In article ,
Eric R Snow wrote:
On 23 Nov 2004 18:20:06 -0500, (DoN. Nichols)
wrote:

In article ,
Beecrofter wrote:

[ ... ]

That depends -- I sometimes sharpen down to #70 drill bits, and
would hate to try to do that by hand. For that, I have a drill grinder
made by DuMore -- the makers of the toolpost grinders. They no longer
make this, but it was available with collets for all the way down to #70
bits. Unlike most collets, these don't actually grip the drill bit
(which is gripped by a simple drill chuck), but rather stabilize the bit
nearer to the point. It will handle up to 1/4" bits.

Enjoy,
DoN.
Boy, I like that idea for grinding small drill bits. A little
stabilising sleeve or collet. Since Dumore don't make 'em any more I
think mebbe it's time to try to build my own.

If you want to see what the DuMore looks like, you might visit
this web page which I threw together when I was restoring it.

http://www2.d-and-d.com/interesting-...der/index.html

The basic mechanism is similar to a General drill grinding
fixture, except that the rotation is about a horizontal axis, instead of
the vertical axis the General uses. And -- the fixturing of the drill
bit is a lot better, including provisions for rotating it exactly 180
degrees after grinding the first flute. (There is a magnifier which
gets a view of the edge of the flute above a reference line to help you
align the flute properly for the first grind.

I managed to get a manual for this (a photocopy) from DuMore
before they stopped supplying these. Apparently, some later finders of
these machines were not able to get the manual.

Good Luck,
DoN.
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