Hi Tim,

Yep, this is the classic test cut method and it can produce very
accurate results. You've improved on it a bit by including precise
measurement of the final cutoff (via micrometer or calipers) and the
use of a dial indicator to monitor the fence adjustment. Personally, I
can't help but feel that it's actually a more costly and time consuming
method. Sure, you avoid buying a large square but you could still
obtain accuracy to within thousandths with a smaller square (+/-0.001"
at 6" is +/-0.003" at 18"). And, there is some cost in cutting up a
peice of sheet goods every time you want to square up your sliding
table (not to mention the investment in time). The ordeal would make
me reluctant to check my alignment (which I do frequently) and
reluctant to change the setting (cut angles). The indicator/square
method is quick, easy, accurate, and economical - which means it will
be done without hesitation whenever it is necessary.

Thanks,
Ed Bennett


wrote:
Ed,

I looked yesterday afternoon and it worked fine for me.

For squaring the fence on the sliding table, I'll suggest another
approach that doesn't require an 18" precision square.

Take a rectangular panel (plywood, particle board, masonite, etc.) that
is about the maximum your table will cut. Using the roughly-squared
fence, do a trim cut on Edge 1 of the panel. Now rotate the panel 90
degrees so Edge 1 is against the fence, and do a trim cut on Edge 2.

Repeat until Edge 4 has been cut and is against the fence. Now cut a
narrow strip off Edge 1. Measure the width of both ends of the strip.
If they're the same, your fence is perfectly square to the table
travel. If there is a taper, the fence isn't square.

I believe if the leading edge of the strip (first part into the blade)
is narrower than the trailing edge, the fence is set to greater than 90
degrees, and vice-versa, but I could have that backwards.

I clamp a dial indicator to the sliding table to measure the outboard
end of the fence, so as the fence is rotated the dial indicator will
tell me how much. Because of the geometry of the parts, there's no
formula and you have to do some trial and error, like in the current
video. Make an adjustment on the fence, make the five cuts, measure
the strip, and repeat if necessary.

I found that writing down the measurements helps a lot to see the
trends and how much an adjustment on the fence changes the width of the
strip.

Because of the repeated cuts, any error in squareness of the fence is
quadrupled on the width of the strip. A micrometer or vernier caliper
is useful for measuring the strip. This method gives you very accurate
squareness on the fence.

Otherwise, it's a great series of videos.

Cheers,

Tim


wrote:
Hi Folks,

Just thought some of you might be interested. No charge, it's an
on-line video (for those with high speed connections). No spam, no
harvesting. Nothing but interesting (and hopefully useful) videos.

http://www.ts-aligner.com/videos.htm

Let me know if you have any questions.

Thanks,
Ed Bennett