I need to find someone to finish the bores on my injector bosses or tell me how to do it.   Final i.d.should be .540 to .545 in.    The bosses are .45 in high and are bored and reamed to .5312.  Material is 6061.   I tried using a boring bar but could not maintain the tolerances.  I bought adjustable hand reamers but they were not the right tool for the job.  I considered trying to sand the bore to the correct size using a flapper but have not tried it  yet.  Suggestions?  Volunteers?     Jerry