On Thu, 21 Feb 2013 10:35:36 -0500, Greg Guarino
wrote:

On 2/20/2013 9:49 PM, Zz Yzx wrote:
On Rob H's blog he posted a pic of "pins and feathers" used to split
rocks.

I did my disertation on granite, so it caught my eye. IDAGS and found
this:

http://www.youtube.com/watch?v=cBMcMGBhUVk

The guy splits a 26,000 lb chunk of granite with a 2 lb sledge in an
hour. Amazing.

Not quite as straight as he'd have liked, eh? That's probably less of
a problem for foundation rocks than if the stone was being cut for
thin countertops. I wonder if he turned it over and tried to
straighten the left piece...


See more in ABPW.

For the musically inclined - listen to each strike he makes on the
wedges, especially the light "practice" strikes. Each makes a different
"note".

That's how he can tell the pressure, by sound. Similarly, mechanics
judge the flexing of the wrench/extension/socket/bolt to know the
proper torque by "feel".

--
The more you know, the less you need.
-- Aboriginal Saying