I am in the process of changing my pedals from old Shimano Deore to something with a standard thread. The Deore pedals are 1"-24 and the new pedals are 9/16"-20 so there is enough room to make thread insert adapters. I work at a machine shop so I could make them myself, but by the time I get the material and then send them out for coating to resist corrosion I'm sure it would be cheaper to buy them. Does anybody know if there's a company out there that makes an adapter like this?

The torque applied at the pedal's axle is so great and frequent that I would personally do no such thing. You may want to get a second opinion in the mechanics section though.

I've seen these discussed here before. Adapters are (were) available but were typically in the $50 range. Most suggested changin the cranks as a better option as there was some concern about the material being thin at the end of the crank arm and having a likelyhood of cracking.

Mechanics section it is. Thanks