I have one of those 5C endmill sharpening fixtures used to sharpen the
ends of endmills. Its a vertical thingy to hold the endmill, with a
couple angles machined into the base of the unit.

How the heck do you use one? Ive found cartoon type generic
illistrations on the net..but were pretty vague. Ive got a bunch of
nicked up end mills that I could clean up on the surface grinder if I
knew how.


Gunner, who can bearly sharpen a drill bit on a belt sander

"To be civilized is to restrain the ability to commit mayhem.
To be incapable of committing mayhem is not the mark of the civilized,
merely the domesticated." - Trefor Thomas

First, make sure you got a stone for sharpening HSS - Borazon is best or
soft friable grade pink stone. Or if you're doing Carbide about the only
thing I've had luck with is a diamond wheel - the green one are supposed to
work though.

For your first few, use a larger cheap HSS endmill that doesn't need a lot
removed. The bottom of your fixture has two flats.One flat gives maybe 20
degree relief for the secondary relief. The other flat gives maybe 4 degrees
relief for the primary relief right at the cutting edge. The unit has little
ball detents so you can easily rotate the endmill exactly 1/2, 1/3, 1/4, 1/6
of a turn.

This is hard to explain, easy to show. Tighten the endmill and collet in the
holder so the cutting edge goes straight across. Then place the unit in the
surface grinder so it grinds on just one flute. 1/2 the endmill is under the
stone and one flute is coming up right along side the stone. This has to be
CLOSE but not touch. Too far way and you'll end up with a tit in the center
of your endmill after you're done. Too close, you'll sharpen the leading
edge off the next flute with the side of the wheel.

Once you're set up slowly lower the wheel and grind off a bit on one flute,
back and forth. Then rotate the endmill to the next tooth and grind it.
(there are twelve detents on mine, so 6 clicks is 1/2 turn, 3 clicks is 1/4
turn etc etc) Go all the way around, lower the wheel and repeat. On a very
slightly dulled EM you can do only a few licks on the primary relief. On a
bad one, I do the secondary relief first, then finish with primary.There's
specs on the amount of primary relief, but just look at it - the land on the
endmill should be the same as a new one. On a REALLY bad one, get the
endmill close by hand in a bench grinder first and save some time.

This will give you an endmill that's not center cutting, and has no
"fishtail". But works real good for most applications. For center cutting,
you'll have to learn to gash the endmill first. I do this by hand with a die
grinder and cutoff wheel under a 10X magnify light. For "fishtail" (center
of endmill relief from edge), you can set the fixture on the surface grinder
at a 30 degree angle, but with the endmill itself square to the wheel.
(Again - easy to show; hard to explain)

This will take some playing to learn. Spend a day or two screwing up. After
you get on to it, it only take a few minutes to sharpen the ends.

Good Luck

Karl

OK! So howzabout doing the flutes on those same endmills?

Bob Swinney
"Karl Townsend" wrote in message
k.net...

First, make sure you got a stone for sharpening HSS - Borazon is best or
soft friable grade pink stone. Or if you're doing Carbide about the only
thing I've had luck with is a diamond wheel - the green one are supposed
to
work though.

For your first few, use a larger cheap HSS endmill that doesn't need a lot
removed. The bottom of your fixture has two flats.One flat gives maybe 20
degree relief for the secondary relief. The other flat gives maybe 4
degrees
relief for the primary relief right at the cutting edge. The unit has
little
ball detents so you can easily rotate the endmill exactly 1/2, 1/3, 1/4,
1/6
of a turn.

This is hard to explain, easy to show. Tighten the endmill and collet in
the
holder so the cutting edge goes straight across. Then place the unit in
the
surface grinder so it grinds on just one flute. 1/2 the endmill is under
the
stone and one flute is coming up right along side the stone. This has to
be
CLOSE but not touch. Too far way and you'll end up with a tit in the
center
of your endmill after you're done. Too close, you'll sharpen the leading
edge off the next flute with the side of the wheel.

Once you're set up slowly lower the wheel and grind off a bit on one
flute,
back and forth. Then rotate the endmill to the next tooth and grind it.
(there are twelve detents on mine, so 6 clicks is 1/2 turn, 3 clicks is
1/4
turn etc etc) Go all the way around, lower the wheel and repeat. On a very
slightly dulled EM you can do only a few licks on the primary relief. On a
bad one, I do the secondary relief first, then finish with primary.There's
specs on the amount of primary relief, but just look at it - the land on
the
endmill should be the same as a new one. On a REALLY bad one, get the
endmill close by hand in a bench grinder first and save some time.

This will give you an endmill that's not center cutting, and has no
"fishtail". But works real good for most applications. For center cutting,
you'll have to learn to gash the endmill first. I do this by hand with a
die
grinder and cutoff wheel under a 10X magnify light. For "fishtail" (center
of endmill relief from edge), you can set the fixture on the surface
grinder
at a 30 degree angle, but with the endmill itself square to the wheel.
(Again - easy to show; hard to explain)

This will take some playing to learn. Spend a day or two screwing up.
After
you get on to it, it only take a few minutes to sharpen the ends.

Good Luck

Karl

Gunner wrote:
I have one of those 5C endmill sharpening fixtures used to sharpen the
ends of endmills. Its a vertical thingy to hold the endmill, with a
couple angles machined into the base of the unit.

How the heck do you use one? Ive found cartoon type generic
illistrations on the net..but were pretty vague. Ive got a bunch of
nicked up end mills that I could clean up on the surface grinder if I
knew how.
I've got some really awful photos (scanned color prints) on my web
site, http://jelinux.pico-systems.com/sharpen.html

I should take better pictures since I have a digital camera, but I
just don't do these regrinds anymore as endmills have gooten so cheap.

