller bearings?

That's what I did on my old lathe. Couldn't see spending$400 on the correct ac bearings so went with a $50 set. The rest of the machine was far worse off than the spindle bearings after that.

Yes, using an expensive set of precision bearings on a worn lathe could be an example of putting lipstick on a pig.

Steve

[henryr]

I emailed many distributors, in the US, UK and Japan and Timken, SKF and Nachi technical support, and all told me they only make tapered roller bearings in the lowest tolerance class like 0 or K. It seems there is one company, Gamet, that makes them but cost is around $1000 for one bearing. So i'm considering using angular contact or deep groove ball bearings. My research has started.

[Rick]

I have never considered taper roller bearings as high precision bearings, not like you would consider a spindle bearing which typically come in matched pairs or triplet sets of angular contact bearings with the preload preset.

Heh! While that may be true of the common taper roller bearing, the headstock of my Graziano contains a high precision roller bearing, one made with hollow rollers. The spindle has about .0002" runout (the machine is more than 50 years old), so I inquired as to the cost of replacement. They wanted north of $1,600 for the bearing when I made my inquiry about ten years ago. I can live with the .0002".

Incidentally, the speed rating for this bearing is 6,900 rpm. Shocking!

H

Hi Harold,
My wording was a bit vague or misleading, and based on my mind set of designing machines. I know there are specialty bearings of all types. And I would consider high precision taper roller bearings as a non standard item. My statement was based on 40 years of designing and building custom / specialized automation equipment. The last thing I want to do is put some non standard specialized bearing in a machine and my customer would have trouble acquiring in the event of a failure. You will ask why don't they keep spare on hand? My answer would be the majority just don't, even when given a recommended spare parts list. I have this Murphy like definition of a ball or roller bearings always in the back of my mind " A mechanical rolling element to reduce friction and wear that will ultimately fail at the most inopportune time". That's why I don't consider, in general, tapered roller bearings as high precision bearings. There are typically other ways to accomplish what is needed without using non standard / specialized components especially when designing from a clean sheet.

[RONALD]

Here is an old movie where they show making Gamit bearings about 16 minutes into the movie; should be of interest.

https://www.youtube.com/watch?v=nQaAKUAzK0w

My 1994 Harrison VS330TR has Gamit Bearings below are the inspection sheets.

[pete]

I've watched that YT video before Ron. I seem to recall a mention that there still being made, but those Gamet bearings are pretty famous world wide for there high accuracy and have an eye watering price to match.

The OP still hasn't specified what he wants to use a higher precision tapered roller bearing set up for. Without that it's an impossible to properly answer question, and depending on use there could very well be cheaper or easier alternatives that might suit the application better. In 1910 and probably before that they were using using simple sleeve bearing lathes to bore and grind master gauges to far under sub 10ths accuracy. It's a much more sophisticated and expensive system than any ball or roller type bearing, but Moore Tools purposely uses sleeve bearings today on there high speed nano capable machine tool spindles.