"Doug Miller" wrote in message
. ..
In article , "PDQ"
wrote:
If you mean a miter cut, the length of the miter is

the root of two times the square of the width of the board.

Try again. Square root of 2 times the width of the board _not_ squared.

If you mean a bevel cut, the length of the bevel is

the root of two times the square of the thickness of the board.

Try again. Square root of 2 times the thickness of the board _not_
squared.
Your formulas below are correct (even though given with an absurd degree
of
precision), but your descriptions above are wrong, and don't match the
formulas.

1 inch wide = 1.4142135623730950488016887242097
2 inch wide = 2.8284271247461900976033774484194
3 inch wide = 4.24264068711928514640506617262909
4 inch wide = 5.65685424949238019520675489683879

It appears the bevel/miter is proportional to the width by a factor of =
~1.41.

Yes. Proportional to the width. Not to the square of the width.

Or, the width/thickness is always 70.7106781186547524400844362105198% of
the bevel/miter.

I find measuring to 20 decimal places is usually good enough for me.
Although I only make things like garden furniture and planters etc.

Oldun