The fellow I utilize for getting my endmills resharpened uses a spin
indexer and common 5C collets. He has a stamped out sprocket attached
that acts as an indexer, and a stop / ratchet type deal and once its
initially set he just advances it the next number of teeth to
correspond with the next flute to be ground.....The el cheapo HF spin
indexer works just fine.
I have a cheap import from Enco, and it was not well made. The
barrel that rotates the collet has a huge amount of play in it.
They depend on the OD of the "plug" that pulls the collet into the
barrel to center the back end of the collet. But, the thread inside
the plug was not concentric with the OD of the plug! No WAY you
can make it work like that.
You could probably buy one of these on eBay for a few bucks, that's
all they are worth. Look it over, maybe try it out a few times,
and then figure out how to do it right.
But, with end mills being sold so cheaply now, I haven't sharpened
an end mill in years.
I also have a ripoff of the Suburban spin fixture. I think you could
do most of the sharpening tasks with that with a lot more precision,
as you can rotate the end mill exactly 90 or 180 degrees without
moving the center or length, as the poorly-made sharpening fixture
allows to happen. If you rig a "finger" to the spin fixture, you
can also sharpen (or alter) the relief on the SIDE of the cutter.
By accident I made some super-hoggers for aluminum doing this.
They had about 3 times the normal secondary relief, and you could
wail through aluminum at incredible rates. (Normal end mills with
5 degree primary and 15 degree secondary relief tend to rub the back
of the flute if you turn up the feedrate too much. There was
no way I could turn the cranks fast enough to cause that to happen
on these "mistakes". But, it is just too much work to do this
unless you have a whole batch of identical end mills (same dia,
same helix angle) to do. You can also buy these special mills,
but they are expensive.
It is a lot of trouble. I did figure out how to do this on a milling
machine. You need a flaring cup wheel, preferably diamond. I have
some atrocious pictures and text here :
about the pics, these are scanned snapshots from a 35 mm camera,
done at least 10 years ago. I can't make new pics because I just don't
do this anymore. I can get end mills so cheaply now, I'd be wasting
my time FAR worse than my USUAL methods of time wasting to sharpen
any more. I could use these setups to make special tools, however.
I should note the construction of the diamond flaring cup wheel shown
is NOT really the right one for this job, and it is hard to keep the
edge sharp. I now have a different wheel that has all the diamond on
one face of a plate. It looks like a Baldor diamond wheel, but has
a 1" (or maybe 1-1/4") hole for a stub milling arbor. I think this
wheel would work a lot better for this purpose, and that's what I would
use if I did it again.
If you have any specific questions, I'd be glad to answer them.
Thanks so far, guys - I have a rotary table, a flare cup wheel,
(one friable, one diamond) and could proceed in that direction,
but was asking specifically about those odd-shaped blocks which
presumably aid in setting the angles corresponding to various
reliefs.... My question stands...
cheers / mark
J> Mark wrote:
I have one of those 5C endmill jigs. It does have a little bit of excess play in
it but I think I can fix it. With one of those, it's easy to sharpen the end of
a common end mill using a surface grinder. No help at all on sharpening the
sides. It helps to understand how to sharpen an end mill, and this knowledge
isn't particularly easy to come by.
I am by no means any kind of expert on sharpening endmills, but have
watched it done quite a few times, but did not pay any particular
attention to it as it was something that would always be out of my
reach or need due to associated equipment costs and space.
From what I have learned, it basically takes an ain spindle/arbor, and
once it has the endmill mounted in the collet, and indexed, its merely
pushed into the stone, with a finger following the flutes to rotate it
along its helix. Thats for the side grinding of the endmills....Pretty
hard to do it and do it correctly without the air spindles.
The ends are ground on a free sliding ..glideing type table after each
endmill is indexed for the ends, and fed into a grinding stone,
endmill rotated to next edge and slide back into the grinder
again...This process is doable on a surface grinder or even on a mill
with decent results for touching up or resharpening the ends, but
unless you have the air spindle fisture your just spitting in the wind
with trying to do any touch up of the sides.
I have always been amazed with the amount of grit and metal grindings
on those grinders that do the ends, that they usualy always move with
just the slightest touch.....you can practically look at it and make
it move. Same for those air spindles.....think move and it moves...
The fellow I know covers all edges he intends to grind with red magic
marker as a reference.