hoseman wrote:
I've seen machinists use a small block with a bunch of holes
in it where the tap would be inserted to guarantee that the
tap threads straight into the hole to be threaded. I could simply
drill a clearance hold in some scrap metal, but if I wanted to
machine such a guide,there must be some good ideas out there.
It could be a rectangular solid with a row of holes different
diameters, it could be a disk, etc. What do most people use?

I know of other techniques using the drill press chuck, a spring-
loaded tap guide, etc, but in this application, I would like a simple
guide.

Jim

This is a perennial apprentice project. Most are something like you
mention, just a block with tap-sized holes in it, pattern and variety
to suit your preferences. You probably could find any number of
designs in high school metal shop texts.

I've got one I purchased from Brownell's long ago, it's a round puck
with interchangeable bushings. The bottom has a V cut in it so the
user can easily line it up on round stock, like a barrel. It's still
for sale, but I think the current price is rather out of sight.
www.brownells.com You could bore the jig's hole so you could use
standard die bushings that can be had from the usual industrial
hardware suppliers. I use mine a lot for the smaller taps, it keeps
tap breakage down to virtually nothing. One thing I think I'd rig up
is some sort of clamp so it could be held to a workpiece. Kind of hard
juggling jig, drill and workpiece some days. These days, one or more
rare-earth tooling magnets might work, if you could find some way to
keep the chips from sticking permanently and you work mostly with
steel.

Stan