I found this good explanation of sharpening tiny drills on a
machining web site. Sounds interesting, and thought I’d shaRe:
I had to drill 1428 holes @.022 diameter in some Brass sheet. I
found, that even with a Dumore Sensitive drill (17 K) I was breaking
drills after 2 to 3 holes. I tried 3 different brands and by the
time I reached 25 holes, I thought I was going to go nuts, These were
brand new drills… and all failed. So I resharpened them by hand
without any special equipment. My first drill went 25 holes…I was
on to something. My Drill times were easily cut in half (or better)
and I got 100 holes per drill. I personally think the factory micro
drills are not sharpened properly ! No tooling other than a pin
chuck!
To sharpen: Get your self a small stone (1/4 x 1 x 3), like a
Arkansas or medium fine India. Also get a pin chuck. Mine was from a
hobby shop, made by Xacto, that will clamp down to.000 Take the chuck
head, which is the size of a pencil end, and mark two side with red
paint at 180 degrees from each other. Put the drill in the chuck and
draw it perpendicular accross the stone 3 times. Inspect the results
with a 10 power glass, You should see a perfectly flat bottom drill.
Have you ever seen a Left handed person write with a pencil. They
sort of curve their hand so the pencil hooks back towards their
wrist! Thats what you wan! But first, while you have the mag glass in
your hand, loosen the pin chuck and rotate the drill bit, so the
flute lines up with the paint mark. That way, you DO NOT need to use
a glass while sharpening.
Set the stone in front of you…straight outwards, on the bench. Rest
your hand on the bench,while holding the pinchuck like a Lefty (
backhanded)! so the drill point is aimed at you mostly. BUT in your
right hand ! Make sure the paint mark is at 90…towards your
wrist…sideways.
Now set your pinky finger against the side of the stone, and draw
the cocked drill accross the stone towards You about 1 to 2 inches.
Try a 45 degree angle in X and Y to start with to see results! Use
Light pressure! Use your pinky as a guide, so when you return your
stoke back, all relationships stay the same. Do not flex your hand
and make only 3 strokes (!) Now without twisting or moving your
hand,spin the drill chuck (roll ?) so the other paint mark comes
into the same position, and stroke 3 times.
If you had the drill inclined with the point towards You( !) and
angled sideways, you will have a perfectly sharpened drill bit. The
toughest part, is setting the flute to the paint mark, as you may
find you are off target.
You will quickly see what angle to grind/ hold your hand, and
believe it or not, the grind is very symetrical. I saw spiral chips
I know this all sounds complicated, but I tried to explain for
someone to follow. Try it guys…you will be amazed…guaranteed !.
and best of all, it takes only a few seconds to do, once you
understand how to hold your hand, while drawing it accross the
stone. No rollers, no fixtures, and no tooling other than a pin chuck!