bearings: different grades & qualities

I have to replace some bearings in a generator I have. I discovered they are a
common size - 6302-2RSH. What I want to know is, do
bearings come in different grades or qualities? Or are they all the same? I want
to replace these bearings with the best I can get.
Thanks for any pointers.
Reply to
tg
Loading thread data ...
I don't trust those girls that answer the phone at the manufacturers. I'd rather just go for the best I can get - if I can get advice about what's available. If I ask a local supplier they will only tell me what they've got, rather than what are the best type.
Reply to
tg
I found that customer service reps at manufacturers that I call for suggestions, are actuially either helpful or can take me to competent engineers.
i
Reply to
Ignoramus13628
Define "best". Longest lasting? Smoothest running? For some applications, the cheapest are the best choice because that's all they need.
Also, assuming you've decided you want eg the longest lasting ones, how far up the price/performance curve are you actually prepared to go? If the normal ones are a fiver, are you prepared to pay 100 quid for ones which may last twice as long?
(and a side question : I know ball bearings come in different qualities - do the sealed ones have the same range, or are they rather more standardised?)
cheers, clive
Reply to
Clive George
common size - 6302-2RSH. What I want to know is, do
want to replace these bearings with the best I can get.
6203s are very common and inexpensive bearings. You can get those in the price range from $2-3 at the low end to maybe $12-15 at the high end. Just ask the guys at the bearing house you buy from. This is certainly a case of you get what you pay for.
FWIW a generator shouldn't need super quality bearings. If it were me I'd get the el cheapos. They will last for many years.
GWE
Reply to
Grant Erwin
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "tg" saying something like:
common size - 6302-2RSH. What I want to know is, do
They certainly do.
Avoid RHP for a start. SKF are good, but Toyo are the best.
I can tell you from some time I spent directly involved in making the things that Toyo were the most exacting specs.
Reply to
Grimly Curmudgeon
In message , tg writes
Umm... in essence yes. Or rather you get what you pay for:-)
It is 25 years since I had a proper job; working for SKF at Luton so a certain amount of rust may have affected my knowledge.
Different manufacturers use different steels and hardening methods which confer different characteristics to the life and robustness of the product. Also the fit between the balls and the grooves has a big impact on the noise and performance. Quiet bearings have a shorter life.
I would avoid Japanese; Asahi for instance.
SKF used a through hardening steel whereas RHP used a case hardening process.
There is a massive mark up on bearings. Employees were entitled to 60% discount on deep groove and 40% on tapers.
Care is needed when fitting replacements as simply whacking them in with a steel hammer is likely to cause damage.
Others may care to advise.
regards
Reply to
Tim Lamb
I believe that bearings from a _reliable source_ are generally of good similar quality. Your question reminds me of some interesting info (if memory allows). A certain British army tank had to rely on a source of Russian bearings, as they were not available anywhere else, at short notice. I think that the "cold war" was still on.
Sylvain.
Reply to
Sylvain VAN DER WALDE
I think that you're worrying unnecessarely about quality. I do know that "Timken" make (or did make) good tapered roller bearings. You're talking about ball bearings, I assume. You can also get parallel roller bearings, tapered roller bearings, needle roller bearings, thrust-type ball bearings, etc.. The ordinary (journal) ball bearings can have different clearances (they're marked with a number of zeros on their circumference). If they are a loose fit, they will have a small clearance (between the balls and the inner and outer tracks). and if they are a tight interference fit, they will have a greater clearance to allow for this.
Sylvain.
Reply to
Sylvain VAN DER WALDE
common size - 6302-2RSH. What I want to know is, do
want to replace these bearings with the best I can get.
As to grades you should fit a matching grade to what you are replacing - or ask manufacturer for the grade.
Just throwing money at it is not the right thing to do ... you want the bearing to match the parts it is designed to work with ... what is point in putting in something 10 x the price it needs to be.
As another poster said Toyo bearings are good ... I used INA bearings on most jobs
formatting link

