Homemade dropout alignment gauge

[us56456712]

It doesn’t have to be pretty to work.

 

[us56456712]

I spread the rear triangle. The above gauge shows it’s perfect on both sides but the drops are no longer parallel. I made a tool out of junk to straighten them.

 

[horsefarmer]

 

[Indyjps]

Pretty cool set up.
I use the string method to get the rear triangle square. Then a piece of all thread with big washers to check dropout alignment by eye. Bend with very big crescent wrench, recheck with all thread washer deal.