grinding final edge on the blade

Jack142 · Nov 19, 2002

Hey guys, its time for some advice again. I have a knife all done, now all I want to do is grind the final edge on the blade. What grit of belt / belts do you guys use ?

I dont want to screw the knife up no that it is almost done, I was thinking of 600 grit and then use my Lansky.

The blade has no edge on it now. Its needs grinding before a stone.

Also, I gotta tell you about a "tool" that I made. I didnt like the way the epoxy glue was going on my handles. It was always too heavy and messy.
Well, if you have put down linolum floors, they have a trowel with flat teeth cut into the edge. When you scrape the floor with it, it forms ridges in the mastic, that way when the floor goes down you dont have too much mastic on.
Well I took a piece of flat 1 inch alumimum , gound it like a chisel, and then used my dremel to cut five teeth into in, 1/8 inch deep. Then I flatten the edge a bit. That made the teeth about a 1/16 in deep. I spread the glue on with it and run it down the handle. It removes the excess glue. The glue overflow is not nearly as bad now.
And so far its seems to be a good idea.
Thanks for the advice on grinding that final edge
Jack

itrade · Nov 19, 2002

Don't use the Lansky.

I used one (and a Gatco) for years. Then I found that idea has 1 major problem. The angle changes as you move away from the clamp. The effect is that the final edge changes width. Nearest the clamp is narrow and it gets wider as you move away. This changes the final angle too. Leaves an inferior edge. Another problem is the marks left by the clamp.

You can certianly use the belt grinder. I've tried it, but I don't have a speed adjustment so I don't use it - things just happen too fast. Practice on some junk kitchen knives first, of course.

(warning: soap box)

If you have a bench grinder, spend the $20 for a set of paper wheels. You'll never go back. Neat, clean, doesn't need to be flattened like stones do. sharp, polished, yaddity yaddity yaddity.

Koval's calls them "Koval's Extra Sharp Sharpening Kits"
Texas knife calls them "Professional Knife Sharpening Wheel Set"
Sheffields calls them "Sheffield's Ultra Sharp Sharpening Kits"
K&G calls them "Knife Sharpening Wheel Kit"
Jantz calls them "Knife Sharpening Wheel Set"
Jantz description: "This 2-wheel system will allow the user to grind a fine edge then clean and polish to an unbelievable sharp edge."

There's a reason all the knife making places carry these things. The amazing thing is the price is less than a single diamond stone!

Steve

Jack142 · Nov 19, 2002

Steve,
The edge on my knife is at about 1/16 of an inch thick. Maybe a tad less.
I thought I had to at least bevel (grind) the edge to some kind of sharpness before I use something like a Lansky or sharpmaker or a paper wheel.
I been reading a bit about them (paper wheels) and I think I am going to send off for them. what is a few more bucks spent on knife making anyway !
Thanks for the advice,
Jack

Danbo · Nov 19, 2002

I use the slack part of my Bader BIII and convex the final edge on. If you are really careful, it is quite easy. Just make sure not to come close to overheating the edge. For this reason, I dont use superfine grit belts for the actual edge. Too easy to build up heat.

itrade · Nov 19, 2002

I thought I had to at least bevel (grind) the edge to some kind of sharpness before I use something like a Lansky or sharpmaker or a paper wheel.

Oh gotcha Jack. Don't think that is necessary.

BTW you mentioned the width of the edge. Reminded me of some math I've always wanted to try.

If the included angle you want is 25 degrees. And the edge width on the knife is about .030. Then using a tangent you can find the width of the final edge.

Tan(12.5) = .22169
thickness of the blade = .015

then width of the edge would be .015/.22169 = .068. So that's about 1/16th of an inch.

With the same angle and the edge thickness on the blade is .040, then:

.020/.22169 = .090 which is about 3/32"

Gee, if I measure the blade thickness and then the width of the edge I could get the angle.

I suppose math has some value.

Just babbling.....

Steve

Jack142 · Nov 19, 2002

Geez Steve,
I was a math major in college too too many years ago, I should be able to do the math. Ha ! I havent a clue ! Where is all that memory I am suppose to have.
Jack

Matt Shade · Nov 19, 2002

I've only done it a few times, so take this for what its worth.
I use a dead 120 grit belt. Its almost got a shine on it now. Alternate with a half dozen or so passes on each side. Make them quick and don't use alot of pressure. Dip the blade pretty often to keep it cool.Get it as sharp as you can that way, then move on to however you normally sharpen.
Surprisingly, the last knife I did this with would shave a little with just a little stropping after grinding. Had to go back an use stones to get a good edge though.

Will52100 · Nov 20, 2002

I think everbody has there own methoud, you just have to find what works for you.

I generaly put a convex edge on, and this is how I do mine. While grinding with the finner grits, 220 and up, I put the edge on with the slack part of my grinder. Just make sure you dont' over heat as was stated. After finishing on a slow, dull, and lubricated 400 grit it's pretty sharp. I continue to sharpen as I'm handrubing, just be aware that the blade can bite you, and don't leave it in a vise. I clamp a block of wood in my vise and clam the blade to the wood so I don't tangle with the edge.

After finishing the blade it's pretty well sharp, I tape the edge untill I finish the knife. Then I touch up the edge on a norten fine India stone, then a couple of passes with a fine Arkansaw oilstone to polish the edge a bit. This produces an edge that most custimers can replicate without too much trouble.