large scale caliper for measuring

I needed a way to measure around a motorcycle  fender to get the distance between fender mounts without taking the fender off, as the bolts mounting the fender are in a counter bore.

this works on 2 framing squares.. the ones I have were pretty heavy duty so I made the gap for the clamps easy to slide on.  there are 1/4x20 threads printed in there, but you'll have to run a tap through them to clean them up.. then use a ¼ bolt or thumb screw to tighten against the squares.