Dear Tool Timers,
This weeks tool comment comes with the compliments of our own 3M
Company. If some of you folks don’t know about the 3M Co. their name
stands for Minnesota Mining & Manufacturing. They have a many
facilities right in my own back yard here in St. Paul Minnesota.
Most people think of us as living way up north and yet we always go
"up north" for vacation to Canada or Northern Minnesota.
Anyway, I received some sample radial bristle discs to try and found
they work great. Gesswein and Rio both sell them and the price is
similar from both sources. Buy em by the bag.
They look like a small polishing brush you would use on either a
flexible shaft or on the end of a small mandrel on the polishing
motor. This brush is a charged rubber and has what I would call comb
like teeth instead of solid bristles. The abrasive is all the way
through the wheel and not coated, so as the wheels get old they still
work. I found that they retain their shape well with repeated use
also. For that matter, I haven’t worn out the samples yet after
They come in different sizes and different colors to denote various
grits. It seems like too many grit selections, but for platinum work
the finer grit will be a great asset. The hole through the center has
two different sizes for the disc to screw on to the mandrel. This
goes into either in your flex shaft or polishing motor mandrel chuck.
I used them primarily at the bench. If you use them in the polishing
room they can screw right onto either a plastic spindle or mounted
What I found them the best for in my jewelry world is to pre polish
casting before the polishing room. They got into lots of small areas
unreachable by other abrasive wheels. In between prongs was one tight
area. I don’t like to polish with the flexible shaft because my main
bench is not exhausted and polishing compound gets in my face and I
end up breathing the compound. Now the 3M wheels still remove
material but I didn’t notice a lot of air born particles floating
around although I’m sure there were some. A small bench vent would
probably be recommended for all bench grinding, but I only have one
jewelers bench vented at my shop and it has no flexible shaft yet.
With any bench grinding or flexible shaft work please wear safety
glasses! I think most Dental Labs are set up better. The wheels left
a nice smooth matt finish ready for tripoli polishing. The tripoli
polishing went a lot faster also.
I used them both single and I also stacked them on the mandrel. I use
a quick release Faro hand piece so you need to have the 3/32nd size
mandrel. If you use the #30 hand piece mandrel size doesn’t make any
I still needed a more solid wheel to keep some of my corners sharp. I
wish all small rubber and stone grinding wheels used 3Ms’ numbered
abrasive system. Most wheels and stones I use I just guess at the
grit. With the 3M discs their color and code help a lot with choosing
the right wheel. These 3M discs will round things a bit but all in
all these are a welcome addition to my tool selection.
Thanks to Rick Phil. for the samples. Anne Hollerbach also commented
more extensively on this product a while back. It may be worth while
to look up her comments in the achieves if anyone wants more
TR the Teacher,