One of the things that our team is going to focus on this year is precision in getting holes in our aluminum tubing – getting the right size hole into exactly the right place on the tube. And, no, we do not have a mill or a CNC router.
Step one for us was replacing our old 8" Harbor Freight drill press. It has a number of problems that hurt the precision: first, the runout is just horrible, which means that holes are either oversize or (more frequently) just not in the right place. Second, the table isn’t exactly square with the upright, making it hard to drill parallel holes. Third, the table just clamps on to the upright – there is nothing preventing the table from moving side-to-side when you only want to move it vertically. (So, “Ok, drop the table to move to a larger bit, then raise it back up” is a lot harder than it should be.)
Step two is clamping: We started using a drill press vise last season (as opposed to just clamping material to the table), and it really helped keep the work in place.
Step three, I think, is technique: shallow holes should use short drill bits, and the table should be as close as possible to the retracted spindle. Since distance magnifies runout, this will reduce the amount of runout that’s there. Is this right?
And, what else am I missing? How do we measure and mark precisely so we are putting holes in the correct place? Do we get a sliding vise? (The cheap ones don’t seem to be all that precise and the expensive ones are, well, expensive. ) Should we get a center finder (like what milling machines use)?