Critique my sharpening technique please!

peripatew

peripatew

Joined
Jul 31, 2007
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For some reason, I'm not overall impressed with how the edge of my knives are turning out. This is on knives I make, and on knives that I'm just sharpening. They seem sharp, but for one reason or another it seems like I could be doing a better job. I'll describe how I'm currently doing it, so those more experienced can try to see where I could improve.

I do everything on an old Delta 1x42". Depending on the condition of the edge, I start with a fresh or sharpening only use 220 belt (I've never needed to use a 120 yet). I give it a few passes on each side, trying my best to maintain a consistent angle on each side (sharpening against the platen). Then I move to a 400 grit belt, give two passes on each side (sharpening against the platen). Then I move to a loaded leather belt, rough side out. I'm loading it with a generic chrome paste that I got at a local hardware store. Of the sharpening compounds that they had, this one listed the smallest particle size. It is gray. I load the belt lightly, and if to much excess is on the belt, I clean it by holding the spine of a blade against it to scrape off any clubs. I'll make 2-3 passes with the leather belt, starting with one pass on each side against the platen, edge down, and then moving up to the slacked area and make an extra pass or two.

This creates a highly polished edge, that will easily push cut just about anything, and it slices smoothly through paper. I can run my finger nail across the edge and I don't feel any inconsistencies in the blade edge. And it will shave arm hair easily, but arm hairs don't run and hide.

For some reason, the performance of the blade just doesn't seem to be where I would want it. Its hard for me to explain the lack of performance, but it just seems like somethings wrong!

Any thoughts or critiques. Thanks! Let me know if I need to provide more information.
 
You seem to be following a standard technique, however at no point did I see you mention a wire edge developing. Before you strop with the leather belt make sure you see that develop at the apex of your two grinds. Also, what is the beginning thickness of your edge before the 220? For small knives it should be a 1/2 to a 1/4 thickness of a dime (IMO) or less and for larger (chopper 8" blade or larger) maybe a 1/2 that of a dime. I use a dime as a reference as a lot of people have dimes, not everyone has a caliper. :) Last thing, what angle are you holding your blade to the belt? I try to hold it at approximately 20 to 25 degrees and use a well tensioned belt in the slack area. You will get a very slight convex, unless you press too hard, then you get a major convex. You only want the slight convex at most to make it easier for a laymen to sharpen that won't necessarily have access to a belt sander. Hope this helps....
 
have you tried a more aggressive edge, ie skipping the compound and stopping at 220 or 400. This will make a more aggressive slicing edge.

Only other thing I could think of off the bat is maybe you are convexing a little heavily on the slack belt. The edge may not feel as keen then if the final included angle is bumped up by the give in the belt.
 
Sounds sharp to me. The type of performance you are after depends on the edge. A true V bevel will perform differently than a convex. I have had knives that just didn't have that hair popping edge , but performed second to none in the field. On your next one go for a slight convex edge and see if that performs like what you are after.
 
I would say to do all your sharpening on a slack belt and not use the platen. Light pressure on the slack belt only and make sure you get a wire edge prior to going to the leather strop belt. This will give you a slight convex edge that should be plenty sharp.
 
jkf96a said:
A Greek student, eh? Hard to make knives when you're walking around :)
Click to expand...

I have to sharpen the knives to I can walk around! :D Abilene... any connection to ACU?

Thanks for all the help.

I do develop a wire edge when sharpening as described above. I'll have to experiment with sharpening only on slack vs the platen. As well as some different angles.
 
I suggest trying to sharping on the slack of the belt instead of the platen. I use a 320 or 400 grit belt and then go to a wheel or cork belt with compound.
 
The only thing I can think of is that 400 grit to a polish is a pretty big jump...perhaps you are creating polished scratches and not a truely polished edge? Shaving sharp is usually "sharp enough" but a lot has to do with the edge angle. You could create a knife with a shaving sharp edge but if its a thick, obtuse angle, it still might not cut as well as a duller, thin blade.

I use an edgepro now, and go through waterstones from 120-220-300-800 then to the polishing tape before stropping. Its crazy overkill, but puts an edge one the knives second to none.
 
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