It could be those repressed memories of that technique being discussed here
many, many times have just reemerged.

"David Binkowski" wrote in message
.com...
I just thought of one good way to determine if a square is square...
On a flat surface, with something clamped to it at 90 degrees, hold
the square against the flat surface and the clamped item. Draw a
very fine line using the edge of the square. Then turn it around 180
degrees and draw another line right over the first. If there is any
deviation from square, the lines will diverge. It should be readily
apparent since the amount of the error is doubled. If both lines
are exactly parallel, the square must be good.

--
The software said it ran under Windows 98/NT/2000, or better.
So I installed it on Linux...

"Bluetobb" wrote in message
om...
I am a beginner wood worker. I was told one of the essential tools
beyond any power tools is a good machinest square. So... I went to my
local Woodcrafters and purchased a $60 Starrett Machinest 6" square. I
was happy with my purchase and excited to use it to better set up my
TS. When I started using it to check alignment of the fence with the
miter slot I found what I think is a flaw but it might be so small
that it is to be expected and/or does not matter for what I am doing.

When I placed the steel ruler of the machinest square in the slot
width wise. As if I was ripping the ruler on the TS but had it stood
up on end. One end of the ruler fit in the slot perfectly and I could
not twist the ruler at all, it was locked in, the only thing I could
do was pull it up out of the slot. But when I put the other end of the
ruler in the miter slot at the same spot the fit was loose. I could
spin the ruler in the slot. I hope I explained this well if not I will
try again.

Is this a reasonable amount of imperfection in a $60 machinest square?
I am guessing it is only difference of less than 1/32 of an inch but I
am not sure. Any advice would be much apprecaited.

Thanks
Dan