wonder why you couldn't have a device with two blades on a pivot with a way to fasten the roto rule across the blades to make up a triangle. Then "simple" trigonometry could let you adjust the ruler to get a desired angle. This would be where you may have calculated the angle you want but not have a reference from which to get it.
And, obviously you could measure an existing angle with it too if you actually needed the measurement. Yeah, you can find relatively accessible protractors, but something like this might be pretty easy to fabricate if we get it figgered out correctly, and might be very accurate? So Dan Rossi, help with the gtrig. Let's assume most work would need angles less than 90 degrees as you can always subtract from 180 and measure the opposite angle. There must be something wrong with this? Thinking caps on plese. We could build a prototype and document it here at Smith-Kettlewell if nobody beats us to it. tom
