(X-posted with the Mechanics forum)

I just came across a nice, light steel frame yesterday and I'd like to use it for a project. The catch is, it's got canti bosses and they're both totally fuxx0rd.

On the one hand, this is good, cuz I think I want to use dual pivot calipers anyway. On the other hand, it's not drilled for calipers.

So what I'd like to do is drill for calipers and grind off the messed up canti bosses. The question is, how do I figure out if the seatstay bridge is in the right place? I could probably fab up a canti mount, if I had to, out of carbon fiber or something (I don't have the facility to weld or braze. That comes later.) but I need to know where it belongs first anyway.

I also need to know if there's any reason that the bridge wouldn't be able to take the drilling.