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
circumstance.
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
me.
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…