I have picked up 2 of those General drill bit jigs that mount next to
a bench grinder, I need to know
the best setup for sharpening my own bits. Ive got plenty of area,
several motors, arbors and
many different grit wheels. I read the drill doctor uses diamond
wheels, would this be better or if
not then what size grit and speed would be best? Ive even thought of
using one on a course wheel then one mounted on a fine grit & I could
even mount the motor/wheel flat like a turntable
and grind on the wheel face instead of the side.
Anyway I would like to know the best setup sense I will be starting
from scrach & change speed
wheel type & grit, angle ect.

On 2009-01-05, wrote:
I have picked up 2 of those General drill bit jigs that mount next to
a bench grinder, I need to know
the best setup for sharpening my own bits. Ive got plenty of area,
several motors, arbors and
many different grit wheels. I read the drill doctor uses diamond
wheels, would this be better

No -- it would not -- unless you are working *purely* with
carbide drill bits. Hot diamond combines with the steel to make a
harder steel, and dull the diamonds.

or if
not then what size grit and speed would be best? Ive even thought of
using one on a course wheel then one mounted on a fine grit & I could
even mount the motor/wheel flat like a turntable
and grind on the wheel face instead of the side.
Anyway I would like to know the best setup sense I will be starting
from scrach & change speed
wheel type & grit, angle ect.

Well ... what *I* like is no longer made. Dumore made a drill
sharpener sort of like the General turned on its side, with a built in
motor and a two grit compound stone -- a narrow part for the tiny bits
and a coarser one for the larger bits. (The thing would handle bits
from #70 up through 1/4" -- but no larger than that.

The bits were held in a special drill chuck, with a collet for
each size to steady it near the tip, aligned using a mirror and a
magnifying glass to have the flute edge orientation correct, and then
the grinding was done with a lever to slide the bit over from the mirror
to the wheel, and then you press down on a thumb lever to grind one
flute, then rotate the chuck 180 degrees (built to stop at the right
point) to grind the other flute.

I *would* like it to be able to grind split points, but it
can't, and neither can the General.

The Drill Doctor can -- only for the larger bits. Smaller ones
tend to come out as disasters unless you just go for the standard
point. :-)

Good Luck,
Don.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Maybe I get a chance to offer you some advice now, DoN. I know it's my turn.

Split point drills aren't accomplished by gashing the second cut into the
back of the freshly ground cutting face.
They don't require a grinding wheel with a crisp 90 degree edge on it.

I've ground many sizes of split points by making the long ground facet at
the back of the flutes (trailing sides) first. These facets need to be equal
for both flutes.

Then the point is ground in the normal way, and the split points suddenly
appear, as if by magic.

It seems counter-intuitive, I know. I've mentioned this method here in RCM
at least several times, and not once has anyone said: hey, that does work,
so I suspect that anyone that read it assumed it wouldn't work.

What's there to lose by trying it? If anyone here doesn't have at least one
broken drill laying around, then break one and try it, or do it the next
time "someone else" breaks a drill.

It really is enjoyable to see it happen when starting with a broken drill,
because the finished drill is better than it was before it broke.

I learned this method many years ago when a friend gave me a couple handfuls
of used, quality drills with split points. When I first tried resharpening
them, I could see the points disappearing.
So then I started grinding the trailing side first, then the cutting face,
and the split points always remained prominent and sharp.

I'm sure there are optimum angles for the trailing edge grinds, but since
I've never had a Darex or other dedicated drill sharpening machine, I
eyeballed them (when the eyes were in better shape).
One industrial machine shop in a plant I worked in, had a Darex or something
similar, and grinding split points was done the same way I described, by
placing the drill holder in one hole first for the trailing grinds, then
touching up the cutting faces by putting the holder in another hole.

As far as fixturing for the trailing side facet goes, it could be a V in
front of the wheel edge, located at a low angle (that would be with the top
tipped toward the wheel from vertical) so the position of the web could be
seen when the drill is placed in the V.
The trailing side grind removes a considerable amount of material, thinning
the flutes.
Those are the two characteristics of split point drills, less flute width
and a smaller cutting face. They resemble the 4 facet grind at a glance.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"DoN. Nichols" wrote in message
...

