Re: skate bearings

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Roy J. Tellason"
<rtellason@b...> wrote:

> On Tuesday 16 August 2005 11:41 pm, Tony Smith wrote:
> > > Is there any reason you have to use skate bearings? Why don't

you just

> > > get some that are an exact match to what you need?
> > >
> > > Jeff
> >
> > Skate bearing (608s) are cheap and easily purchased. A lot of

motors

> > (vacuum cleaners and the like) also use them. The other common

one is the

> > 607, a little bit smaller than the 608.
>
> What do these numbers refer to?

Others have commented on bearings but you might find these links
useful...
my first job on leaving school in 197x was with a bearing
distributor, it doesn't mean I know any more about them, just that I
know a good value for money bearing when I see it.
in those days skates didn't have decent bearings so there was no
supply of cheap good stuff.

The numbers quoted above are the size codes

see http://www.smb-bearings.co.uk/S_MMET.htm for examples

the ABEC numbers are just manufacturing tolerances..

if you want to know more about them then have a look at

http://www.consbrgs.com/technicaldata/380_br.html

and the pages that that page refers to..

AFAIK ABEC 9 should be OK up to 40,000 rpm or more
provided they are made of good quality materials, and note
that the ABEC rating does not indicate the materials, just the
manufacturing tolerance

The reason I and others use the skate bearing is that they are
ridiculously cheap compared to others and this is directly due to
them being manufactured in massive quantities for skates..
simply economy of scale.

Regards
Chris (-=Spiyda=-)