Grinding woodruff cutter

I need an odd size width and 3/16" radius (5/8" OD). Only thing I can find close is 1/4 X 3/8" radius (3/4" OD) Reducing OD I know what to do.
Need .234" width (15/64). Those I have looks to have the side ground using the radius of the wheel so that the side in concave. Will that work? I'm not cutting a key, depth of cut is only 1/32" in out plunge cut.

They have a very slight side clearance. You might check the one you buy before grinding.
I forget now but thinking about .0003 to maybe .0008 per inch my guess..
I would grind straight sided to your spec width then blue up and come in at a very slight angle..Use a fine grit perhaps 60 or better for HSS ..

(Actually I would make width .0002/.0003 smaller than target width.)

likely the old Niagara tool book shows the amount.


Harvey Tool - Carbide Keyseat Cutters - Full Radius

I checked Harvey Tool. Not what I want. Radius I want is the cutter diameter. Maybe I wasn't quite clear on my description.
If I could find a typical woodruff cutter with 15/64" with of cut and 5/8" cutter diameter that would be ideal. I can live with 1/4" wide X 5/8" diameter but can't fine it. Closest I can find is 1/4" width X 3/4" diameter. What I want is similar to a woodruff key slot 15/64" wide but only 1/32" deep. I looked at a few in my collection some are concaved dished. Others have a counterbore slightly less than the depth of the cutter tooth. But they too seemed to have a radius relief. So what I'm asking is can I use a wheel that will provide the clearance needed and bump it up to the end of the cutter and rotate the cutter to get the width desired.

step over with .125

1 PC # 405 Woodruff Keyway Key Seat Cutter, 5/8" dia X 1/8" width | eBay

grind OD to 5/8
3/4" x 1/4" HSS Key Seat Cutter, .0175" Radius, MF4460355 | eBay

I have a used 3/4" X 1/4" and did buy new made in Poland 3/4" X 1/4" on ebay.

The sides are concave ground.
Done by twisting a bit (2 degrees or so ) and side wheeling.
The dish is determined by wheel OD size.
Rough it flat first by your favored spin grind method and then add the dish.
Bob

CarbideBob said:

The sides are concave ground.
Done by twisting a bit (2 degrees or so ) and side wheeling.
The dish is determined by wheel OD size.
Rough it flat first by your favored spin grind method and then add the dish.
Bob

Click to expand...

Thanks Bob and MIbuck

The reason for the slight side clearance is so they can be re-sharpened with very little loss of width.
Often you use until finding a .010 wear land on the corners. And then OD circle grind preferably between centers taking off that .010 wear land..(some shops leave a whisper of a corner wear land)
Then with adding a 6* primary and perhaps a 12 secondary to a small primary land you resharpen to dead-sharp or to a hair land.(hair land is .003 or less).
Rule to figure OD clearance tooth rest drop is: Diameter x clearance x 87.
Perhaps .750 x 6* x 86 = 387 move the decimal 3 and get .037" finger drop below center to angle for grinding clearance would normally be drop .040.
The multiplier is actually .0087 but we just use 87 and most guys (me ) just use x 9 so to just do it in your head for plenty close enough.
1" x 6 x 9 = 54 so .054 for a one inch diameter cutter
6 x 6 X 9 = 324 so.324 drop (the true drop is .313 but so close little matter)
Clearance spec is +- a half degree and most sharpening hands target spot-on to half degree plus.