What's the deal on bearings?

[Dan Forsh]

So after finally having done my first crank bearings purchasing an arbor press and fabricating my own version of a crank pusher I champing at the bit to start changing the bearings on a few other projects that I know need doing.

Rather than pay the OEM prices I'm now trying to gen up on bearing speak and work out which generic bearings are needed.

At the moment I'm looking to buy a quantity of 6202 and 6203 bearings to sort out a few saws. I now know the difference between open bearings and the variety of sealed bearings such as RS, 2RS, Z, ZZ/2Z.

What do I also need to be sure of specifically for this application before I buy?

The bearings I removed from the saw I recently did were C3 bearings. Reading up on one suppliers site they say:

"C3 bearings are bearings that have an additional internal radial clearance to cope with high speed environments where excess heat is generated.

They are not suited to environments where critical alignment is required from the onset e.g. Where blades and cutters are set up to each other.

Applications like motorcycle wheels or bicycle wheels do not require C3 rated bearings.

Unless the bearing you are replacing specifically says C3 on it then you should not replace it with a C3 bearing, C3 Bearings are loose to the feel from new and often people complain at the quality of the bearing being poor and having more movement than the one they are replacing. This is the characteristic of a C3 bearing."

So C3 or not C3 for cranks? I guess if I get any of the sealed versions I can just pick the seals out, right?

 

[Lakeside53]

Most C3 work fine, and yes pick out the seals and flush the grease. Buy a TOP brand - not "no name" "made in china". Try to choose bearings with at least SOME internal radius, not a tiny abupt edge - look at the oem and you'll see what I mean. Riveted steel caged bearing are much better then plastic, particularly for concrete saws

 

[Dan Forsh]

Most C3 work fine, and yes pick out the seals and flush the grease. Buy a TOP brand - not "no name" "made in china". Try to choose bearings with at least SOME internal radius, not a tiny abupt edge - look at the oem and you'll see what i mean. Rivited steel caged bearing are much better then plastic, particularly for concrete saws

Oh you're good! Sussed me out just on a couple bearing references.

Are you saying go with the C3 or just not to be concerned about using them?

The brand I changed out were NTN I think these are a good quality German brand? I know I can get SKF and NAG.

The NTN ones are marked up as TS2-6202JRU C3. JRU maybe relates to the radius?

 

[Lakeside53]

If you go to the NTN website, you'll be able to decode the - TS2 xxxx JRU. Each letter usually refers to a specific characteristic. Non-standard radius is not generally available except to OEM, and are specified for two reasons : reduction in stress at the edge point, and mating to the to the crank machining radius

Yes, C3 is the correct choice.

 

[Chilly]

Often the OEM bearings will have additional info in the bearing code. I usually use C3 bearings in my rebuilds.

Chilly

 

[Dan Forsh]

Often the OEM bearings will have additional info in the bearing code. I usually use C3 bearings in my rebuilds.

Chilly

I'm just going off the info in the IPL, for example it only gives 6202, nothing about C3. It's always good to get this kind of info from you guys who have the experience.

 

[Lakeside53]

Here's the suffix/prefix NTN data:


http://www.ntnamerica.com/pdf/2200/dimcodes.pdf

You can get the TS2 - Temperature Stabalized (200c), the J - Steel cage, but the RU is customer specific mods, like champher, special external diamension or shaft fit, etc.

As you've figured out, the "6203" is just a size.. and there are literally thousands of variations based on this size.


The Cx is the bearing internal fit, not the outer or inner bore fit.

BTW, the last 2 digits of the 6k series ("03") represent the size in mm of the inner bore when multipled by 5.

 

[motosierra]

How about using ceramic bearings?

 

[Lakeside53]

Doesn't change that you need to find the right size bearing. You can put ceramic balls into exisiting bearings - search AS for old threads on this.

 

[motosierra]

ok..thanks for the information..

