I have one of those drill bit sharpener stands thats suppose to be
used with a bench grinder,
the problem is it dosent say where to mount it, do you grind the bit on
the side or the face of
the grinding wheel? Im going to setup a grinder just for this purpose
so is there a proper grit or type wheel for resharpening dull bits? I
also have a choise of motor RPMs i can use.
Sounds like alot of questions but i either use the stuff i have on
hand or buy a drill doctor 750 so im gonna try the stand/grinder setup
first.

wrote in message
ups.com...
I have one of those drill bit sharpener stands thats suppose to be
used with a bench grinder,
the problem is it dosent say where to mount it, do you grind the bit on
the side or the face of
the grinding wheel? Im going to setup a grinder just for this purpose
so is there a proper grit or type wheel for resharpening dull bits? I
also have a choise of motor RPMs i can use.
Sounds like alot of questions but i either use the stuff i have on
hand or buy a drill doctor 750 so im gonna try the stand/grinder setup
first.

I'm assuming you mean a "General Drill Grinder" type fixture. The bit sits
in a V pocket, you clamp it in with a bolt you tighten and rotate the front
cutting edge against a stop. This idea goes from an extremely well made
grinder with a 12" wheel to the "General Drill Grinder" fixture that costs
less than $20. "You gets what you pays for."

I played with one of these el cheapo units a lot years ago. It is possible
to grind good bits with one but a total PITA. They won't work on the face of
a small grinder, you get a curved drill point. So you have to use the side -
big big NO NO for safety. The distance that jig sits from the wheel surface
has a HUGE impact on drill geometry and the proper distance increases with
increasing drill size. clamping to a table won't get it - you need this a
some sort of table with a screw adjustment.

The concept is solid - I built a unit for drill bits up to 2" that sits in
my tool and cutter grinder. I can grind an absolutely perfect drill point on
a huge drill bit.

Within the last couple days, I reposted TEENUT's how to grind a drill bit.
Its the best ever tutorial on how to sharpen a drill bit. Must reading.

Karl

On Sun, 15 Jan 2006 01:01:44 -0500, "Karl Townsend"
remove .NOT wrote:


wrote in message
oups.com...
I have one of those drill bit sharpener stands thats suppose to be
used with a bench grinder,
the problem is it dosent say where to mount it, do you grind the bit on
the side or the face of
the grinding wheel? Im going to setup a grinder just for this purpose
so is there a proper grit or type wheel for resharpening dull bits? I
also have a choise of motor RPMs i can use.
Sounds like alot of questions but i either use the stuff i have on
hand or buy a drill doctor 750 so im gonna try the stand/grinder setup
first.


Comments by Karl Townsend snipped to conserve space

Take a look at this picture

http://neme-s.org/NEMES_2005/NEMES_2005_16.htm

It shows a set up created by Gene Martha of NEMES that works quite
nicely and permits adjustment of the tool as Karl mentioned.




Errol Groff

Instructor, Manufacturing Technology
H.H. Ellis Technical High School
613 Upper Maple Street
Danielson, CT 06239

New England Model Engineering Society
www.neme-s.org

Great photo, it says it all but both Karl and your photo indicate the
distance to the wheel makes a big difference? Im can make a sliding
rig like that but still cant reason why the distance to the wheel has
any effect?

It sound like you have one of the old General Drill Sharpening fixtures.

Learned to sharpen drills free had back in HS shop and still do most of the
time. However, someone gave me a complete General a few years ago and I
never did anything with it since I didn't have a grinder with room on the
left side of the fine wheel, where it was suppose to be installed.

As I got more into machining and got a drill press with low rpm for larger
bits, I found I needed a fixture to better sharpen the larger Morse taper
and Silver Deming drill bits.

I didn't have the instruction sheet for installation and operation of the
General, so I went to the hardware store where they still had them for sale.
I pulled the instruction sheet out of the box and ask for a copy. That done
I installed it and found it a PITA to get set for each drill, especially if
the were of significantly different sizes. I finally accumulated enough
redundancy in drills that I could switch drills and put the dull ones in the
box and sharpen them when I had enough to make it worth my time to adjust
the settings as I changed from small to larger sizes.

