Can't keep a sharp edge on work sharp

L

Lennyo3034

Joined
Nov 27, 2012
Messages
490
So I have a work sharp belt sharpener, and am having issues with it. I can GET a very sharp edge with it, however it doesn't seem to last very long. I also have an edge pro, and when I sharpen a knife on that, the edge lasts an order of magnitude longer.

My process on the work sharp is:
Skip the course belt
Medium belt 2-3 passes minimal pressure
Fine belt 2-3 passes medium pressure
Fine belt 4-5 passes minimal pressure
Strop with green compound

Any suggestions?
 
Blade steal can make a difference. Also you're creating a convex grind with the belt as opposed to the a flat with the edge pro.

I really like my Work Sharp and I think you get a killer edge doing what you are doing ... But the convex will not last as long...at least that's my experience.

Strop in between cutting usage...that helps keep the edge. If you are unhappy ...you may have to go back to another system or do some fine belt touch ups more often.
 
I've found that some folks using those WS's have failed to knock off the bur off of the edge which would make the knife go from really sharp to quite dull quickly when the burr rolls or folds in use...

Not saying this is what you've done; only a suggestion. :D
 
Czechmate said:
I've found that some folks using those WS's have failed to knock off the bur off of the edge which would make the knife go from really sharp to quite dull quickly when the burr rolls or folds in use...

Not saying this is what you've done; only a suggestion. :D
Click to expand...

That's what happened to me. Had my PM2 go from splitting hairs to tearing cardboard in an afternoon. Now I'm much more diligent about checking the burr when I sharpen.
 
Insipid Moniker said:
That's what happened to me. Had my PM2 go from splitting hairs to tearing cardboard in an afternoon. Now I'm much more diligent about checking the burr when I sharpen.
Click to expand...


It's harder to tell on the higher end steels I've found as the burr is much smaller than on a cheaper stainless for example.

I still have this happen to me once in a while when I rush through sharpening; most recently with a benchmade 581 barage in M390. I had sharpened it on the paper wheels and had not polished off the burr entirely resulting it dulling quickly in use in a few spots on the blade... :foot::rolleyes::D
 
Your issue has nothing to do with putting a convex edge on the knife. Convex vs. flat is a discussion for another time and many enjoy both. Your issue sounds like a burr and is frequently found with your problem.
Ron
 
IMO it's a geometry issue, the work sharp typically puts a very obtuse edge on a knife if using the guide. It might be sharp but it's so thick behind the apex it has trouble cutting and keeping a edge.
 
rpttrsn said:
Your issue has nothing to do with putting a convex edge on the knife. Convex vs. flat is a discussion for another time and many enjoy both. Your issue sounds like a burr and is frequently found with your problem.
Ron
Click to expand...

You're right...I'll leave that discussion for another place. And I think you all are right about the burr issue.
 
Could be both a bit too broad at the cutting edge but almost certainly has something to do with residual burring. Can be tricky to detect and remove the burr cleanly when using all trailing edge methods, especially powered.
 
Lennyo3034 said:
So I have a work sharp belt sharpener, and am having issues with it. I can GET a very sharp edge with it, however it doesn't seem to last very long. I also have an edge pro, and when I sharpen a knife on that, the edge lasts an order of magnitude longer.

My process on the work sharp is:
Skip the course belt
Medium belt 2-3 passes minimal pressure
Fine belt 2-3 passes medium pressure
Fine belt 4-5 passes minimal pressure
Strop with green compound

Any suggestions?
Click to expand...

With the possibility of a fairly coarse or heavy burr (and I think there is, based on the problems described), I'd try a different stropping compound, other than green. I've never had much luck with green alone, if burrs are anything but very fine. For more tenacious burrs, I like white rouge compound. Some finer blacks can also clean them up very quickly. Since the steel type wasn't mentioned(?), a diamond or CBN compound may also be a possibility, if the blade steel is high in vanadium carbide content (S30V, etc.).

As others have mentioned, the edge angle may be a separate issue too, if it's pretty wide (>40° inclusive).


David
 
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There's a burr left from the Work Sharp or the edge is getting too hot. Do you do any burr removal steps on the Edge Pro that you don't do on the Work Sharp?
 
I feel like you aren't getting enough passes. I do a few passes per side (around 5 or so) after I get the burr up with the medium and fine belts using moderate, light, then phantom pressure (less than the weight of the blade). In between I will strop a little bit on felt or cardboard. If you have the burr built up and use this method with consistent angles, you should be able to shave.

For angles I just hold the blade vertically with the spring roller vertical (makes the edge angle around 17°). Easier to do it that way than use the guides.
 
I keep a cork close by my Work Sharp KO and typically deburr after each belt, especially the coarser ones. I touch up on a Sharpmaker and denim strops, and keep a cork handy there, too.

Andrew
 
I think you guys are right about the burr. One step that I do with the EPA that I don't do with the Work sharp is the strop with an unloaded strop between stones.

The steel I'm mainly using is CPM-M4. The guide angles on the WS are a little obtuse for this, so I usually remove the guide and freehand it. The one knife I've been successful with and stayed sharp has been a Busse in INFI.
 
No need to strop between stones, it's just wasting time.
 
Your procedure recipe leads me to think you need more passes on each grit. I think you are leaving a bur, that folds down after you use the knife a time or two.

Between each belt, run the edge down a piece of wood, to help remove burs
 
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