Ivan Vegvary wrote:


wrote in message
ups.com...
I'm looking to put together a set of ball bearings between about 4/16
and 1", in as small increments as possible for removing dents from
brass instrument tubing from the inside. What size increments do
readily available - i.e. "off the shelf" ball bearings normally come
in?

One supplier has said in that size range they have 16 bearings - 1/4,
9/32, 5/16, 3/8, 7/16, 15/32, 1/2, 9/16, 19/32, 5/8, 11/16, 3/4, 13/16,
7/8, 15/16, and 1 inch. I see there are several gaps where the size
jumps by more than a 1/32. I was hoping to find a set that more evenly
covers the sizes. Is this a realistic goal? I'd like to find them all
at once instead of piecemeal it together so it would be worth the
time/bother for whoever sends them to me.

Would I be more likely to find a greater number of increments in metric
or inch sizes? In fact, if I included both metric and inch sizes, would
that be likely to fill in "gaps" in sizes?

Thanks for all input.

Brassplayer,
Sorry I cannot give you advice. But interested in knowing do you plan on
pushing the balls, pulling the balls, how do you retrieve if they get
stuck?
etc. etc. etc. Sound like a lot of fun.

FWIW, there seem to be two commercially available systems that use
high-powered magnets to pull the balls,
http://www.magneticdentremovalsystem.com/ and the other is called the
"Dent Eraser", googling which gives a large number of sources, including an
announcement of a demonstration by its inventor, then a professor at OSU,
back in 2002--seems like it's a fairly recent innovation.

There's a pretty good discussion of this at
http://www.saxontheweb.net/vbulletin/archive/index.php/t-5820.html. Note
especially the comments about the strength of the magnets.

It seems that one does _not_ need an exact fit for the tubing in
question--apparently one uses the magnet and ball in a manner more
analogous to working sheet metal with a hammer and dolly, so getting stuck
shouldn't be an issue if one is using the system in the way that was
intended.

One manufacturer of musical instrument repair equipment
http://www.ferreestools.com/magnetic_dent_tools.htm seems to be flat out
scared of the physical danger represented by the magnets and won't sell
them at all and another will only sell to "qualified personnel" however
defined.

Ivan Vegvary

--
--John
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