Although I usually go to local Bearing Supplies drop the old ones on the counter and ask for replacements - simple as that.
Reply to
Osprey
Blind posted because top and bottom are boring...
Higher bearing grades generally mean higher RPM with less heat generated. It usually has to do with the surface quality of the balls or rollers in the bearings... And of course the "race" that they run in.
Match the RPM of your machine to the rating of the bearing and you should be fine. Use a higher rated bearing if you wish for longer life. Going much beyond a single grade above is probably a waste of $$$. ...You could actually go to ceramic bearings if you want to simply give money way though. :)
Regards, Joe Agro, Jr. (800) 871-5022 01.908.542.0244 Automatic / Pneumatic Drills:
formatting link
Spindle Drills:
formatting link
V8013-R
Reply to
Joe AutoDrill
In message , Clive George writes
Bearings are sealed depending on their application and intended lubrication. eg. an electric motor bearing might have the dirty *windings side* sealed and the clean side open for grease lubrication.
Internal construction has not cropped up yet and my bearing book is over in the workshop, steel cages, brass cages, nylon/plastic, fully filled etc. etc. AFAIR the numbers give the o/d, i/d, width and abutments and the letters refer to the cage and sideplates.
regards
Reply to
Tim Lamb
Care is needed when fitting replacements as simply whacking them in with a
Use a copper or brass drift (punch) the same size as the bearing track (a tube would be best, but you would need a lot of them). If the outer track is an interference fit, tap on that. If the inner track is an interference fit, then tap on that one. If both tracks are an interference fit (Ford Transit rear hub bearings, for instance), use a drift wide enough to cover both tracks, taking care not to damage the balls' cage. Of course, if you have a hydraulic press with suitable fittings, so much the better (only to put the bearings in their housing, I suppose). I nearly forgot: Aluminium casings should preferably be expanded with the use of heat, before fitting any bearing.
Sylvain.
Reply to
Sylvain VAN DER WALDE
What do all those other bearings have to do with it? He needs 6302s. Those aren't tapered roller bearings, needle bearings, thrust bearings or the like.
GWE
Reply to
Grant Erwin
True in the 70's, not now. Maybe avoid Chinese low-end manufacturers??
Certainly not in small sizes! Anyway RHP are now owned by NSK.
When I was doing basic research on rolling element bearings in the 70's and 80's the general consensus was that there was little to choose between the big names (SKF, NSK/RHP, and FAG). Timken specialise in big case-hardened taper rollers typically used in the "tough" end of the market.
Agreed on both counts
Reply to
Newshound
I'd not heard that one (sounds a bit Urban Myth to be honest, as Wyko could make anything at a price, but maybe it was to do with delivery), but when I was trying to source asbestos clutch linings to keep an old UK nuclear power station going I was interested to find that you could still fit asbestos to Challenger tanks
Reply to
Newshound
All ball bearings are made from SAE 52100 steel. Check with the ABMA or ISO and see.
The fit between the balls and the raceways is called "clearance". The comment "Quiet Bearings have a shorter life." is not correct.
The measurement of noise levels (quietness) in a bearing is a function of the roundness of the raceways and the finish of the raceways, the roundness of the balls and the finish of the balls, as well as the noise generated by the lubrication. The better the finish of the raceways and balls, and the better the roundness of the raceway and balls, means the running accuracy of the bearing is better, therefore quieter. Measuring noise in a bearing measures the balls as the move in relation to the raceways. The noise in a bearing is measured by a transducer that measures the vibration that occurs as the balls move. That measurement is in micron/meters/second.
NSK, Koyo and Nachi make good bearings and are Japanese.
There are no case hardened ball bearings that I know of. You are mixing up ball bearings with Tapered roller bearings.
This guy needs a good sealed for life EMQ bearing. If he's press fitting the bearing on a shaft on a generator he needs a C/3 clearacne bearing. Any major brand...SKF, KOYO, NSK, FAG, Torrington, Etc. will suit his needs.
Reply to
K. A. Cannon

Site Timeline

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.