Originally Posted by
Andrew R Stewart
I have a 171 tool and have used it only a few times to measure seat tube angle. Works well as long as you level the drop outs.
I would lone to have a 170. Not too hard to make, I know. To answer Kontack- The tool knows the angle because it sits on center with the steerer and upper blade, which back then were in line with each other. But the head tube angle need not be know as the trail is read directly from a scale. Once trail is known a head angle can be calculated, if needed.
I think it's cool to see these old tools. Reminds one that what we talk about here is the same as what was talked about 50 years ago. Andy.
Yeah, I was thinking about blade-to-steerer angle, like on a Colnago fork. But there must be forks that had some curve high enough up to cause the measure to be off even if they didn't look like straight blade forks, like the Henry James 3° crown.