No -- it would not -- unless you are working *purely* with
carbide drill bits. Hot diamond combines with the steel to make a
harder steel, and dull the diamonds.


Well ... what *I* like is no longer made. Dumore made a drill
sharpener sort of like the General turned on its side, with a built in
motor and a two grit compound stone -- a narrow part for the tiny bits
and a coarser one for the larger bits. (The thing would handle bits
from #70 up through 1/4" -- but no larger than that.

The bits were held in a special drill chuck, with a collet for
each size to steady it near the tip, aligned using a mirror and a
magnifying glass to have the flute edge orientation correct, and then
the grinding was done with a lever to slide the bit over from the mirror
to the wheel, and then you press down on a thumb lever to grind one
flute, then rotate the chuck 180 degrees (built to stop at the right
point) to grind the other flute.

I *would* like it to be able to grind split points, but it
can't, and neither can the General.

The Drill Doctor can -- only for the larger bits. Smaller ones
tend to come out as disasters unless you just go for the standard
point. :-)

Good Luck,
Don.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Thu, 8 Jan 2009 03:01:38 -0500, "Wild_Bill"
wrote:

snip
I don't like the little General fixture mentioned earlier, because the
little twist indexing finger isn't a good feature. That's the little pointy
adjustment located under the V (only the worst place for it).

I once ground mine away G and made a new one but I have binned it!
The destructions suggest rotating the drill until the helix is in
contact with the finger. Experience has proved that this is wrong
IMHO. When I use the General I rotate the drill until the cutting edge
is vertical by eye and clamp it there. Once the first land is ground I
leave the setting where it is and rotate the drill until the second
land is again vertical
The little General fixture makes a great relief grind as it swings, but it
will make it anywhere on the end of the drill. So ya play and adjust and try
a few grinds, then play and adjust some more until it's leaving the
narrowest chisel point, but ya start over as soon as you try another size
drill.

The destructions are reasonably valid with regard to overhang etc but
you do need to adjust the jig in and out as you note below.

Besides that problem, the only sensible way to mount the General fixture is
on a slide or a mount that allows it to be moved toward/away from the
grinding wheel and held in place. Bolting it to a fixed point as suggested
in the instruction sheet, sucks.

My fixture has a slotted base!
smip

One other point, the grinding position as shown in the instructions is
non preferred IMHO. Better to grind on the wheel face above or below
the spindle. That way the grind is perpendicular to the edge.

I must say I rarely use my jig.
1 I can grind by hand adequately
2 My drills last a long time primarily because I load them and keep
them cutting. A colleague once said when he saw me drilling some steel
with a hand power drill "you don't drill holes you punch them".
Interesting that my drills were never changed or sharpened but his
were always needing replacing G
Richard

On Jan 8, 3:01*am, "Wild_Bill" wrote:
...
Some Drill Doctor owners will probably argue that, but I've read the
complaints of many stating it works OK some of the time, on certain sizes..

I don't like the little General fixture mentioned earlier, because the
little twist indexing finger isn't a good feature. That's the little pointy
adjustment located under the V (only the worst place for it).
The little General fixture makes a great relief grind as it swings, but it
will make it anywhere on the end of the drill. So ya play and adjust and try
a few grinds, then play and adjust some more until it's leaving the
narrowest chisel point, but ya start over as soon as you try another size
drill.
Besides that problem, the only sensible way to mount the General fixture is
on a slide or a mount that allows it to be moved toward/away from the
grinding wheel and held in place. Bolting it to a fixed point as suggested
in the instruction sheet, sucks.
...
If the fixed point on the General fixture was on top where it could be
adjusted easily, that would be tits.

Looking at a General No. 825 from the 60's, if the pivot for the hold-
down clamp was moved further outward to reduce its angular rotation, a
'billet' clamp could include a top finger. Unlike the bottom one the
contact point would shift lengthwise with drill diameter.

The original Drill Doctor works well enough for me, but I've also been
considering putting the General fixture on the surface grinder to use
its XYZ motion, and making a sleeve that fits onto Darex chucks with
an alignment wire or plate across the end.

With a conventional grind on a drill, maintaining the narrowest chisel point
(at the web) is the key to having a drill that cuts and feeds easily, and a
drill that may only rub a hole in something if enough pressure can be put on
it.

