Re: [CAD_CAM_EDM_DRO] RE:Re: skate bearings

> Tony Smith wrote:
>
>>ABEC1 is rated at 30,000-40,000 RPM, I think ABEC9 are rated up around
>>100,000 RPM. Basically, the higher rating have better tolerences and
>> more
>>accurate machining, meaning less run-out, vibration etc. The higher
>> ABECs
>>are for lab gear, dentist drills etc that have high RPM. For 'linear
>>bearings' on a www.crankorgan.com style machine, anything will be ok.
>> For
>>a high RPM spindle, ABEC would matter.
>>
>>
> To run rolling-element bearings at these high speeds, you pretty much need
> oil-mist lubrication. These bearings would have no integral seals or
> shields,
> and a stream of air carrying a fine oil mist would be pumped through them.
> Perske and Danly/Onsrud routers use this, for instance. The air provides
> continuous cooling, and the oil assures that there is JUST enough
> lubrication,
> without enough to cause the fluid friction you'd get with an oil-immersed
> bearing.
>
> Jon

Yep, you don't get those speeds with grease! Heat starts to become a
major issue, etc. You need to be fairly serious to embark on oil-mist
cooled bearings, and most hobbyist type aren't running spindles at 40k.
Running at 20k with ABEC1 shouldn't be a problem, unless you want less
run-out.

Dentists drills are air powered, and the air is used to cool the bearings.
Not sure on lab gear, the speeds can be high but the loads aren't great
in those cases. Usually spinning a few ml of liquid, rather than a few kg
of metal.

A bearing in my vacuum cleaner (<2000 RPM?) finally ran out of lubrication
and exploded a while back. It must have gotten a bit warm, it was a
lovely shade of blue.

Tony