Every time I want to open up a hole, I reach for my Air Grinder or
Dremil and use a 'stone' grinding bit. But it never seems to do much
and wears out quickly.

I was recently at a Motorbike exhibition and there was a tool stand,
which had a range of 'bits' which were completely metal! They came in
all shapes and sizes (balls, cones, cylinders etc) and had various
patterns sliced into them. Some had horizontal and vertical slots cut
in them, leaving a load of sharp edges, and some had a 'cork-screw'
like pattern cut around the outside.

Since then I have been looking for 'bits' like this and can't find them
anywhere. None of my tool catalogues show anything remotely similar.
Does anyone know what these tools are called?

Are they designed for 'grinding' in general, or did I misunderstand
their use?

Any info would be appreciated

Jon

wrote in message
oups.com...
Every time I want to open up a hole, I reach for my Air Grinder or
Dremil and use a 'stone' grinding bit. But it never seems to do much
and wears out quickly.

I was recently at a Motorbike exhibition and there was a tool stand,
which had a range of 'bits' which were completely metal! They came in
all shapes and sizes (balls, cones, cylinders etc) and had various
patterns sliced into them. Some had horizontal and vertical slots cut
in them, leaving a load of sharp edges, and some had a 'cork-screw'
like pattern cut around the outside.

Since then I have been looking for 'bits' like this and can't find them
anywhere. None of my tool catalogues show anything remotely similar.
Does anyone know what these tools are called?

Are they designed for 'grinding' in general, or did I misunderstand
their use?

Any info would be appreciated

Jon


Try doing a search for "rotary rasp" - no, it's not a side-effect of a civic
club meeting - and you might find some.

You might also look for diamond bit assortments: they come in both 1/8" and
1/4" shank sizes.

http://www.american-carbide.com/Burs/Bur.aspx

carbide burr? Rotary file?

google these phrases and you'll get a hatfull of pages.

Dave

wrote in message
ps.com...
http://www.american-carbide.com/Burs/Bur.aspx

carbide burr? Rotary file?

google these phrases and you'll get a hatfull of pages.

Dave

Also, avoid using any kind of abrasive to open a hole where there isn't one
unless you're trepanning. The center of any stone has little to no surface
speed so it won't cut efficiently, regardless of the speed it's driven.
Grinding wheels, or mounted wheels such as you're discussing, behave soft
when driven slowly, so instead of grinding, they slough off, destroying the
wheel.

Harold

wrote:

....
I was recently at a Motorbike exhibition and there was a
tool stand, which had a range of 'bits' which were
completely metal! They came in all shapes and sizes
(balls, cones, cylinders etc) and had various patterns
sliced into them. ....

Sounds like carbide burrs.

http://www.amazon.com/gp/search/103-6356167-0069445?%5Fencoding=UTF8&search-alias=tools&field-brandtextbin=Metal%20Removal ?


--
-- Steve

wrote in message
oups.com...
Every time I want to open up a hole, I reach for
my Air Grinder or
Dremil and use a 'stone' grinding bit. But it
never seems to do much
and wears out quickly.

I was recently at a Motorbike exhibition and
there was a tool stand,
which had a range of 'bits' which were
completely metal! They came in
all shapes and sizes (balls, cones, cylinders
etc) and had various
patterns sliced into them. Some had horizontal
and vertical slots cut
in them, leaving a load of sharp edges, and some
had a 'cork-screw'
like pattern cut around the outside.

Since then I have been looking for 'bits' like
this and can't find them
anywhere. None of my tool catalogues show
anything remotely similar.
Does anyone know what these tools are called?

Are they designed for 'grinding' in general, or
did I misunderstand
their use?

Any info would be appreciated

Jon

I think what you saw were tungsten carbide burrs.
They do take a good size bite. Even the fine ones
leave a rough surface, so it's a good idea to
finish with a stone of the surface finish is
important.

wrote in message
oups.com...
Every time I want to open up a hole, I reach for my Air Grinder or
Dremil and use a 'stone' grinding bit. But it never seems to do much
and wears out quickly.

I was recently at a Motorbike exhibition and there was a tool stand,
which had a range of 'bits' which were completely metal! They came in
all shapes and sizes (balls, cones, cylinders etc) and had various
patterns sliced into them. Some had horizontal and vertical slots cut
in them, leaving a load of sharp edges, and some had a 'cork-screw'
like pattern cut around the outside.

Since then I have been looking for 'bits' like this and can't find them
anywhere. None of my tool catalogues show anything remotely similar.
Does anyone know what these tools are called?

Are they designed for 'grinding' in general, or did I misunderstand
their use?

Any info would be appreciated

Carbide burrs used for cylinder head porting and general metal removal. I
have dozens of them in my head shop and any major engineering tool supplier
would be able to sell you some.
--
Dave Baker

Thats the ones I have looked everywhere and never though of using
'burr' and/or 'file'.

A huge thanks for your help

Jon

wrote in message
oups.com...

Any info would be appreciated

As others have said, they're carbide burrs.

Please wear your safety glasses while working with these things. I would
*strongly* recommend a face shield as well. I use these extensively at work
and have had chips removed from my eye three times. My leadhand had one
explode about six inches from his face. They removed eleven pieces of
carbide from his eye.

I find the chips from carbide burrs to be the nastiest chips in the shop.
They're *very* sharp and very small. They stick to everything with texture
and you'll do well to have a pair of tweezers readily available when doing
lots of cutting. I wouldn't recommend trying to wipe them off your arm with
your hand once you're done. Use running water.

Regards,

Robin

Robin S. wrote:
....
*strongly* recommend a face shield ...
They're *very* sharp and very small. ...

What he said!!

Check eBay for them. I bought a lot of 10 for about $1 apiece. They
are 1/4"diam 3" long, rotary rasp sort of thing. I have broken a
couple, but not worn any out.

Bob