25,000 RPM Bushing materal?

[Cooter Brown]

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[Bob Korves]

I tried Quality ball bearings made by skf and that doesn't work

If they are sealed bearings, factory packed with grease, you will probably have problems. Open bearings would be best, with a few drops of oil added to the air inlet every time you use it, and add a few more drops every 15 minutes or so if you are using it for longer than that. High speed bearings need cool air brought to the bearings to keep them cool. Grease causes too much friction at high speeds, and adds resistance to free bearing movement, friction that becomes heat. Make sure you use clean air for your air tools. The interior of the tool needs to be kept clean. Install an inline filter near the shop air outlet or the tool inlet to keep junk out of the bearings and the vanes of the motor.

 

[Downunder Bob]

Just check are the SKF bearings intended for that speed, with high speed bearings. If the bearings are rated for that speed, and you are using a suitable light spindle oil then you must have some slight misalignment in the shaft. Does it spin really free. when spun by hand? Are your bearings sealed sometimes the seal can cause friction.

You don't want grease or even a heavy oil, you should use a very light oil, sometimes loosely called spindle oil. When I as working as a tool maker we used many die grinders, they were all air driven with an oil mister in the supply line. the exhaust air actually came out through the bearing and kept everything cool.

 

[Cooter Brown]

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[Downunder Bob]

Maybe the misalignment is in the housing the machined space where the bearings fit it wouldn't take much especially with deep groove bearings. If it is chinese made that could be the problem. what oil are you using?

One more thought, are you sure the heat is coming from the bearings, could it be from the motor?

 

[Cooter Brown]

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[Ulma Doctor]

i have a turbo-charger disassembled on the bench as i write this.
turbochargers are known to have significant speeds incurred during operation, often bordering on hundreds of thousands of rpms.

in the turbo i have apart, there are bronze bushings that have radial orifices drilled for circulation of engine oil.
the tolerances are fine, less than .001" clearance anywhere.

i'm sure 954 aluminum bronze would stand up to the service
i'd recommend lapping the bushings to dimensions and using turbine oil

or possibly using graphite impregnated bronze bushings

 

[magicniner]

i have a turbo-charger disassembled on the bench as i write this.
turbochargers are known to have significant speeds incurred during operation, often bordering on hundreds of thousands of rpms.

in the turbo i have apart, there are bronze bushings that have radial orifices drilled for circulation of engine oil.
the tolerances are fine, less than .001" clearance anywhere.

i'm sure 954 aluminum bronze would stand up to the service
i'd recommend lapping the bushings to dimensions and using turbine oil

or possibly using graphite impregnated bronze bushings

That's a great idea, it will work fine, if you have an oil pump to supply the hydrodynamic bearings you are describing and a sump for the oil to drain into

 

[Cadillac]

That's a great idea, it will work fine, if you have an oil pump to supply the hydrodynamic bearings you are describing and a sump for the oil to drain into

Super charger on my wife’s Mini Cooper has self contained oil resv for front and rear bearings. Just changed at 60k maybe a tea spoon each.
Maybe look into ceramic bearings

 

[Cooter Brown]

the first couple people had some good replys after that people didn't even read the thread..... I'm out...