 

[Stihl #1]

Well, by now you are probably realizing that there is way too much information to learn about all there is to know regarding bearings.
But to add to what Andy has said, here is some more info from a STIHL lesson on bearing ratings that may be helpful:

"In ball bearings, as the radial clearance increases, the axial clearance increases as well. The more room between the balls and the rings (radial clearance), the more the elements can shift in relation to each other. Generally, internal clearances are designated from C1 (the tightest) through to C5 (the loosest or largest). The 'normal' clearance is CN, a range sitting between C2 and C3. It is worth noting that if the bearing clearance is not stated in the bearing reference it can be assumed to be normal clearance (CN). With a higher clearance there is more tolerance of thermal expansion effects on the rings and rolling elements. When noise and vibration must be restricted, lower clearances are necessary. Ultimately the specific application and operating conditions determine the appropriate internal clearance.
A micron is one millionth of a meter. A human hair is about 50 microns wide. For a typical crankshaft bearing on a STIHL application, the total internal clearance will be less than 45 microns."

It is the design engineer's job to select the right bearing for an application, and I feel that most quality machines have the right bearing in them. As Andy said, you can find lots of bearings with the same size dimensions. A $1 bearing will fit the same as a $10 bearing. So if you are not going to order a bearing by part number from the OEM, you may easily miss something that could allow the bearing to fail prematurely.
HTH

 

[Lakeside53]

So.. I was on the hunt for 6204 bearings today... not for a saw - but for a Bridgeport replusion motor (very cool design). I need CN or C3, sealed/shielded bearings.


Napa - SKF - $27.45 - made in Argentina; their in-house brand - CGG - Made in China, no class info - $4.95

Ace Hardware - $10.55. None in stock. Box says "Product may be from Korea, Poland, China, Taiwan, Malaysia or OTHER countries". I went there because I've occassionally found top quality GMN bearings in packages.. but most of what I find is China.

Shucks - SKF - $15.95, Made in Argentina - only one in stock, just shields with no seals.

Carquest - NTN - $16.95, Made in Japan, rubber seals (I wanted rubber seals ON metal shields). No-name rubber, Made in China -$3.95


Oh well it was Sunday...

To the web..

Ebay: I can buy 10 for less than $20 - China.. junk...

Grainger has the exact bearing I need (electric motor quality) for $10.85, in stock at my local warehouse...


NOT ONE of these was made in the USA, but I'll trust SKF or NTN no matter where it was made.

 

[brncreeper]

NOT ONE of these was made in the USA, but I'll trust SKF or NTN no matter where it was made.

Are Browning and Dodge still made in the states? I used Browning Gold Labels on the stump grinder.

 

[Bowtie]

How about National bearings?

 

[Bowtie]

Reason I ask is thats what Im using in my boat anchor 029S rebuild I discussed in a different thread.

 

[Lakeside53]

No idea.. what does it say on the bearing or package?

 

[brncreeper]

Looks like Browning is made in Mexico. Seal Master and Dodge are USA made.

 

[Lakeside53]

Grumble grumble grumble

So.. I was on the hunt for 6204 bearings today... not for a saw - but for a Bridgeport replusion motor (very cool design). I need CN or C3, sealed/shielded bearings.


Napa - SKF - $27.45 - made in Argentina; their in-house brand - CGG - Made in China, no class info - $4.95

Ace Hardware - $10.55. None in stock. Box says "Product may be from Korea, Poland, China, Taiwan, Malaysia or OTHER countries". I went there because I've occassionally found top quality GMN bearings in packages.. but most of what I find is China.

Shucks - SKF - $15.95, Made in Argentina - only one in stock, just shields with no seals.

Carquest - NTN - $16.95, Made in Japan, rubber seals (I wanted rubber seals ON metal shields). No-name rubber, Made in China -$3.95


Oh well it was Sunday...

To the web..

Ebay: I can buy 10 for less than $20 - China.. junk...

Grainger has the exact bearing I need (electric motor quality) for $10.85, in stock at my local warehouse...


NOT ONE of these was made in the USA, but I'll trust SKF or NTN no matter where it was made.

I picked up my Grainger NTN bearings.. made in Taiwan...


Oh well, not Made in China.. :monkey:

 

[RiverRat2]

I picked up my Grainger NTN bearings.. made in Taiwan...


Oh well, not Made in China.. :monkey:

LOL!!!!! :monkey: :monkey: :monkey:

 

[bcorradi]

Speaking of bearings...I just recently purchased a higher end clutch for my f150 and it came with a chinese throwout bearing. I have a hard time going through all that work and installing a bearing that says made in china on it. I think i'm just going to pick up another non chinese bearing, if I can find one.