It can be done fairly cheap. All you need is a drill press, a machineist vice and indexing fixture. I did a couple of then using this methos and they turned out great. For polishing the I used valve grinding compound and 3/8 inch round felt tips that could be screwed onto the shaft that was chucked into the drill. You can get a fixture from Brownell or Midway.
If you plan to do this, I advise you to do a little experimenting on something before starting on the bolts. As as stated above, it takes time to do a good job, but it also takes practice.