Sharpening- Ive lost my mojo

Huntsman Knife Co. LLC.

Huntsman Knife Co. LLC.

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I cant get a knife sharp anymore. Went to the shop today to sharpen my hunting knife for season and couldnt even get it to shave arm hair. I need to figure out whats up.

Ive been using the same process for 5 years

All on rotary platen

1. Set bevel with 120 grit ceramic, work up to burr
2. 320 AO belt for 1-2 passes, work up burr
3. Stop on leather with black compound.

Ive never been great at sharpening but this method has always worked. Now, I keep getting this funky blunted edge after the burr is stropped off.

Only change Ive made is Im now using an economy AO belt from Pops instead of the yellow kingsplor belts. Help me get my mojo back.
 
Sharpening can be frustrating and had been for me over the years. What I do now that gives me a consistent accurate edge is I use an angle cube and set my platen at a specified angle.

I use a 120 AO belt and set the edge until a very slight burr is formed.

I then move to a Edge Pro/Hapstone type sharpener and set the exact same angle for the machine. I use a 150 stone and refine the edge and form a consistent burr. Then move to a 200 AO stone, 400 FLexstone, 600 flexstone which puts mirror finish on edge.

This gives me a known angle consistently time an again.

It is horrible chasing an edge on a belt grinder.
 
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I generally knock the burr off with the sharpener and then polish with the strop. After working up a bur with the first, more aggressive grit I don't think working up another bur is needed as you've already worked the two bevels to meeting at a single point. I've heard of some people that will slice into cardboard or on the wood paddle of a paddle strop to take out pieces of the burr before stropping. If I have a really stubborn burr I will strop on stone or sand paper using very light pressure and then move to the leather strop.

LT Wright's youtube has a few good videos with a belt grinder that should be close enough in application to get a refresher on sharpening.

Part 1 (using shop tools)

Part 2 (looks like all stropping).

Part 3 is sharpening in the field, not gonna link that one. Hopefully these are helpful. Seems like there's probably something small you're missing.
 
What kind of steel is your hunting knife? Sounds like maybe you're not completely taking the burr off.
 
Some knives can have a gummy burr that just won't come off. A cork can be a great way to deal with it but long pulling cuts through solid and maybe grabby will strip that off. Most knives like that I will give a higher and maybe heavy micro bevel.

I use pops value belts all the time and the work great for sharpening. Have you sharpened well in the past on this knife? I made some knives out of 80CrV2 and had sharpening problems like that before. They would be sharp and then I would feel what felt like a little left over burr. When I would strop it the knife would be dull. I couldn't figure out what I was doing wrong. I finally found out that the 80CrV2 needed to be thermo cycled before hardening and that I had just made a crappy blade.
 
I use a parallelogram to control my angle, that helps a lot. 120 grit edge leading then 220 edge trailing. Slow and wet. The last pass is a light one to basically remove the burr on the grinder. A couple light passes on a stone and it will shave, a few passes on a very slow powered strop and it's seriously sharp. I mixed some .5 micron diamond dust in my green shmoo for the strop to speed things up on these high vanadium steels.

We sharpen over a 1000 knives a year this way, it's pretty reliable.

It's important to avoid overheating the edge with powered sharpening. It's easier to do than folks realize.

edit to add: get good green shmoo made for straight razors, not buffing compound, it works better.
 
Not to derail, are folks stropping with leather on paddles or some other, similar device or a leather belt on a sander? I've looked at the leather belts for the sander and it's intriguing for touch ups on bigger choppers that have a convex edge (golok, parang, kuhkri, etc.). Not sure if that's unnecessary at that stage since you're only doing a little work in comparison. The leather on the belt sander makes me think the worry of over-heating isn't worth the little bit of time savings but I haven't tried it and have only started looking into one this weekend.
 
I use a buffer loaded up with green compound as a final step. With aeb-l that is after an x5 finish off the belt,with 440c that’s after a 400 grit finish.
 
I hit it two passes on the charged buffer after sharpening. THEN, I cut five or six cuts through heavy cardstock ( cardboard would work) to revove the final burr. The difference between the first cut and the last are considerable. The edge is super sharp once the final burr remnant is removed.
 
