At 03:26 AM 21/06/2008 -0700, Norris Lockley wrote:
>BUT I have st
>ill to work out how to measure the head angle by trigonometry.
The head angle can be tricky, especially with a small frame. However, if you were to tightly fit a long pipe or stick through the head tube and measure the distance to the seat tube with the help of the t-square at two points a known distance apart, you could determine the length of the short side of the triangle formed by the difference in the head and seat angles. The angle would be small, so you don't worry which is the hypotenuse. If the two measurements were the same, the angles, of course, would be parallel. (Yes, I too have books of logs and trig tables somewhere in the basement, even a slide rule. If that's not on-topic, I don't know what is.)
John Betmanis
Woodstock, Ontario
Canada