Wheel Bearings-mix or match?

[Leaky88]

I attempted to get an answer from Timken and National using one of those “GFYS” Contact Links forms companies hide behind. Still waiting…could be a non-work day for Beijing employee tasked with providing a response.

 

I was taught Bearings and Races come as a set and are not to be mixed.  Also, new bearings of unlike brands are not to be mixed, as tolerances and metal may not be the same between companies.  All my purchases until now consisted of a box containing a Bearing and it’s Race.

Has this changed?

AZ sold me 2 National 15101 Bearings.   I asked where it’s Races were and was told they are sold separately and then offered  2 Timken 15245 Races.  
 

I found the same thing on O’Reilly and NAPA sites, Bearings with no accompanying race. 
I know most Aftermarket Rotors come with a Race installed, but I’ve punched them out and installed my own matched set. 

So what’s the deal?
 

Thanks

[Haggar]

Leaky,

 

yes bearings used to come in sets.  Tapered rollers were always available separately too though.  (It has to do with their design.  Proper clearances are set during assembly so the surfaces just need to be good)  It is really amazing, but the newer manufacturing processes allow "matching" of bearings just from their normal stock.  The bearings are manufactured just that much more closely to their design numbers.   I have had to learn to adjust.  Amazingly though I have not had obvious issues with high speed spindle bearings that used to come in "matched sets" but now just come individually.  The manufacturing tolerances are just that much better.

 

Tapered rollers have also suffered from stocking issues.   1 cone part number can be used with 3 to 7 different cups.    I can stock 1 cone part number (buying 10 at a time) and 2 each of the cups that work with it, and have less capital invested in stock that may or may not move quickly.  I can keep that in a smaller area too. 

 

HTH
Hag

[Leaky88]

Thanks.

 

 

 

 

 

 

[Silverwolf2691]

Just for a reference, the company I work for makes micro hydraulic valves. Pressure relief, check, vent, solenoid, etc. We don't work with the CNC machines you would probably picture when some one says CNC machine. Our lathes are a type called swiss screw machines, and ours are anywhere from a bit bigger than a 48" wide two tier toolbox to the size of a small shed (ride on mower can park inside with enough room for bikes on the side comfortably). They are normally used to make screws for mechanical watches. They can hold concentricity to .0003". We have held one part to Ø.05225 ± .00025 for a size tolerance, but usually we stop in the ±.0005 area. After that it gets expensive. Machining has come a long way and holding tighter and tighter tolerancing is getting easier, but it takes the right equipment.

 

In terms of mixing metals, I'm not sure but I'm guessing that it used to be a bad metal combination and tolerancing, but now I think its just tolerancing. Most companies are probably using the same or similar spec stock to make their products. Costs and possibly customer complaint.

 

The other thing is that bearings are standardized in size. Machinery handbook has over 100 pages on bearings in general..  

[Leaky88]

OK.  
With +/- .00025 tolerances, my concerns about current day machining tolerances are assuaged.
I’ll put the damn AZ Bearings from 2 different manufactures and call it done.

Appreciate being brought up to 2021. 

[Silverwolf2691]

Fair warning, that's what we can do at my job, with our machines.

 

 Machinery handbook was less than helpful but I didn't look at the rest of the bearing spec. Only has ID and OD specs, which are sub .001 interference fits.

 

Timken and National are good brands so I don't think you will have an issue. 

[Dieselfuture]

7 hours ago, Silverwolf2691 said:

Just for a reference, the company I work for makes micro hydraulic valves. Pressure relief, check, vent, solenoid, etc.

Make some boost foolers/elbows  I'm in process of making one right now from some menards parts.

[Silverwolf2691]

If only.. they keep us on a tight chain in here.. Plus I only draw up parts, I'm no engineer.  

[Leaky88]

I was in a Shore Intermediate Maintenance Activity in Little Creek Va in 85.  
It was a “massive” Machine Shop that made parts for ships that were no longer available from manufacturers.  

Sailors would bring in old valves, parts from boilers, you name it.  More often then not, they were critical parts from propulsion plant that prevented the ship from getting underway.    It was amazing to watch them machine a new part from a failed part, and to such exacting standards.  I can only imagine the advancements since then. 

[Silverwolf2691]

The more interesting thing is how much still has to be done by hand. With the size of our parts, all burrs have to be removed. We have 3 or 4 ladies in my building that their job is to look through a microscope all day deburring parts with an x-acto knife. All of the valves in my building are hand assembled and tested.

 

But for the most part its all the processes, just able to be done faster. Well except some of the CNC lathes come with laser cutters. No joke on that either..

 

 

[Leaky88]

I’ve keep this part in my tool box since 89.

While in Cuba, I had an Old Willys Jeep.

Engine had real issues, and guy wanted it gone, so I bought it.

After I got into the engine, the part (pictured) was on each

of the Main Bearing Saddles. It’s function was lock the main bearing half 

in place.  But one saddle was missing one, which explained the noise.

There was no Internet, and any attempt to find from the States was in vain.  After exhausting every avenue, I

remembered we had a Ship Repair Facility.  Knowing they too are kept on a close leash, I, with “hat in hand”,  found a 

Machinist and explained my dilemma, and showed him the part.   He took measurements, made a perfect part,  and

then made a second one (one pictured) by sight only.  He never measured the second free-hand one until he

took it off the machine. It too was spot on.  Drove Jeep for 2 years afterwards thanks to that Machinist.