I use a 600 grit belt at about 30 to 35 degrees to leave a nice finish on the bevel. Mostly convex. After this step it has a burr and it doesnt cut very well. Belts leave burrs... dont know why. Be careful not to overheat!
I take the burr off with a sharpmaker at 40 degrees. I use the gray stones. This leaves a hair shaving edge. It only takes a couple of strokes.
Than i use a strop. Any fine compound will do i gues... make sure your angle is similar to the angle of your bevel and try to apply almost no pressure. If you do use pressure of a higher angle the leather can curl round your edge and dulls it. If you do this right, it should be really sharp. Succes!
 
What ever technique is used, being able to repeat the same angle of approach each time is the key. A blade can be made sharp using a convex style of sharpening. The draw back, if you are not using the same pressure on each pass, you may not repeat the same edge that was done previously.
The advantage of using a system or technique that allows you to produce the same angle of approach each time; you will produce the same sharpened edge each time you sharpen.
Leather can be used on the edge to strop, but the same thing applies to the leather, if you don't use the same pressure each pass, you won't produce the same edge.
I use an ERU to remove burrs. It will strop both side of the edge at the same sharpening angle used to produce the burr.

Regards, Fred
 
I consistently struggled to sharpen on my belt grinder. I get far better results on my disk grinder that I have hooked up to my VFD. I set it slow with a fresh 220 piece of paper and set the initial edge. On some I go from there and strip the burr off. On others I will then move to a 400 piece of paper and work through my stropping compounds. I get a much more consistent angle on the disk grinder than my belt grinder.

I did sharpen a cutco knife for a friend the other day and it never felt sharp though the burr was apparent. Some time manually on my strip loaded with compound brought it to the desired level of sharpness. The owner was having a hard time getting it sharp and I think they were struggling to get that pronounced burr off all the way.

YMMV.
 
Hunter, are you sharpening the latest Fell Beast knives that are in 3v? That steel behaves a little differently than 52100 and NitroV/AEBL. Just a thought...the economy AO belts may not be handling that steel as well as they would with 52100/AEBL/NitroV. I would try setting your bevel with the 120 ceramic, then go straight to the black compound/leather strop, at least see what that does.
 
Thanks so much for the replies and advice. I think I've figured out what the issue is.

Stuart, you've nailed it. I tried to sharpen 3 knives yesterday, 2 in Z wear and one in 3V. The issue is the AO belts. They just aren't hard enough for Z-wear and 3V. What's happening is that the grit is quickly being worn off, probably after a single pass on one side, and the dull belt is then rounding the edge over instead of cutting it. So even when a burr is formed, the edge underneath is rounded off and dull. 52100 sharpens up just fine with the AO.

I've actually noticed this phenomenon when grinding bevels. When I'm grinding 3V and a belt starts to dull/ stops cutting, I've often found the belt will still be plenty sharp for grinding 52100.

I'm ordering some 220 grit Ceramics from Trugrit tonight and Ill see if it fixes the issue. I completely forgot that when I did my 3V machete run (20 blades with 17inch bevels) I serendipitously had a bunch of 220 grit ceramic belts left over so I used them for the final sharpening and got really nice edges.
 
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Huntsman Knife Co. said:
Thanks so much for the replies and advice. I think I've figured out what the issue is.

Stuart, you've nailed it. I tried to sharpen 3 knives yesterday, 2 in Z wear and one in 3V. The issue is the AO belts. They just aren't hard enough for Z-wear and 3V. What's happening is that the grit is quickly being worn off, probably after a single pass on one side, and the dull belt is then rounding the edge over instead of cutting it. So even when a burr is formed, the edge underneath is rounded off and dull. 52100 sharpens up just fine with the AO.

I've actually noticed this phenomenon when grinding bevels. When I'm grinding 3V and a belt starts to dull/ stops cutting, I've often found the belt will still be plenty sharp for grinding 52100.

I'm ordering some 220 grit Ceramics from Trugrit tonight and Ill see if it fixes the issue. I completely forgot that when I did my 3V machete run (20 blades with 17inch bevels) I serendipitously had a bunch of 220 grit ceramic belts left over so I used them for the final sharpening and got really nice edges.
Click to expand...

You should try Norax belts, they are great and keep a flat surface and cut great
 
AVigil said:
...I use an angle cube and set my platen at a specified angle.

I use a 120 AO belt and set the edge until a very slight burr is formed.
.
Click to expand...

Adam, when you set the platen to a specific angle are you tilting it forward or back? When hold the blade is it edge up or down? Are you holding it free hand or with spine on tool rest. I am assuming that the blade is held horizontal and perpendicular to the floor as the angle is set on the platen.

thanks
 
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