You need to index the studs your using . Meaning, Put them in where they will be, Tighten them up and mark the stud at the feed hole so when installed they line up with with the groove cut in the stud. Install yours , Mark them , And then send them to me or take them to a local machine shop. The groove is cut in the stud with a ball mill. We won't charge you anything to face 2 studs. Just the shipping. SK Machine, Danielsville Pa.