In article om, Bay Area Dave wrote:
FINALLY! the voice of reason. well said, Steve

dave

Steve wrote:

I have two 12" combination squares, a Starrett that I use for
woodworking, and
a Sears that I use for rough carpentry. The Starrett is square +/-
0.001" over
its entire length (90 degrees +/- 17 arc-seconds). The Sears deviates
from the
Starret by 0.011" along its length (90 degrees +/- 3 minutes 9
seconds).

For anyone keeping score at home, 99.9% of normal people use a speed
square for rough carpentry since they don't want to bang up their combo
square in a rough carpentry environment.

A marking pencil or knife is going to be significantly thicker than .001
rendering that sort of accuracy useless for woodworking. Additionally,
unless you're using a robotic arm to mark, the line is going to waiver
as your arm moves the knife or pencil. You can also add in blade
deflection, wood movement, etc. and figure out that .001 accuracy is
complete overkill in woodworking.

So get the cool .00000001 accurate tools if you want but please don't
think that they're going to do any better for you than a .01 tool.

Maybe I should have been a bit more specific.... I use the Starret square for
aligning my woodworking tools, principally the jointer and the table saw.

Then again, maybe you should have read more carefully, too, and not made up
your numbers. I said a square accurate to 3 minutes (0.05 degrees) isn't good
enough in my opinion, but one accurate to 17 seconds (0.005 degrees) is. I
didn't comment on the adequacy of "a .01 tool" but for the record I'd imagine
it's good enough. But you won't find a square at Sears that's that accurate.

Accuracy of results will be no better than accuracy of setup. If you're
content with your results using squares from Sears, fine, more power to you. I
bought the Starrett square specifically because I was *not* content with the
results I achieved using the inaccurate stuff from Sears to set up my tools.

I am very pleased with the results I get using better equipment.




--
Regards,
Doug Miller (alphageek-at-milmac-dot-com)