Re: [CAD_CAM_EDM_DRO] RE:Re: skate bearings

> For the bearing experts out there:
> What are operating limits of skate bearing?
>
> safe speed/speed to destruction
> radial load
> axial load
>
> Some of these sold to skateboarders have ceramic balls, in what ways are
> these better?
>
> I'd be more inclined to experiment with cheap bearings than expensive
> ones.... There are lots of mechanisms that could use lots of bearings and
> computer control. It'd be a shame to put it together and find out that
> $20
> bearings are needed rather than $1 bearings.
>
> Elliot

Ceramic bearings give the skater street cred & bragging rights, and more
money to the person who sold them. Not much else. I guess the ceramic
balls won't expand when the bearing gets hot, reducing binding.

The lowest grade of bearing is precision (which doesn't mean anything),
and that's all skaters need. You then get ABEC1, up to ABEC9.

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.

For specs on a particular bearing, you'd need to check with the
manufacturer, as bearing come in various materials, eg you can also get
plastic 608 bearings with glass balls, for food processing or around
acids, etc. They'll only handle 200-300 RPM though.

Skaters think that if a bearing can handle high RPM, it'll make them skate
faster. For skating, you actually want a little bit of slop in your
bearing to get free running, along with rubber seals and stainless steel.
People buying ABEC9 for skating are posers, you'd lose that rating as soon
as you put your foot on the floor.

Tony