I'm mounting a set of rails in the bed of my 3/4 ton truck for a
removable goose neck or fifth wheel hitch. Either or. My dad was
giving me a hand today, and I got to the point of drilling the frame
holes to size (17/32). I had a grand total of 1 17/32 drill and last
night it had a MT2 taper and maybe a 7/16 pilot point. My son and I
drilled the bed holes with it last night after turning off the Morse
taper. (made me cry a little bit) Today drilling the frame the pilot
point followed the 3/16 pilot hole just fine, but the shoulder out to
17/32 was taking forever.
I didn't see any easy way to sharpen that little shoulder so I just cut
the pilot point off with a zip disc and reshaped the end of the drill
free hand on the grinder. When it went through the next six holes in
half the time as any of the previous holes I said, "Golly, if I had one
of those fancy drill doctors I bet I could make it almost as sharp and
drill nearly as fast." My dad didn't say anything. He uses a Drill
Doctor to sharpen drill bits.
Its kinda funny. Some of you guys might remember when I didn't have a
clue how to sharpen a drill bit. Now I'm kinda being an ass about it.
...I got to the point of drilling the frame holes to size (17/32). ...
When I need a custom diameter or taper hole I make a D bit. They won't start
a hole and cut slowly, so remove what you can with a twist bit. The tapered
ones are for air or fluid nozzles. When I can't measure the recess I want to
copy I press polymer clay into it and heat-set it to make a template.
Turn the hole and max drill chuck diameters on drill rod, and point it like
a twist drill, the angle isn't critical and the center point is only a
sharpening guide. D bits aren't aggressive enough to need 3 chucking flats
on the shank if it's smaller than the hole size.
I normally make them short like countersinks, to save drill rod and avoid
needing a tailstock center hole, and cut whatever angle my HSS lathe bits
were sharpened at, without resetting the compound. Unless it will fit a
collet block, mill the cutting end just shy of half-round before parting
Smear on Ivory soap, heat red hot until non-magnetic and quench in oil.
Water may work on small ones. The soap reduces oxidation. There are many
other recipes, some of which carburize or nitride or both.
Grind the flat shiny and heat to yellow to temper.
Grind the flat down to the center to create the cutting edge. They still
work if ground beyond the center.
Try it. If it dulls, reharden and temper to a lighter yellow. If it chips,
temper darker and regrind. Grinding some relief behind the cutting edge may
help them cut faster with less pressure. I needed several hardening tries to
make one drill a truck leaf spring for a lift kit's larger U bolts.
A variant that cuts faster but rougher is the spade bit.