End mill grinding fixture

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dsquire:

--- Quote from: Ned Ludd on September 13, 2010, 08:58:36 PM ---Something is very wrong when Bogs is described as a "newbie" :bugeye: I cannot think of a less appropriate adjective.
Ned

--- End quote ---

Ned

It might say Newbie but just wait till some real newbie or stranger comes along and tries to pull the wool over Bogs eyes. They will be in for a real surprise. :doh:

Cheers :beer:

Don

Lew_Merrick_PE:
Grinder,

Cup-type wheels are most commonly used for this type of sharpening operation. Diamond coated (Borazon) wheels are used for the greatest precision -- and also cost like crazy ($280 US for a 3-1/2 cup wheel). The problem is that you spindle is unlikely to reach a really good grinding speed (usually in the 5000-8000 rpm range) which "suggests" (at least it did to me) that an alternate spindle set-up mounted off you mill head would be a valuable project. Also, be very careful about getting grinding dust into your ways. You really do not want abrasives getting in there. I have a set of leather (suede) "drapes" that cover things and I use a vacuum dust collector when doing such grinding.

One of these days I really need to learn how to post pictures here. I just haven't had the time to dig into the instructions for that of late. I made a "spindle adapter" some years ago that is a plate with a ø.750 round bar (to mount in a collet) index and a split collet that clamps over the (ø3.500 -- as I recall) OD of my spindle to provide a "platform" to attach other tools to my mill's spindle. It started out as a mount for a die grinder so I could use small burrs when doing detail milling. That gets me a 15,000 to 20,000 rpm spindle that is firmly attached to my mill head. I have been thinking about (but have yet to do anything about it) mounting an angle grinder on that "adapter." That would get me an 8000 rpm spindle with reasonable power.

I hope this helps.

Rob.Wilson:
Hi Grinder

That a well made bit of kit :dremel: :clap: :clap: :clap: ,it will save you a good few dollars :med: ,,,,,,,,, thanks for showing :thumbup: ,,,,,,,,, another tool to add to the build list :D

What are the two grinding angles you decided upon for the base ?

Cheers Rob

grinder:

--- Quote from: winklmj on September 13, 2010, 01:15:55 PM ---I've come across a couple of places showing the small diamond disks (Harbor Freight variety) being used. They back them up with an metal backing plate to eliminate the flex.

--- End quote ---
Hi wink,

I tried that, but all it did was stiffen the wheel up to the edge of the washer. The very edge of the wheel that projected past the washer did most of the cutting but still was too flexible. Insted of breaking in half, the wheel broke around the periphery. Bogs suggested that the wheel should rotate so that the periphery of the wheel did the cutting. I thought about this at the time, but had no way to turn the grinding wheel through 90 deg. I think I have to find a way to mount my Dremel tool horizontally :nrocks:

grinder:

--- Quote from: bogstandard on September 13, 2010, 05:15:47 PM ---Just to put things back on track for Grinder.

What you have made looks great, and I am sure with the correct grinding technique, it will work fine.

Just a suggestion now.

If you want to continue to use the grinder you have been using, you just need to change your method slightly.

The grinding 'grooves' should lay at 90o to the cutting edge, the way you are doing it now, your 'grooves' will in fact lay sort of parallel to the cutting edge.

The way to get them laying correctly, feed the cutting edge in the Y axis rather than the X axis as you are doing now.

Line up the cutting edge in the Y axis in line with the grinder spindle, then just feed in on the Y until you have cut the whole cutting edge, retract, rotate to the next edge and repeat. Do not move in the X axis.

I hope this explains it OK.

Bogs

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Hi Bogs,

Thanks for the encouragement. You must be an old hand at this stuff, seems like everyone has a lot of respect for you, well earned I'm sure. :clap:
Anyway, thanks for the suggestions. The way I was grinding the mill is this: I had the setup pretty much as your sketch indicates, but I was using the X handwheel to move the fixture under the grinding wheel. Any grooves cut into the face of the cutter would then be smoothed out by the varying angle of attack of the grinding wheel as the mill passed under. My biggest problem was the fragile wheels I was using.

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