Do not recommend for prototype custom machining... I took in ATV parts that had a worn out hole in them to have them bushed from 5/8 to 7/8 to tighten up the hole. They made the 7/8 with lots of clearance so I had the same condition just a bigger diameter and the owner told me itll still clamp and he didnt seem to understand that it needed to be a precision fit thats why I brought it to him to be repaired...they broke one of them and told me Im sorry, but it was already wore out when you brought it so youre not getting your money back and were not paying for the replacement... I got screwed, I paid them $200 for repairs and now I got to pay $400 for a replacement part that could have been fixed if they knew what they were doing...