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Lapidary wheels?

hello, all- those of you who are experienced in cutting your own
cabs- can I run 6 inch wheels on a machine designed for 8 inch
wheels? I have an old Covington/Beacon star machine that I would like
to convert to diamond wheels- but they are sooo expensive. Also- If
any of you are willing to help a novice cutter offlist, please email
me! I appreciate all help/advice- Thanks in advance.

Re your question about running 6" wheels on an 8" machine…yes
you can do that. Having said that however, you would do well to do a
bit of checking to see if the wheel covers, water feeds, etc will do
the job for which they were designed. You could find for example,
that with the smaller wheels, water will splash all over the place.
Also if the water feeds are above, as in many Star machines, the air
pressure caused by the rotation of the wheels may blow the water away
before it gets to the surface of the wheel. These are just some
things to think of. Not sure what someone else might also come up

I understand the problem with purchasing 8" vs 6" wheels but in my
personal opinion, the larger wheels will give you a looooot more
service. They will last for years if cared for and your cutting will
be much easier and faster due to the higher rim speed and larger
surface area. It depends on your objectives. If you want to discuss
more you can contact me offlist at @coralnut.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry.

Yes you can run smaller wheels, I assume you are using the green
grit silicon carbide grinding wheels.

You will probably have to adjust the water feed so it makes proper
contact with the cutting face of the wheel.

If I can help don’t hesitate to make contact…

Cab cutter and jade carver from way back…

Keith Torckler, Cornwallis, New Zealand


can I run 6 inch wheels on a machine designed for 8 inch wheels? 

As long as the the wheels will fit the shaft they can be used. Most
wheels come with several bushings of different sizes to accommodate
shafts of different diameters.

The only negative effect you’ll see with the 6" wheels is cutting
time. A 6" wheel has roughly 6" (8-6=2; 2 x pi=6.28) less surface
area than an 8". This translates into longer cutting time with 6"


To make the transition to diamond, you might want to consider
diamond belts on an expanding drum. As the name implies, the drums
(8" diameter x 3" wide) expand when they’re rotated, locking the belt
into place. Stop the drum and the belt slides off to be replaced by
the next grit. A little more time consuming, but the investment will
be significantly less than buying all the necessary wheels. This
works really well if you’re cutting several stones at the same
time… and the expanding drums are kind of resilient, making it
easier to avoid flat spots as the drum kind of “gives” around the
piece being cut when you apply pressure. You can also use cheaper
silicon carbide belts with the same drums for rough work, sanding
metal, etc.

HTH (Hope this helps),

Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)