"CAMCOMPCO" wrote in
oups.com:

So is this a vote for not "ballizing" the hole with a bearing.....Dan,
what say you. Have you had success with it? It's interesting to note
how opinions on certain topics can generate both support and
condemnation at the same time...

Thoughts and comments from others...I guess I am going to cram a ball
in the hole, cut the "tube" open and check with a microscope
myself....Once I get my ball bearings in, I'll check and get back to
you all with the findings.

By the way, I never commented on the material....mostly CRS, SS or
Aluminum (mostly fortal these days).


It's a crude form of burnishing. Thousands upon thousands of parts are
burnished everyday. This type of thing would be a big no-no in a medical
implant where impurities can get "rolled in", or in a critical
application where surface integrity was important, say in a tool steel
that was to be heat treated later. On materials that work harden it may
raise the hardness slightly. In all likelyhood the Aluminum might not
work as well as the stainless or CRS.

The trick is to get the hole straight, to the right size, and finish to
start with. That might take a little experimentation.

As far as burnishing a bearing surface, It's done all of the time. It's
how .0001" diameter tolerances are held on Swiss screw machine on the
tiny shafts inside clocks and watches. It's also how many manufacturers
of power tools size the shafts that run in race bearings.

The downside to using a ball is that it will happily follow a crooked
hole, and a big high spot in the hole will tend to push the ball over to
the lower side.


--

Dan