How I grind bevels
I don't know if this will be helpful or not, but I will try to describe how I do a flat grind. First off I'm using a 2 x48 Kalamazoo for a belt grinde . I know its not a 2x72 but it fits in my budget and works fine for me.
I was having trouble free handing bevels and getting the same angle on both sides so I built a jig. Basically it is just a piece of1 1/2 angle iron about 4 1/2 inches long with a knob mounted in the center on the bottom inside and two brass bolts going through the other side about 2/3s of the way down from the top. The knife to be ground rests on those bolts that stick through the angle iron bevel up. On the tool rest I added a piece of 1/4 by 3 by 12 inches long , it is drilled and treaded so it can be clamped to the stock tool rest.
Now comes the hard part. To figure out what angle to set the tool rest to I measure my steel and divide it in half, then determine how wide I want the bevel in thousands. Then using a scientific calculator I divide half the thickness by the width of the bevel I want and then inverse tangent, that should give the angle to set the tool rest. To do that I use a digital angle cube zeroed on the belt and then set the tool rest to the angle I need.
This is not a cure all I think it probly won't work for every knife but it works for me so far.
I haven't been here long enough to post pictures in a thread I don't think but if you look at my profile I have some pictures of this jig in an album, I think everyone can see them. I hope this is helpful for someone. If this looks like it will work for you but you need clarification let me know.
Sam
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