From:
"George Graham" <georgergraham@zzzzzzzzzzz>
Date:
Fri, 23 Sep 2005 22:32:10 -0400
Subject:
Pitching. Cutting etc.
Bill asked ,
Quoted text begins.Do you know about "bumpers"?
End of quote.
Bill,
When I stumbled into the monument industry, all the veterans used the term
bumper when refering to any kind of bush chisel used with an air hammer. I
always assumed that the name came from the way the hammer bounces around
when you use it.
I'd like to tie this in with the compressor thread going on. I was spoiled
from the beginning regarding having enough air pressure to get the maximum
work done as fast as possible. I learned air hammer carving in a shop that
had a monster compressor. Bumping down a surface was the first step and the
most aggresive. I was expected to use my 4 point bush chisel,(bumper) with
the air throttle wide open. As soon as contact to the stone was made ,
violent bumping around starts, and it was my job to keep controll and not
knock of anything important, like corners, edges and any nice polished areas
that were meant to stay that way! Learning to keep enough pressure on the
hammer, and still let the chisel bump and bounce freely is the secret. Of
course when I got within an 1\8th of an inch of finish depth, I'd switch to
a 9 point chisel and cut back on the pressure. Then I'd go to a cup chisel,
then a 1 or 2" flat chisel to clean up. I always had unlimited air pressure
to work with, so my air hammers would cut into the stone with the least
amount of effort from me.
My opinion is that for almost all circumstances, air hammers work best at
maximum pressure. It's my job to switch to a smaller hammer and use a
lighter touch as the project dictates, but the air pressure stays high.
The point I'm trying to make, ever so slowly, is that I want my compressor
to at least double the cfm requirments of the air tool you are using. To
get the best and easiest use of my 1" air hammer, I need a compressor that
puts out about 30 cfm. Basicly double the cfm use of my hammer. The
compressor can stay ahead of you and be coasting while you use up air in the
tank, and not be running flat out all the time which shortens the life of
the machine in a big way.
My goals now are to be able to carve with any tools, air , electric and
good old hand tools and not be thinking about what my tools and hands are
doing, but what's happening to the stone.
Good carving to all,
George Graham
- References
- message 00730: Pitching. Cutting etc. - abknight (22 Sep 2005)
- Previous by Thread: message 00730: Pitching. Cutting etc. - abknight (22 Sep 2005)
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