What Did You Buy Today?

It's either a zero (0) or an O-flute, both names are used and both make some kind of sense.

I've never made one, but I've sharpened them to fantastic results. I love the steel wool they make almost as much as I love the smooth, single-point chamfer. I guess I've never thought to make one because I don't relish the thought of drilling at a 45 on tool steel, seems too fiddly for a simple tool. Especially since it takes me 5 minutes to grind a single flute cutter out of O1 bar stock.
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It's either a zero (0) or an O-flute, both names are used and both make some kind of sense.

I've never made one, but I've sharpened them to fantastic results. I love the steel wool they make almost as much as I love the smooth, single-point chamfer. I guess I've never thought to make one because I don't relish the thought of drilling at a 45 on tool steel, seems too fiddly for a simple tool. Especially since it takes me 5 minutes to grind a single flute cutter out of O1 bar stock.
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Nice machine.
 
It's either a zero (0) or an O-flute, both names are used and both make some kind of sense.

I've never made one, but I've sharpened them to fantastic results. I love the steel wool they make almost as much as I love the smooth, single-point chamfer. I guess I've never thought to make one because I don't relish the thought of drilling at a 45 on tool steel, seems too fiddly for a simple tool. Especially since it takes me 5 minutes to grind a single flute cutter out of O1 bar stock.

John you work that Checkel like a rented mule my man. Please tell me more about your fantastic results. I hadn't sharpened any 0 flutes on mine but I guess this weekend I will give it a try. Are you simply putting a gentle grind 360 degrees around the cutter matching the angles that already exist or is there some warlock fancy pants grindery involved that you can share with a mere mortal foul ball such as myself?
 
John you work that Checkel like a rented mule my man. Please tell me more about your fantastic results. I hadn't sharpened any 0 flutes on mine but I guess this weekend I will give it a try. Are you simply putting a gentle grind 360 degrees around the cutter matching the angles that already exist or is there some warlock fancy pants grindery involved that you can share with a mere mortal foul ball such as myself?

I'm determined to use this grinder for anything that I can clamp in the fixture! Glad you asked, because the first time I tried sharpening an O-flute, I did just what you said with a 360 grind using a toolpost grinder. It worked, but not like it should. I think it was @BGHansen that pointed out that the tool needs relief, so I put it on the Sheckel and sharpened it like a drill bit, or more specifially, I relieved it like two D-bits with their faces glued together, so the O-flute's cutting edge had a prominent leade with relief tapering around the back side for 180 degrees, then relieved the other 180 degrees he same, so that the cutting edges subtly appeared to be on "lobes" when viewed from the bottom of the tool. By making two half grinds, the tool axis is still central to the tool's cone, and the leades contact the work at the same time when centered. Not doing the grind in two 180's and doing it as one leade with 345 degrees of relief (or whatever) would mean the leade catches on the edge to be chamfered and deflects. The O-flute only has one cutting edge.

The O-flute grind was experimental, but now it's my favorite chamfer tool and I have not re-ground it because it works a treat. It a 1/2-3/4 bore size tool. No chatter, no clearance issues, minimal pressure needed to feed the cut, one continuous chip, so I think it's good.
 
Here is a nice countersink made from W1 steel, rough ground, quenched, and final ground. I use it on steel. These take no effort to grind, while building technique. I favor finishing the cutter with a facet, it makes the tool easy to sharpen later. There are different ways to grind rake into the cutter face, but it's not a sensitive tool. As long as you have an edge, leade, and clearance, the tool will cut.

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