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Why not to polish with a flexshaft?

Was: Holding metal while finishing

Could you explain why you don't like polishing with a flexshaft? 

The above came to me offlist, but I thought it would be more useful
to reply publicly, as it’s a useful topic - I’m going to copy it to
the sender, too.

I don’t “not like” polishing with the flexshaft, first off. The
flexshaft is a perfectly fine tool, and I periodically do detail
polishing with it. I also understand that some people work in
certain ways, and some people only have a flexshaft available -
hobbyists and others. There is no right and wrong for every

The problem is with a point of view that it is the proper tool for
polishing situations where it’s really not, which is usually.
Imagine taking a man’s ring that weighs 3/4 ounce, whatever shape it
is, and trying to polish it by rubbing with toothpicks. Would you
carve a 14 lb turkey with a paring knife? Would you paint your
living room with a #0 sable brush? Not likely. And the same is true
with doing major polishing on a flex shaft. Again, if it’s all you
have or it’s just how you like to work, you’ll get no argument from

On our polishers we have a huge variety of wheels, accumulated over
the years. We have mandrels that take any sandpaper in 1/3 sheets,
6" cratex wheels, platinum wheels, on and on. On a simple gold
wedding band I can sand the outside in 10 seconds with the mandrel,
lap each side to completion on the split lap, which does the whole
side of the ring all at once, leaving it flat and prepolished in
around 5 seconds. Understand that time is a factor, but it’s the
quality - the lap leaves a mirror edge, and the entire ring is on
the wheel at once. The big muslin wheels will take a domed area down
to perfection in about the same time, and remove all faceting at the
same time. Painting your living room with a #0 sable brush is going
to leave brush strokes every 2mm, or else you’d have to spend an
inordinate amount of time dealing with them. Get a roller and put
that paint on the wall.

The other issue is power. In essence the polishing lathe has power,
and the flexshaft has speed. I WILL put a brush on the flexshaft to
get a high-speed, detail finish on a platinum ring. I will NOT sit
down with it that way in the early stages. I’ll get a 6" muslin buff
with white diamond on it, and lean on that sucker till it gets good
and hot on the lathe. That’s power, and it is your friend (and
enemy, as the safety issues raised have reminded us). Polishing
actually removes metal, buffing actually moves metal, and it takes
power to do that. Using a flexshaft in that situation is like
landscaping with a children’s beach trowel - rent a Bobcat and be
done in an afternoon, instead.

So, this posting is not to start some argument - don’t throw me
emails about how you think the flexshaft is the way for anything and
everything, 'cos I don’t care if you like to polish with a scrap of
suede and elbow grease - that’s your business, and good for you. But
it is my answer to the question raised at the top. Don’t carve a
turkey with a paring knife…


Good response. Use the proper tool for the job. I used to try to
polish earrings on my buffer until I had enough of them fly off into
never never land. I paid my son $5 for each one he found. I have
since wised up and use my flexshaft for small detail polishing. But
everything else gets done on the buffer.

Rick Copeland
Silversmith and Lapidary Artisan
Rocky Mountain Wonders
Colorado Springs, Colorado

John, your post gave me a good laugh! What you say is spot on; more
horsepower and bigger is better when polishing.

There is a possible negative which is trying to polish off scratches
left by 220 grit sandpaper using the polishing motor. Some people
prefer to spend time generating vast amounts of heat by using tripoli
instead of 400 and 600 grit sandpaper, and will obliterate any
sharpness that may be required in the finished product. It comes down
to a little elbow grease and fiddling around vs burnt fingers at the
big motor.

Using a flex shaft for polishing is quite feasible as long as you go
though the proper sanding steps. 220 If necessary, then 400, 600, and
for the flex shaft go to 800 grit before using little mops with
tripoli and rouge.

Cheers, Alastair


Don’t forget those nice 3M radial bristle disks if it is
appropriate. Use at high speeds, like 3/4 stepping on the gas. The
light green ones (I call Mint Green) give off a beautiful polish.

Safety tip here. Dust masks, yes, but you can also use Better
Breathers. They go up your nose (I know not the best visual, so don’t
read this over dinner), and you have a lot of facial flexibility in
seeing those tiny scratches using magnification.

Use a larger motor for the bigger stuff, flex shaft for the tiny

Karen Christians
Waltham, MA

scratches left by 220 grit sandpaper using the polishing motor 

Never touch the stuff…Emery paper, usually #2. I pull out the
carborundum when I need it for what it’s made for - steel, sometimes
wood. I’m not going to get into that much, either because school
people tend to grow up with carborundum and swear by it - it’s cheap
and every hardware store has it. After using emery for a time it’s
easy to see the difference, though. People here have taken this
thread well, but I want to say again that the whole field of
polishing is vast and impossible to pin down. There is no right or
wrong, and much of it has to do with who’s hands are holding the
work. One might use bobbing compound and white rouge and I would use
white diamond and zam on the same piece, and get equal results. And
then, if we were to try each other’s methods we’d both fail at it.
There are some good practices, though - and one of those is not to
paint your living room with a #0 brush…