I use a small parabolic drill first to avoid fussing with split
points.

I've pondered how to make a round drill holder resembling a drill chuck for
quite a while, and haven't come up with anything better than modifying a
drill chuck. Snugging the chuck jaws against the drill flutes could cause
chipping, so gripping the shank would likely be a better approach.
Supporting the drill near the point presents another challenge, since
bushings for every drill size would be problematic as far as time consuming
to make and/or expensive to buy. Something like a camera lens iris might be
a possibility.
WB

Bison makes 6 jaw chucks for tool grinding. Not Cheap!!
http://brassandtool.com/Chucks-Lathe.html

The Darex chucks aren't bad as long as you don't tighten them more
than necessary.

I made this 5C collet nut for sharpening large drill bits in an end
mill grinding fixtu

http://picasaweb.google.com/KB1DAL/T...98039281271986

The 1/2" insert centers S&D drills by the shank. The back relief
setting grinds a 120 degree point. A long bit will clear the side of
the mag chuck while the base is on the poles. I've been downstairs
trying it and clearly need to make a spanner wrench to tighten the
collets more.

Jim Wilkins

The General-type drill fixtures I've got have a slotted base too, Richard,
but loosening the nut/bolt will allow the base to rotate, so that's just
more futzing around with adjustments.

I agree with your comments regarding the instructions, like many instruction
sheets, they didn't get it right.

And like many little handy helper devices, just a little more design work
would've made a great little drill grinding fixture that almost anyone could
set up and get very good results with very little effort.

Very good lighting, properly placed near the work area is a requirement for
sharpening by hand. I used to be quite good at it, but now even with 3 or 5
diopter magnifying lenses, the results aren't as good as when I was using my
20 year old eyes.
This is where a fixture that indexes to the twist, and has two locations 180
degrees apart would greatly simplify resharpening, without even seeing the
drill point.

I also agree with your comment regarding agressive feed rates and grinding
on the wheel face, not the side. When a drill is sharpened properly, there
is no reason not to push the feed, using a good cutting lubricant.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Richard Edwards" wrote in message
...
On Thu, 8 Jan 2009 03:01:38 -0500, "Wild_Bill"
wrote:

snip
I don't like the little General fixture mentioned earlier, because the
little twist indexing finger isn't a good feature. That's the little
pointy
adjustment located under the V (only the worst place for it).

I once ground mine away G and made a new one but I have binned it!
The destructions suggest rotating the drill until the helix is in
contact with the finger. Experience has proved that this is wrong
IMHO. When I use the General I rotate the drill until the cutting edge
is vertical by eye and clamp it there. Once the first land is ground I
leave the setting where it is and rotate the drill until the second
land is again vertical
The little General fixture makes a great relief grind as it swings, but it
will make it anywhere on the end of the drill. So ya play and adjust and
try
a few grinds, then play and adjust some more until it's leaving the
narrowest chisel point, but ya start over as soon as you try another size
drill.

The destructions are reasonably valid with regard to overhang etc but
you do need to adjust the jig in and out as you note below.

Besides that problem, the only sensible way to mount the General fixture
is
on a slide or a mount that allows it to be moved toward/away from the
grinding wheel and held in place. Bolting it to a fixed point as suggested
in the instruction sheet, sucks.

My fixture has a slotted base!
smip

One other point, the grinding position as shown in the instructions is
non preferred IMHO. Better to grind on the wheel face above or below
the spindle. That way the grind is perpendicular to the edge.

I must say I rarely use my jig.
1 I can grind by hand adequately
2 My drills last a long time primarily because I load them and keep
them cutting. A colleague once said when he saw me drilling some steel
with a hand power drill "you don't drill holes you punch them".
Interesting that my drills were never changed or sharpened but his
were always needing replacing G
Richard

Nice job on adapting the endmill grinding fixture, Jim.

For others that might be following along, the General-type fixture has been
available for decades, and one of mine is a Craftsman, but they're still
being made.. and copied, presumably in China sweatshops for the tool
importers

http://www.drillspot.com/products/57...ner_Attachment

Those Bison chuck prices range from almost $100 to over $100 per inch..
ouch, that's just extravagance for a hobbiest.

