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Natural Science Forum / Physics / Acoustics / January 2006Ball Bearing "Squeal"
Does any one know the origin of ball bearing "squeal". I have an ancient bench grinder that now makes a prolonged squeal as it winds down after being shut off. I have no idea what is the cause, nor do I have any idea as to how to lubricate it since the bearings are buried deep inside the motor housing, with a grinding wheel bolted to each end of the shaft. Ball bearings these days usually come with the advisory that they need no lubrication since they are lubricated for life (?!?!?!?!?). So, what's the sound source (5-10 kHz and higher)? What to do about it? Angelo Campanella Angelo, > So, what's the sound source (5-10 kHz and higher)? < I'm no expert, but I always assumed it was surface friction. And I assume it's at a high frequency because it happens mostly at the surface so a VERY thin layer of the metal is oscillating. I'll be interested in hearing what others here with more knowledge have to say. --Ethan > Angelo, >>So, what's the sound source (5-10 kHz and higher)? < > I'm no expert, but I always assumed it was surface friction. And I assume > it's at a high frequency because it happens mostly at the surface so a VERY > thin layer of the metal is oscillating. I'll be interested in hearing what > others here with more knowledge have to say. It seems to be Catch 22. The bearing obviously is in some minor trouble, yet it is no where near the end of its useful life. How the bearing manufacturer came to the conclusion that lubrication is to be locked out of the life cycle is beyond me... Could it have been a marketing decision by an overambitious sales department? And what's a felow to do to remedy the siutation? Drill a hole in the bearing cover and squirt in some grase or oil? Ang. C. >> Angelo, >>>So, what's the sound source (5-10 kHz and higher)? < [quoted text clipped - 15 lines] > > Ang. C. Since it is an "ancient" bench grinder, perhaps you should give up on the traditional values that we all had back in the 60's and adopt the throw- away mentality that exists today. Have you tried to get a VCR, CD player or TV fixed recently. The repair will cost you $150 and you can buy a new one for $75. Alternatively, you can try to repair it yourself and pay $30 for the schematic and the same for any specialty parts and waste a lot of your time in the process. If you are really cheap and want to waste even more of your time, you can try repairing yourself without a schematic. > It seems to be Catch 22. The bearing obviously is in some minor >trouble, yet it is no where near the end of its useful life. How the >bearing manufacturer came to the conclusion that lubrication is to be >locked out of the life cycle is beyond me... Could it have been a >marketing decision by an overambitious sales department? If it's squealing, it's in major trouble, probably at the end of its life. Dirt is the enemy of ball bearings. The idea behind sealing them is that they're packed with the right kind of lube at the factory, then sealed so the stuff does not leak out or get contaminated. The same philosophy applies to ball joints and tie rod ends on cars. Remember grease jobs? They're a thing of the past, and the joints last longer now. > And what's a felow to do to remedy the siutation? Drill a hole in the >bearing cover and squirt in some grase or oil? Replace the bearing or the grinder. Not many things last forever. Ken Plotkin > If it's squealing, it's in major trouble, probably at the > end of its life. Not necessarily. > Replace the bearing or the grinder. From a hearing safety viewpoint you could be right. If it is a unaccesible ball bearing yes, but if the tone is caused by the teeth of gears it could have a long lifetime. It is also slightly possible that there may be other safety implications than hearing safety of the noise, ie. whether the machine will disintegrate in an unpleasant way when it fails. > Ken Plotkin Kind regards Peter Larsen  Signature******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* >> Angelo, >>>So, what's the sound source (5-10 kHz and higher)? < [quoted text clipped - 15 lines] > > Ang. C. Get a can of wd40 and spray it all over the bearing. On 1/6/06 10:27 AM, in article ZDyvf.230799$qk4.15632@bgtnsc05-news.ops.worldnet.att.net, "Angelo Campanella" <a.campanella@att.net> wrote: > Does any one know the origin of ball bearing "squeal". > [quoted text clipped - 13 lines] > > Angelo Campanella Maybe you can find out how many balls are in the race. Then from the speed of the motor, you can calculate what frequency you should get. Many modern digital VOMs have a frequency measurement capability. What I haven't figured out yet is how many sound blips you should get per revolution per ball. Have fun! Bill -- Ferme le Bush > Does any one know the origin of ball bearing "squeal". > I have an ancient bench grinder that now makes a prolonged squeal as it > winds down after being shut off. Does it have some kind of gearbox? > So, what's the sound source (5-10 kHz and higher)? My first guess is dry and or worn gears. The dark horse option is a ball bearing that is dry or blocked and rotates on the axle, there will then be grey metal powder near it. Ball bearings generally rattle rather than squeal unless blocked or otherwise affected by a cracked ball. > What to do about it? Lubricate gears, preferably with grease, perhaps cbain grease or similar ultasticky stuff. The White & Bagley Co. of Worcester, Mass. 01608 once upon a time manufactured a great spray oil called Oilzum Vitalube Spray, good pin-point aim (usable at 2 feet) and a mix of some slighly nasty organic solvent and a very clingy oil. Very good creep, ie. probably also good at getting into sealed ball bearings if required. "Not for use on electric motors". Not good to inhale, not at all good but great to solve all kinds of problems on a printing press while it runs. Possibly extinct due to new safety regs. Contrary to most other spray oils that are intended as cleaners or penetrants and looseners only it actually is a usable lubrication. > Angelo Campanella Kind regards Peter Larsen Signature******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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