Fig. A: Thread a nut on the bolt, put it in a vise, and cut
off the head with a hacksaw. Fig. B: Clean up the bolt
shank and head with a file or sandpaper.
Fig. C: Use a center drill on the shank of the bolt to
prevent the twist drill from “walking.” Fig. D: Hollow
the shank of the bolt with a
2" twist drill.
½- 13× 2" SAE Grade 1 or 2 steel bolt
Nut to fit bolt
Small O-ring or rubber seal (optional)
1. BEHEAD THE BOLT.
Begin by cutting off the head of the bolt with a hacksaw on a bench vise (Figure A), and then cleaning
up the shank and the head with either a file or a belt
sander (Figure B). The jaws of a vise will crush the
threads of the bolt, so hold the bolt by a nut that is
run all the way up the shank.
Photography by Brian Dereu
File or belt sander
Drill press with vise
Center drill bit
2" twist drill
j" drill bit
½- 20 thread, high-speed steel tap and die
Small, tapered center rod or steel rod
to grind your own
2. HOLLOW THE SHANK.
Transfer the bolt shank to a drill press vise and
adjust it to bring the spindle of the chuck directly
atop the center of the shank. When drilling steel, it’s
always advisable to start the hole with a center drill
to keep the twist drill from “walking” (Figure C).
After center drilling, drill the cavity hole in the
shank with a
2" twist drill to a depth of 1½" or so.
Use plenty of cutting oil, and peck the drill up and
down often to clean out the chips and to introduce
fresh coolant into the hole (Figure D). Chamfer the
hole with a countersink bit.