wright1902glider wrote:
Hello everyone,

I'm back in the shop again with a new problem. That is, how to drill
accurate holes on-center through steel tubing.

I need to attach 2 short lengths of 1/2" EMT tubing parallel to the top
tube of a bicycle frame, one on each side. The EMT tubes will extend
about 20" forward of the bike frame. The frame tube is about 1" dia. I
want to drill horizontally through all 3 tubes and attach everything
with a pair of #10 machine screws.

Prob. is how to drill the holes on center so everything lines up. I
have both a drill press and cordless drills at my disposal.

Suggestions? Methods? Tools?

Thanx,
Harry
Wright Brothers Bike Guru
Wright 1902 glider
Wright 1899 kite


Harbor Freight has a jig for about $5. Just a V-shaped piece of
aluminum that bolts to the bench press table. Position it so that the
bit drops down into the bottom of the V. Center punch the tube, and
position the tube on the jig so that the bit drops to the punch
depression. You'll get a centered hole every time.

I build my own jig from a piece of steel angle and a couple of bolts
before I realized that Harbor Freight sold the jig.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."