Try it and see. An alternate idea would be to use thrust bearings to take
the side load.
There is a web site with a guy making and selling what he calls a Home Brew
Linear Bearing. Check it out:
http://www.buildyouridea.com/
It is larger than what you describe but maybe...
--

Ron Thompson
On the Beautiful Mississippi Gulf Coast
USA

http://www.plansandprojects.com

Where did everyone go? Oh, yeah.
http://groups.yahoo.com/group/castinghobby/
Y'all come, ya hear?
*******
"Steve Lusardi" wrote in message
...
If I were to do this, the answer is no. The bearing contact pressure is
too
high and the contact area is too small. It is cheaper and more reliable to
use a plastic sleeve as a bearing. There are many self lubricating
plastics
today that easily handle very high loads and do not require hard surface
rods to ride on.
Steve
"Alex" wrote in message
om...
My question is about life expectancy on following linear slide setup:

Two parallel 5/16 rods and a slide that uses a pair of small plain
ball bearings(5mmx12mmx5mm) on the same
axel with the spacer between them instead of a each single grooved
roller.
The
ball bearings will roll on the both side of the rod since the spacer
will
be
shorter than rod diameter.

It's a preloaded design with preload no more than 10-15lb.
Speed is 1 foot/sec.
It's manually driven device and "high mileage" is not expected.

I understand that radial BB are not made this kind of thrust load but
since
it's a relatively light load I think that it should work fine.

What do you think? Is it acceptable compromise?