I have a late 70s classic with Campagnolo components. The original Campy pedals mount easily on the Campy cranks, but I can't use them (too small). When I try some current pedals, I find some thread on cleanly and others just don't want to go. For example, I have a pair of MKS Sylvan touring pedals of which the right one installs nicely but the left meets heavy resistance halfway in. There's no junk in the threads getting in the way.
I suppose a good shop would have taps (left and right threaded) that might be used to clean up these threads. I find it strange though that the orignal pedals go on easily.
Have threading standards changed, or were threads just not as accurate back in the 70s?
[update] I cleaned out the crank threads (again), put TriFlow on the MKS pedal threads and cranked them in with a sizeable pedal wrench. They didn't seem to be as happy about it as I would like, but I blew past the resistance and they threaded in all the way. Just a question of accuracy in the machining of either the cranks or the pedals I guess.