I think I finally found a web site that also had the instruction posted on
it. I don't have the link anymore but I might be able to find the copy I
have of the instructions.

One thing that bothers me about this General sharpener, is the fact your are
grinding on the side of a wheel that is not intended for this. This goes
against all the Safe Shop Practices that I have lived with for 50+ years.
(well most of the time and if I ignore SSP, I always stand to the side at
arms length with an face shield, etc.) Back to my point. I have always been
taught and have taught, never grind on the side of a grinder wheel that
isn't designed for that purpose. It under cuts the wheel and could cause it
to explode when grinding on the rim, as intended. My be I'm preaching to the
preachers.

One thing about grinding on the side with the General fixture, you are
standing to the side of the wheel.

Bottom line, I can still free hand sharpen bit below 3/8 better and easier
than with the General fixture. From 3/8 to 3/4s it's a toss up. For the big
ones the General gives a better center and angles than I get from free hand.

IMHO, the General or similar fixtures, a 8" wheel would be my minimum, but
that is based on the fact, I just don't like to do any grinding work in the
smaller wheels. I also like at least a 1" or greater width. Not many home
shop grinder have the shaft length and guards for the thicker wheels. I had
to modify my HF 8" grinder to take my large stock of 1" wheels.


--
My experience and opinion, FWIW

Steve

I too would like to see some pictures of how others have set up a
grinder station that includes sharpening.

Many times it sounds like others just slap the grinder on the first
flat surface they come across and have at it. Considering grinding dust
is ABRASIVE and a machine shop is supposedly concerned with accurate
work on expensive machines, I would expect the placement, setup and
usage of a grinding setup for drill sharpening would take some
planning.

TMT

Karl Townsend wrote:

wrote in message
ups.com...

I have one of those drill bit sharpener stands thats suppose to be
used with a bench grinder,
the problem is it dosent say where to mount it, do you grind the bit on
the side or the face of
the grinding wheel? Im going to setup a grinder just for this purpose
so is there a proper grit or type wheel for resharpening dull bits? I
also have a choise of motor RPMs i can use.
Sounds like alot of questions but i either use the stuff i have on
hand or buy a drill doctor 750 so im gonna try the stand/grinder setup
first.


I'm assuming you mean a "General Drill Grinder" type fixture. The bit sits
in a V pocket, you clamp it in with a bolt you tighten and rotate the front
cutting edge against a stop. This idea goes from an extremely well made
grinder with a 12" wheel to the "General Drill Grinder" fixture that costs
less than $20. "You gets what you pays for."

I played with one of these el cheapo units a lot years ago. It is possible
to grind good bits with one but a total PITA. They won't work on the face of
a small grinder, you get a curved drill point. So you have to use the side -
big big NO NO for safety. The distance that jig sits from the wheel surface
has a HUGE impact on drill geometry and the proper distance increases with
increasing drill size. clamping to a table won't get it - you need this a
some sort of table with a screw adjustment.

The concept is solid - I built a unit for drill bits up to 2" that sits in
my tool and cutter grinder. I can grind an absolutely perfect drill point on
a huge drill bit.

Within the last couple days, I reposted TEENUT's how to grind a drill bit.
Its the best ever tutorial on how to sharpen a drill bit. Must reading.

Karl



The General drill grinding devices are intended to grind on the SIDE of
the wheel, using a **SPECIAL** wheel that General sells for the purpose.
One should **NOT** try to grind on the side of a regular grinding wheel!
.... It's DANGEROUS!

Alternatively to the General wheel, one could us a steel backed Al-Ox
'plate' wheel (as used on 'carbide' grinders). A special arbor and
flange would be needed to mount one of these on a standard grinder.

Or, if you have a carbide grinder, you could use that. Just remove one
table from the grinder, and mount the General attachment.

The General jig does work fairly well once you learn to use it, but
they're no substitute for a proper drill grinder like a Darex or Black
Diamond.

Dan Mitchell
============