The fixture is really meant for a surface grinder, but I figured out how
to do it on a Bridgeport. I've used a pink wheel, but a diamond
wheel does a LOT better job.

As for grinding the side cutting flutes, that is a bit more complicated.
But, it can be done with a spin index fixture. Setting up the exact
height for the guide finger is tricky - very tricky, as a very small
change makes a big difference in the primary relief. But, I discovered
by making the primary relief much larger than normal (maybe 10 - 15 degrees)
you can get an end mill that will ZOOM through aluminum! But, it is
only realistic to do 3/8 and 1/2" end mills without a toolmaker's
microscope.

Jon

"Bob Swinney" wrote in message
...
OK! So howzabout doing the flutes on those same endmills?

Personally, I wouldn't try without a tool and cutter grinder. Technically,
they make an arbor that might work in a surface grinder. I seen a tool and
cutter grinder go for $150 this week, they give 'em away.

I have a Cincinnati Monoset grinder - the Cadillac of this machine group. It
took me a LONG LONG time to get good at flute sharpening. I suffered until I
finally went to a proshop and watched it done. Then the light came right on.
This wouldn't have helped if I hadn't suffered first though.

Here's the best guide I ever seen on the subject:
http://www.hanita.com/hanita_protect...info_start.htm

If you really get into it, I've found a much quicker, more accurate way to
do the indicator drop test for relief angle.


Also a ton of other great endmill information on this site.

Karl

On Fri, 20 Feb 2004 12:11:37 GMT, "Karl Townsend"
wrote:


First, make sure you got a stone for sharpening HSS - Borazon is best or
soft friable grade pink stone. Or if you're doing Carbide about the only
thing I've had luck with is a diamond wheel - the green one are supposed to
work though.

For your first few, use a larger cheap HSS endmill that doesn't need a lot
removed. The bottom of your fixture has two flats.One flat gives maybe 20
degree relief for the secondary relief. The other flat gives maybe 4 degrees
relief for the primary relief right at the cutting edge. The unit has little
ball detents so you can easily rotate the endmill exactly 1/2, 1/3, 1/4, 1/6
of a turn.

This is hard to explain, easy to show. Tighten the endmill and collet in the
holder so the cutting edge goes straight across. Then place the unit in the
surface grinder so it grinds on just one flute. 1/2 the endmill is under the
stone and one flute is coming up right along side the stone. This has to be
CLOSE but not touch. Too far way and you'll end up with a tit in the center
of your endmill after you're done. Too close, you'll sharpen the leading
edge off the next flute with the side of the wheel.

Once you're set up slowly lower the wheel and grind off a bit on one flute,
back and forth. Then rotate the endmill to the next tooth and grind it.
(there are twelve detents on mine, so 6 clicks is 1/2 turn, 3 clicks is 1/4
turn etc etc) Go all the way around, lower the wheel and repeat. On a very
slightly dulled EM you can do only a few licks on the primary relief. On a
bad one, I do the secondary relief first, then finish with primary.There's
specs on the amount of primary relief, but just look at it - the land on the
endmill should be the same as a new one. On a REALLY bad one, get the
endmill close by hand in a bench grinder first and save some time.

This will give you an endmill that's not center cutting, and has no
"fishtail". But works real good for most applications. For center cutting,
you'll have to learn to gash the endmill first. I do this by hand with a die
grinder and cutoff wheel under a 10X magnify light. For "fishtail" (center
of endmill relief from edge), you can set the fixture on the surface grinder
at a 30 degree angle, but with the endmill itself square to the wheel.
(Again - easy to show; hard to explain)

This will take some playing to learn. Spend a day or two screwing up. After
you get on to it, it only take a few minutes to sharpen the ends.

Good Luck

Karl

Many thanks Karl! That makes a lot more sense than the cartoons in
the ads.

Ive got more than a few really screwed up endmills to practice on.
Sigh. But..not as many as when I started G so Im improving.

Gunner

"To be civilized is to restrain the ability to commit mayhem.
To be incapable of committing mayhem is not the mark of the civilized,
merely the domesticated." - Trefor Thomas

On Fri, 20 Feb 2004 12:37:33 -0600, Jon Elson
wrote:



Gunner wrote:
I have one of those 5C endmill sharpening fixtures used to sharpen the
ends of endmills. Its a vertical thingy to hold the endmill, with a
couple angles machined into the base of the unit.

How the heck do you use one? Ive found cartoon type generic
illistrations on the net..but were pretty vague. Ive got a bunch of
nicked up end mills that I could clean up on the surface grinder if I
knew how.
I've got some really awful photos (scanned color prints) on my web
site, http://jelinux.pico-systems.com/sharpen.html

I should take better pictures since I have a digital camera, but I
just don't do these regrinds anymore as endmills have gooten so cheap.

The fixture is really meant for a surface grinder, but I figured out how
to do it on a Bridgeport. I've used a pink wheel, but a diamond
wheel does a LOT better job.

As for grinding the side cutting flutes, that is a bit more complicated.
But, it can be done with a spin index fixture. Setting up the exact
height for the guide finger is tricky - very tricky, as a very small
change makes a big difference in the primary relief. But, I discovered
by making the primary relief much larger than normal (maybe 10 - 15 degrees)
you can get an end mill that will ZOOM through aluminum! But, it is
only realistic to do 3/8 and 1/2" end mills without a toolmaker's
microscope.

Jon

Thanks!

Gunner


"To be civilized is to restrain the ability to commit mayhem.
To be incapable of committing mayhem is not the mark of the civilized,
merely the domesticated." - Trefor Thomas