I'm switching out the cottered Magistrioni crankset on my early 60's Ideor for an early 70's Nuovo Record crankset. I was planning on using the Sheffield pedals that came on the bike with the new crankset but I read somewhere that early pedals designed for steel cottered cranksets may not have long enough threads to work properly on newer aluminum cotterless cranksets. Anyone have any opinions? Is it okay to use the Sheffield pedals or should I get more modern pedals designed to be used on an aluminum cotterless crankset? Thanks for any information.

Why should there be any problem? The contact with the crank is chromed steel threading into an aluminum threaded hole, same as with a Campy pedal, Suntour pedal, or modern clipless pedal. I think the Sheffield should be just fine. But make sure you clean the threads, and use lube or antisieze to assemble it. If the chrome is not solid, or if I'm wrong about the Sheffields having chrome, there will be some protection against siezure.

Road Fan

like he said, he's concerned cuz the threads are shorter than on pedals of later vintage.

i've never had a problem in this situation

remember, the earliest alloy campy cranks had the pedal hole dustcaps and were designed to be used with these same early short-thread pedals

I wouldn't worry about safety at all. It may look odd that the threads will be short but it won't affect the function of the pedal. Also, take some pictures, Sheffield are probably my favorite pedal.