On 01/17/2018 06:58 PM, Bob La Londe wrote:
I started free hand grinding my own drill bits a few months ago.Â* Not
out of choice, but out of necessity.Â* Since I started doing it I have
reground a fair number of them.Â* Sometimes the same one two or three
times in the same set of jobs.Â* Now I have old eyes, but my glasses are
pretty good, and I have a magnifier lamp I swing over my bench grinder.
It allows me to free hand better than I ever thought I would be able to.

I've also resharpened some of my stub length Silver and Deming bits.
That's where it really pays off.Â* I bought a set of those some years
back, but I've never seen them available singly.Â* The 5/8 took quite a
beating over the years since its the standard injection port size for
hand injecting plastisol.Â* I actually make injectors .620 and sprues
.63, but sometimes you just have to brute force a solution.Â* It was nice
to finally be able to just sharpen it right up.

No more piles of drill bits to be sharpened someday.Â* I just sharpen it
right up and drop it back in its spot.Â* Which brings me to the other
size limit.

The smallest I've reground so far was a #21.Â* I picked that one to push
the smaller size limit because I have several of them on hand.Â* I
ordered a half dozen of them once from McMaster in stub screw machine
length to drill molds for 10-32 clamping screws.Â* It came out ok.Â* I'm
not sure how much smaller I could grind free hand.Â* Probably not much. I
was squinting a bit at it and gritting my teeth.Â* LOL.Â* So how small of
drill bits do you free hand regrind.Â* I don't have a drill doctor or a
Darex or a knockoff.Â* Just a bench grinder.Â* Well a couple of them and a
small belt grinder now.

I think one of the limits is grit size, but another would be heat.Â* It
would be really easy to overheat a tiny little drill bit.

I got a Drill Doctor at a metal club swap meet a few years ago. If you
follow the directions, they work pretty well.

I think the lower limit on them is 3/16" or maybe 1/8"

My attempts at free-handing a drill bit were disappointing at best.

BobH