Recommendation? Adding the cutting edge to a knife

Not related to sharpening the knife:
Is this blade from the batch you couldn't get to harden?
Did you get that problem solved?

Yes I got my hardening issue figured out. I am on a new batch. I am baking them for allot less time and have a speed oil for quenching. Getting my 5155/SUP9 around 55 hardness and my 80crv2 at about 60. Purchased a larger sander by obm and have the tilt table attachment. Grinding in bevels post heat treat to avoid carbon build up. Only thing left to learn is adding a cutting edge and sheath making. I’ve been doing handles for a good bit of time now so I got that fairly dialed in. Thanks for remembering.
 
It’s a buggy feature🤣. Thanks for your tips.

If knife making were easy, Everyone would be doing it....haha

*Even though sometimes it feels like Everyone is.

-Its Lots of little skills not really used much elsewhere in the rest of the world, so it's going to take a Long time.

I'm not sure how many years it takes (we all learn and know things differently),
but it's years.
 
Yes I got my hardening issue figured out. I am on a new batch. I am baking them for allot less time and have a speed oil for quenching. Getting my 5155/SUP9 around 55 hardness and my 80crv2 at about 60. Purchased a larger sander by obm and have the tilt table attachment. Grinding in bevels post heat treat to avoid carbon build up. Only thing left to learn is adding a cutting edge and sheath making. I’ve been doing handles for a good bit of time now so I got that fairly dialed in. Thanks for remembering.
When your ready for sheaths, I’m around and there is lots of info from lots of guys over at Sheaths and Such here on BF. Very similar to here bout knife making.
 
1/32" is .030" thick. That is WAY too thick for the edge before sharpening.
You want the starting edge to be between .005" and .010" before sharpening.

The starting edge thickness determines the "Thickness Behind the Edge" called TBE. This needs to be thin for the knife to cut efficiently. Many of us take the bevels down to what we call "almost sharp" before making the edge. If you start with almost no edge thickness the edge will be sharp and only take a few seconds to a minute to establish.

Here is how I establish the edge and sharpen.
1) Grind the HTed blade bevels to an edge thickness of .005"- .010". It will almost feel sharp. Some places may be sharp enough to cut your fingers, so be careful.
2) Carefully flatten the edge on the belt grinder at slow speed, or on a stone, to establish a smooth edge with no dips or bulges.
3) Touch up the bevels one last time at 400 grit to make sure the edge is almost sharp and even thickness all the way down the edge. At this point the bevels should be finished except for hand sanding if you are doing more than a 400-grit finish. When you are done with all sanding the bevels, tape up the blade and edge to protect it (and to protect you).
4) Do nothing more to the edge until the knife is finished.
5) When the knife is done except for sharpening I use one of several sharpening methods
A) Sharpen on a stone judging the angle by eye. This is easier than you would think.
Note - Fred Rowe makes a great tool for getting exact angles on bevels and edges called a Bubble Jig. See The Exchange. It will also teach you what different angles look like.
B) Sharpen freehand on the grinder using the belt area between the top idler wheel and the tracking wheel. I have the grinder running very slow and in reverse while doing this. The belt is moving in the direction of spine-to-edge, so it won't catch the super sharp edge. This is what I did 95% of the time before making my new sharpening setup. For a quick sharpening of my kitchen and shop knives, this is what I still do.
C) Sharpen using my edge jig and my new upper platen. This allows exact angles and very sharp sharpening. It takes a little longer to set up but makes better edges.
6) ALL sharpened edges need to be stropped to remove the tiny (sometimes microscopic) wire edge. I do this on a charged leather strop or on a charged linen buff. I don't recommend buffing for those not trained, as it can be very dangerous to both the knife and user when buffing a very sharp edge.
The difference between a sharp knife and a scary sharp knife is in the stropping. Stropping also polishes the edge to make less cutting friction.
7) After stropping, I cut down a piece of cardstock (80-120 pound paper) several times to assure the wire is gone.


TIP:
Sighting down the edge under a good light will show any minute flat spots that are not fully sharp. They will show as "glints". The sharp edge areas will look invisible, as no light reflects off it.
Just checking in….your .005” to .010” edge thickness measurement…..are you talking about flat grinds? Concave grinds? Both? I keep mine at .020” and would like to take it thinner. I grind on a 12” wheel, Bader grinder. What would be your preferred edge thickness at heat treat?

