Well I am not a professional maker but I will tell you what I do, to try and help you out.

So after heat treat I take the edge down to where I want it. Now this all depends on what kind of knife you are making. So if its a big knife like a choppa I take the edge to .025 then sharpen on the grinden using the slackbelt with a worn out 220 grit , then 400grit belt. Then I use a fine india stone and then strop on leather. If it a slicing type knife I take the edge down to .020 to .015 then sharpen it the same way. As far as heat goes just keep dunking it in water after every pass and I only run the grinder at 25% speed. I sharpen it as soon as I am done with doing the bevels on the grinder. Because I want to test it before I do anymore work to it. So I can make sure the heat treat was good. So if everything is good then I dull the blade on a 400grit belt. Finish it and resharpen it on the stone and strope on leather.

That is what I do. Everybody does it deffernt you need to just figure out what works for you.

It also matters what kind of steel you are using some steel can hold a finer edge then other steels.

On the average hunter I would grind my bevel flats until I have a .02” edge before heat treatment. After heat treatment I blend a convex onto the edge with a slack belt that is normally around 3/8” up from the edge with the bevel being completely flat from there up. Extreme care is taken to keep the blade cool during this initial rolling and I never let the knife come to sharp with even more cooling efforts. I do this until subsequent polishing, all the way to final hand finish, will leave nothing but the finest hair line at the edge, and sometimes hand finishing will indeed rudimentarily sharpen the edge. If done right, the convex will blend into the main bevel to the point that it is barely discernable.

The knife is then completely finished out, with the very last thing I do, after the sheath is fitted and I have taken pictures, I will actually sharpen the knife. I find that unless I start with a very aggressive stone I may need to lay the initial edge on with a very slow moving 400X belt. This, as well as any operation that is actually sharpening, is always done wet, especially on a belt. The belt will have cutting fluid applied to it until it is throwing a spray and wetting the blade as it touches it and I never use a stone, of any kind, dry. Like most things I do, there are very sound scientific reasons for this that I have sound data about, but it would be another thread to go into that aspect alone.

If the initial bevels and the secondary roll is done correctly the sharpened bevel will rarely exceed .055”. One can tell how effectively a knife will cut simply by how wide that sharpened polish is at the very edge. When I walk through a show and see edges polished by the stone that approach .125” I don’t need to pick them up to know that they will cut like a cold chisel, and when I see it on a test knife I know the rope cut is not going to be pretty. This is all a result of the primary bevel being too thick, and it can also give you hints as the heat treatment skill of the maker, the more effective the heat treatment, the thinner the edge can go and maintain its integrity. I have never used a sharpening guide of any kind and it did take a few years to develop the skill, but I do believe that a more efficient, and less resistant cutting edge can be obtained by the free hand.

My actual sharpening normally proceeds through two, and sometimes three, stones, all completely wet. When the blade is effectively shaving hair I am ready for the final stoning and honing. When the blade easily cuts a cigarette paper I am there. Honing will normally be on leather strop with some chromium oxide compound rubbed in, followed by some careful work with my fingers. On very fine edges that need to go beyond this, like some kitchen knives, I have a special prototype water stone that was gift from my fellow mad scientist bladesmith in Germany Roman Landes. Many of my early attempts at these types of edges on kitchen knives were simply too thick to take to this level but, over time, I have a learned a bit about the differences.

There are different types of microscopic edges that can be affected by hardness levels, but when I hear makers discussing lowering hardness levels to increase “sharpenablity” a huge red flag normally flips up in mind. Almost any stone will be much harder than the hardest knife steel, and just about every case of a hard to sharpen knife that I have personally encountered has been a geometry issue rather that a matter of hardness. Factory knives with large or obtuse secondary bevels are prime examples of this, and is the main area that custom makers can beat them at. When an unsharpenable factory made knife is brought to me by a friend, I will ask them if they want me to sharpen it so that they have to bring it back to me in the future or if they want to be able to sharpen it easily themselves. If they want the latter, I will basically regrind the knife for them.

Jason, Kevin,

Thanks for your fast responses! So with respect to my concern of overheating the edge and what belt and technique to use, Jason you use a dull 220 grit followed by a 400 grit (sharp?), run at a slow speed, and dunk after every pass. Are there special belts you use for this operation or the same belts you use for grinding bevels?

Kevin - thank you, there is a lot of good information here. I notice you also run at a slow speed and cool by spraying your belt with a cutting fluid. You mention in your 2nd paragraph using a 400 grit belt. What belt do you use between heat treat and the 400 grit belt, such as in your 1st paragraph where you discuss blending in a convex edge? Do you also do that with a 400 grit, or do you use a coarser grit? I am also curious about the belts you use, in addition to the grit size are they J or X backing, ceramic or aluminum oxide? Should I assume you are using belts rated as waterproof, or isn't this necessary?

Thanks!

Dave

The belts I use to start the sharpening are aluminum oxide with a stiff backing not Jflex. The 400grit is a new belt

That is some good info Kevin posted. I'm still dialing in my process too. I have only been taken my edge down to .040 before heat treatment. Next time I'm going to try .020 before heat treat as Kevin mentioned.

I do things similar to the way Kevin does.

I leave my shaped edge at about .025" prior to hardening and tempering.

Following heat treatment I finish shape the edge always with a NEW and sharp 120 grit belt running at a reduced speed. (Once again a huge benefit of variable speed equipment.) I buy these Sankyo economy belts from Pop's knife supply specifically for this use. They are $1.65 apiece and I mostly consider them one-use belts. But they are good enough - and track amazingly well - to finish shape even a 10 inch Bowie.

I float the .025" edge right down to the point where I can almost no longer see it.

Then I finish it with a 400 grit belt of the same configuration.

I will quote my good friend Don Hanson whose knives are so sharp they'll make you believe in Jesus - he says, "I want my knife almost sharp - before I sharpen it."

(When he does a rope cut, the rope falls straight down.)

Thin wins most of the time. Geometry = cut.

Thanks Karl, I appreciate the tips. Thanks again Jason and Kevin. I need to revise the way I get my cutting edge ready for sharpening and now I have a much better idea of how to do it!

Dave

|quoted:

Jason, Kevin,

Thanks for your fast responses! So with respect to my concern of overheating the edge and what belt and technique to use, Jason you use a dull 220 grit followed by a 400 grit (sharp?), run at a slow speed, and dunk after every pass. Are there special belts you use for this operation or the same belts you use for grinding bevels?

Kevin - thank you, there is a lot of good information here. I notice you also run at a slow speed and cool by spraying your belt with a cutting fluid. You mention in your 2nd paragraph using a 400 grit belt. What belt do you use between heat treat and the 400 grit belt, such as in your 1st paragraph where you discuss blending in a convex edge? Do you also do that with a 400 grit, or do you use a coarser grit? I am also curious about the belts you use, in addition to the grit size are they J or X backing, ceramic or aluminum oxide? Should I assume you are using belts rated as waterproof, or isn't this necessary?

Thanks!

Dave

Dave, your question reminded me that I need to be more careful to separate what I teach at facilities away from home and what I do at home with my own knives. Equipment that I have at home allows me to finish things in a different sequence then what most folks normally would. Most of my edge shaping is done before het treatment at home, but those who are working with forges or ovens for heat treating should probably do more of it afterwards. I normally use something like 80X, 120X, or 220X for shaping the roll, with 220X being the most common and the coarser ones for larger chopping blades. I normally just batch jobs up and use up one, inexpensive, aluminum oxide belt for the wet work. I prefer J flex for slack belt work on anything less than the large chopping blades.

Kevin,

Thanks for the update!

Dave