"Elrond Hubbard" wrote in message
...
I just posted pictures of the two tetrahedra that have been discussed in
the "Woodworking Geometry Question" thread over the last few days.

Once I figured out the trigonometry, it took about half an hour to
actually
make the second one. They are 18" on a side, scrap white pine.


That brings back memories. Many years ago I was asked to make a number of
wooden pyramids out of 2 X 2 stock. I just got an ancient radial arm saw
and stupidly said I would do it.

I had never cut a compound angle in my life. I did not know the math. I just
knew the top and bottom angle. So I set up my T bevel to the angle I was
trying to cut. Then I just went at it and cut them every way I could think
of. Total trial and error. I figured if I went at it long enough, I could
come up with a solution. I filled up three boxes with my little angled
blocks. This went on for a week.

Then one night as I was going to bed, I got a clear picture of how to set up
the saw. I threw on my bathrobe, ran down to the basement and cut the angle
perfectly. I went to bed, got up the next day and cut all the angles. I
then drilled the holes and finished the pyramids and delivered them to a (I
am not kidding) pyramid shop. (It did not last long.)

The great revelation?? I got a picture of how the saw would see it. A
horizontal perspective. I was trying to calculate everything by looking
down on the wood. A vertical perspective. When I squatted down and looked
at it across the table, directly at the blade, it all started to make sense.
My original approach/perspective was 90 degrees off!

To this day, if I have any trouble figuring out a cut, I still squat down
and look directly at the blade and figure the cut out from there. It ain't
high math or engineering. But it gets the job done. My farmboy approach.
Totally different than what happened on this forum this week.
Ahhhhhh........, progress.

Lee Michaels