Your modification recommendation for the clamp on the General fixture would
be a very good addition.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Jim Wilkins" wrote in message
...
...
If the fixed point on the General fixture was on top where it could be
adjusted easily, that would be tits.

Looking at a General No. 825 from the 60's, if the pivot for the hold-
down clamp was moved further outward to reduce its angular rotation, a
'billet' clamp could include a top finger. Unlike the bottom one the
contact point would shift lengthwise with drill diameter.

The original Drill Doctor works well enough for me, but I've also been
considering putting the General fixture on the surface grinder to use
its XYZ motion, and making a sleeve that fits onto Darex chucks with
an alignment wire or plate across the end.

With a conventional grind on a drill, maintaining the narrowest chisel
point
(at the web) is the key to having a drill that cuts and feeds easily, and
a
drill that may only rub a hole in something if enough pressure can be put
on
it.

I use a small parabolic drill first to avoid fussing with split
points.

I've pondered how to make a round drill holder resembling a drill chuck
for
quite a while,

Bison makes 6 jaw chucks for tool grinding. Not Cheap!!
http://brassandtool.com/Chucks-Lathe.html

The Darex chucks aren't bad as long as you don't tighten them more
than necessary.

I made this 5C collet nut for sharpening large drill bits in an end
mill grinding fixtu

http://picasaweb.google.com/KB1DAL/T...98039281271986

The 1/2" insert centers S&D drills by the shank. The back relief
setting grinds a 120 degree point. A long bit will clear the side of
the mag chuck while the base is on the poles. I've been downstairs
trying it and clearly need to make a spanner wrench to tighten the
collets more.

Jim Wilkins

On Thu, 08 Jan 2009 10:24:18 +0000, Richard Edwards
wrote:

On Thu, 8 Jan 2009 03:01:38 -0500, "Wild_Bill"
wrote:

snip
I don't like the little General fixture mentioned earlier, because the
little twist indexing finger isn't a good feature. That's the little pointy
adjustment located under the V (only the worst place for it).

I once ground mine away G and made a new one but I have binned it!
The destructions suggest rotating the drill until the helix is in
contact with the finger. Experience has proved that this is wrong
IMHO. When I use the General I rotate the drill until the cutting edge
is vertical by eye and clamp it there. Once the first land is ground I
leave the setting where it is and rotate the drill until the second
land is again vertical
The little General fixture makes a great relief grind as it swings, but it
will make it anywhere on the end of the drill. So ya play and adjust and try
a few grinds, then play and adjust some more until it's leaving the
narrowest chisel point, but ya start over as soon as you try another size
drill.

The destructions are reasonably valid with regard to overhang etc but
you do need to adjust the jig in and out as you note below.

Besides that problem, the only sensible way to mount the General fixture is
on a slide or a mount that allows it to be moved toward/away from the
grinding wheel and held in place. Bolting it to a fixed point as suggested
in the instruction sheet, sucks.

My fixture has a slotted base!
smip

One other point, the grinding position as shown in the instructions is
non preferred IMHO. Better to grind on the wheel face above or below
the spindle. That way the grind is perpendicular to the edge.

I must say I rarely use my jig.
1 I can grind by hand adequately
2 My drills last a long time primarily because I load them and keep
them cutting. A colleague once said when he saw me drilling some steel
with a hand power drill "you don't drill holes you punch them".
Interesting that my drills were never changed or sharpened but his
were always needing replacing G
Richard
I have a couple of these "General" fixtures and have been thinking of
setting one up in conjunction with my 4 1/2" angle grinder as a
roughing sharpener then finishing on my Drill Doctor. Somewhere in
connection with this group I have seen picture of an adjustable mount
for the "General" fixture where it is moved on round rod ways by means
of a lead screw arrangement.
Gerry :-)}
London, Canada

On Thu, 8 Jan 2009 03:09:26 -0500, "Wild_Bill"
wrote:

That's what I've read repeatedly, Gerry. Various little problems, but
overall, a somewhat useable machine.
But if it only sharpens some sizes consistenly, that reduces the number of
different fastener sizes that one needs to buy.
I suspect that some of the problems are a result of too much plastic being
used to make them.
I have used mine to sharpen drills from 3/32 up to 3/4" with fully
satisfactory results. It's just the point splitting that bothers me.
Gerry :-)}
London, Canada