"Phisherman" wrote in message
...
On Sun, 15 Mar 2009 12:21:58 -0500, "MikeWhy"
wrote:

"-MIKE-" wrote in message
...
I guess my point is... so far the only advantage anyone can offer for
having a granite top is to dampen vibration. So why would you give up
all
the advantages of a magnetic top, just to dampen vibration caused by
faulty or poorly designed parts?

It might be helpful to ask it the other way, too. Why NOT granite? Who
knows. The only thing that comes to mind is not being able to tap a
threaded
hole in stone. I don't typically drop heavy, sharp cornered steel tooling
on
the tablesaw. The only jig I have that fits that description is the big,
heavy tenoning jig. So far, I managed to not ding the C.I. top with it. I
also move somewhere else for heavy hammering. Why NOT granite?


Granite might crack, chip or break, wears faster than iron. Vibration
can be caused by many factors including case design, material, mass,
belt design, tar buildup, rpm, bent shaft, damaged blade, etc.

My lathe sometimes has a vibration issue. It helps to have a variable
speed motor--sometimes changing the speed eliminates the vibration
completely. It helps to have a pair of 800 pound cast iron legs with
a shelf full of sandbags.

Chipping and cracking was first on my mind as well. But how? In normal or
even extreme use, how or what will cause it to chip or crack? Just how tough
or fragile is this stuff? It's only a matter of time before the woodworking
magazines bombard one with ball bearings and bowling balls. I'll sit on the
fence until then.