Enjoying this thread. I’ve seen so many Knifemakers leaving their cutting edges too thick, especially new makers…like I was 43 years ago. Thanks for all the responses. Like everyone else, we never stop learning.
 
It really doesn't matter much what the bevel or edge grind will be. It needs to be thin where you shape the cutting edge.

Edge thickness at Heat Treatment is anywhere between .010 for stainless steels to .030 for carbon steels. Too thin and the edge can warp in the quench. Maky makers avoid this by only profiling the blade and hardening with the edge at full thickness. They grind the bevels post-HT.

When talking about "sharp" knives that will cut things (not chopping tools), the edge thickness at sharpening needs to be thin - .010" to .005". This allows for removing the last bit of edge and leaving a sharp apex. If it is thicker, the blade edge will wedge into what it is cutting. The thickness where the angled edge meets the bevel is called the Thickness Behind the Edge - TBE.

Obviously, the intended use determines the TBE and edge angle. A yanagi-ba may be sharpened at 7° and have the minimal amount of TBE. A camp shopper will need a much thicker TBE and higher angle edge. A hand-axe will be very thick behind the edge and have a large edge angle.
 
I grind all my edges on my 2x72 and typically finish with a few swipes across my buffer to knock the wire off. I used to just tilt my platen forward 15 degrees or so and using a work rest and something like a 1-2-3 block or even just a piece of square tube or angle iron, I'd hold my knife at 90 degrees to the rest and carefully grind in my edge using a 220 or a 320 belt. You can go finer than that for sure, but I like a little bit of a toothy edge.
I did that for years until I built a homemade sharpening jig (looks VERY similar to the Reeder jig Stacy showed. Then I'd just set my bar height after tilting my platen all the way back.
I use an angle cube to set my angle.

Since then, the only thing I've really changed is my blade clamp. I picked up one of the self centering clamps that Tormek sells. It centers the blade better than my old clamp, and it's a little less cumbersome to use. I also don't need any tools to tighten or loosen it. The only thing I might do now is make a little auxilliary platen like Stacy shows so that I can get some shallower angles a little bit more easily.
 
What is the most consistent way you all measure edge thickness on a full flat grind? I sometimes go crazy trying to get a good read on my calipers while measuring the edge (trying to get the calipers to clamp the very edge of the bevel and not slightly to high up)
 
It is really easy to do, and for just sharpening it can be a piece of hardened steel. Mine is held in place with one bolt and I can loosen the bolt and drop it so it does not touch the belt if I want to (but have found no reason to yet.) I have found many uses for this small horizontal platen.

One big reason is that running the grinder in reverse is a much safer way to sharpen on the grinder. I could have done that before when using the upper slack belt, but usually I was done with the sharpening before I thought of it. If a blade catches or slips in your hand while running backwards it is not a problem. I cut the heel of my left hand off may years ago sharpening too fast and running towards me. It is my favorite knifemaking scar to show. It happened in a millisecond, and I looked down to see a 50-cent-piece size piece of my palm and glove sitting on the bench. Spent four hours in the ER.
 
You can use calipers and try to just touch the tips on the edge. It is pretty hard to get a good reading. A precision micrometer might work better but is a pain in the arse to read. I haven't measured TBE in many years.

TH truth is it does not really matter what the TBE is as long as it is barely there.

The simple way to get a proper edge thickness is finish the bevels until the edge gets somewhat sharp. Then gently run the edge down a sharpening stone or on the platen with the belt running dead slow. This creates a smooth and flat edge that is only a fer thousandths thick. Sharpen at the desired angle from there. It will slice like a laser.
 
When right, it feels different on the stone. Almost slicker.
Slicing paper sounds diffent, too.
 
I wish I could describe the sound well, but I agree with Craig. The sound of cutting paper after proper sharpening and buffing or honing the edge to remove the wire is a crisp high pitched "Scheeech". You can also feel the difference when cutting the paper when the edge is thin and just right.
 
I wish I could describe the sound well, but I agree with Craig. The sound of cutting paper after proper sharpening and buffing or honing the edge to remove the wire is a crisp high pitched "Scheeech". You can also feel the difference when cutting the paper when the edge is thin and just right.

Yes
Higher pitch.... It Sings....
 
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