On Tue, 07 Jun 2011 00:07:07 -0500, Ignoramus21994
wrote:

I just wanted to hear, from Karl or someone else. How hard was it to
learn to grind drill point freehand, on a tool grinder or a bench
grinder?

Depending upon your dexterity, it can take very little time, Ig. My
dad showed me when I was 7 or so. I watched him do it, and he
explained as he went. He gave me a large bit to try on. I bought very
few new bits when I wrenched for a living. People would give me their
broken or dull bits and I'd fix them for myself.


Was it easy to find out when you would make a mistake?

Three mistakes show up clearly. First, you push too hard on one side
and the point is then visibly off-center. Second is if you get the
angle wrong and it just won't cut anything tougher than butter.

The method I use, which is probably typical:

1)Don goggles and gloves. Bits get hot, so have a cup of water nearby.

2) Start the grinder, belt sander, or disc sander. On a grinder, I
usually grind bits softly, so I use the side of the wheel. (Luckily,
one has never exploded on me.) It's usually quite a bit smoother and
some guides aren't easily removable. You need space for your fingers
near the wheel. A 120 or smoother grit belt works wonderfully, too.

3)Hold the bit in your fingers at an angle which makes the cutting
surface of one flute parallel with the wheel surface, with the cutting
edge (lip) facing upward. (59 degrees for standard 118 degree bits)
Now touch the lip to the wheel until it is sparking evenly. As it
touches, push in lightly lifting the tip of the bit upward, making the
grind progress along the cutting face of the flute. (Alternatively,
you can rotate the bit through that arc.) You want the back of the
flute land to be about 15 degrees lower than the cutting edge. The
grinding part should take less than a second to do for each flute. Do
one side, rotate the bit 180 degrees, and do the other side. Now dip
it in water and look at it/feel it. Is it sharp, centered, and have
the relief you need for drilling? Good, you're done.

See? That wasn't hard.


--
Experience is a good teacher, but she send in terrific bills.
-- Minna Thomas Antrim