I have access to a Kuhn KB1  hammer. It is set up with a 3 phase motor. I want to swap out the motor for a single phase one. What other problems should I anticipate? I understand I may need need a new Mag Starter. Anything else for me to worry about? Thanks.

Also, are parts still available for the KB1

A three phase starter will work with a single phase motor. You just leave one leg open.

They make VFDs that are  single phase input and 3 phase output, you can buy them on ebay for 100 bucks, i use one on my drill press and belt grinder. 

ive done it twice on the Kuhn clones, (Sahinler) once was a 60KG i swapped out to single phase 7,5hp motor no issues and just a couple months back a 50KG sahinler with a 5hp single phase motor. no problems. its pretty straightforward 

 

before she was powered up but its simple, just getting a pulley right size or adapting it to the new motor takes some figuring