Automotive Style Air Hammers

[Greg Carter <greg@zzzzzzzzzzzzzzzzzzzzzz>]

I was wondering if anyone has used the pistol grip style automotive air
hammers for stone work?  They are fairly cheap, in North America you can
pick up one for $12-$40.  They use 0.400" shank bits though.  Are stone
air hammer chisels that are advertised as 1/2" shank actually a true
1/2"?  Is my hope of finding a cheap alternative dashed?

I used one recently.  I know George said to hand point it, but I only
had a small 3/8" point, no bushing chisels.  I did try to do it by hand,
but I'd still be hammering away.   So I used my auto air hammer and the
point bit that came with it.  The bits are only hardened steel.  So I
basically destroyed the bit on my piece of stone.  But I've owned both
the hammer and bits for about 8 years and never used it while working on
a car, plus the bits are cheap (~ $1).

Here is the style of hammer I'm talking about
http://tinyurl.com/fmkr3

Close up of the finish left
http://tinyurl.com/kaqvx

Wider view, the top is polished at this point. Oh and I did remove the
drill marks with a torch later.
http://tinyurl.com/fgxm2

The hammer has an adjustment knob on it to vary the force and beats per
minute.  If I turned it down all the way I could work close to edges
without too much fear.  I used one hand on the gun and the other on the
bit to help guide it.

This was my first attempt at making something out of stone besides just
trying to make it square.  I made some mistakes, like cutting too close
where I wanted the raised letters with the diamond blade.
http://tinyurl.com/kwxhz
So I didn't get the profile I wanted.  I'll also look for an alternative
to a Sharpie marker for marking the stone... I think I spent around 2
hours with 30 grit diamond pad on the polisher getting rid of any trace
of it.  Doh.

If you're curious here's a web page with most of the photos from my last
post and this one plus some of it installed.
http://www.carter-engineering.com/stonefountain.htm