My nephew and I are working on a small model cannon. It has a ~1" bore. We are making from a piece of A36 rod. We are having trouble clearing the chips and getting a clean bore. I don't have a reamer or a gun drill - I am looking for a one-off cheap way to get this done. At present we are using a 0.75" boring bar with a HSS cutter. Our main problem is getting a good finish. Any suggestions?