My 4 inch one came with a chuck adapter, threaded fo the Myford spindle, but I have not tried it out yet. RDG are an excellent company, great value, and everything I have ordered has arrived the next day. The Royal Enfield you are waiting for, is it an original or one of the Indian ones, I believe they are a very good bike, and now comply with current emission regulations. The one I saw even had an electric start. Your engine is coming along nicely, you will soon have it up and running, nice work. I like the idea of salvaging stainless rod out of old HDD's, I have a few kicking about so I will investigate.....