Problem Sharpening (need help)...

L

lasersailor184

Joined
Sep 15, 2003
Messages
77
Ok, I'm rather new at this, and at sharpening too. But anyway, I bought a 40 dollar KABAR at the local gun show recently. I also bought just a cheap two sided coarse / fine whetstone from sears.

The problem comes with sharpening it. Using the coarse, I can get the bur to come out and stuff. It's kind of sharp, but has little dinks missing from parts of the bur breaking, but not the whole bur.

So I switch to fine and do the one pull per side and switch thing. For some wierd reason, the knife comes out rather dull.

Am I doing something wrong? Should I be doing something else?
 
I'm not very familiar with wetstones, but I do know that when I have used them, they don't work very well. A cheapie from Sears isn't going to do the job very well at all. If you insist on using a stone, get a true Arkansas stone, they work pretty well depending on your technique and type of knife. I use, and highy recommend, ceramic sticks. You don't have to get the Spyderco Sharpmaker to have a good ceramic system either, unless you do a lot of sharpening and want it. I bought a set for $15 from my local knifestore and it's awesome!
 
Joe Talmadge made an excellent FQA on sharpening. You can find it on google groups: Here

After making the burr on both sides using the coarse stone, you should make a burr on both sides useing the fine stone. Then you should gradually use less and less force, ending with only the weigth of the knife.
 
Providing you were keeping the same angle for both stones, I would suggest your knife wasn't really sharp before you switched to the fine side. Instead I suspect what you were experiencing was the phudeo-sharpness of the burr, which as you found out breaks off easilly, the burr gives the allussion of sharpeness, without actually being sharp.

If you are going to carry on with the whetstone (no reason why not, but a ceramic "V" sharpener might be easier for a beginner), then I would suggest you cut off the burr (run the edge down the face of the stone), and start over. This time go slowly on the coarse side and stop just before you begine to form the burr, using a permanent marker on the edge is a good way to do this, then switch to the fine side and bring the edges together with the least amount of burr as you can. Takes practice, but your knife will end up sharper and keep it's edge for longer
 
The marker trick is very useful, that might help solve your problem. Keep in mind that hand sharpening is actaully pretty difficult to learn, it took me at least 4 years of practice before I got any good. I didn't have Bladeforums to help me with my technique, I just learned through trial and error. With the knowledge base you've found here you should get the hang of it a lot sooner. Good luck.
 
A cheap whetstone from Sears will work fine, particularly on a carbon steel blade like a Kabar (I assume that you are talking about an old style combat utility sheath knife). A brand new coarse whetstone is often pretty irregular particularly if it is a silicon carbide hone rather than an aluminum oxide hone. If you are not holding your blade perfectly horizontal across the stone you may be partially scraping your blade along the ragged edge of the hone. This is an easy way to get some dings in the edge.

It might make your life simpler if you smooth the long edges of the stone a little before you go further. Take your hone out to a reasonably smooth stretch of sidewalk and rub the long edges longwise on the sidewalk. You want to make the edge feel a bit smoother so it is better to rub lengthwise rather than crosswise to the edge and it is best to use smooth cement. Alternately you could use the back of some floor tile or some 90 to 120 grit silicon carbide paper. Like I said, this step is optional, but it makes honing less demanding.

Back to actual honing issues. Again, a new hone is kind of rough. You want to break it in quickly and get a smoother edge. Try using water with a little dish soap on the hone as you work. This will reduce drag and break the stone down a little quicker.

Now lets try and get a decent rough edge on the knife using just the coarse hone. Set the hone coarse side up on a counter or workbench where it will not slide. First lets eliminate any funny burr that you might have created previously. Use the full width of your thumb as sort of an angle guide. To remove a burr you want to hone lightly, stroking edge first (not back and forth, not circular motions, and most definitely not stropping with edge trailing strokes) and you need to do this at around double the angle you would normally use to hone. So lay the edge of your blade on the hone and put the width of your thumb under the spine of the blade. This will give you about a 5o degree angle. Do a light edge-first at this angle. Flip the blade over and do a stroke at around the same angle from the other side. Repeat this pattern about 10 times. Try not to dig the edge into the edge of the stone while you do this. Do this until the edge looks and feels smoother. Not really sharp, but a nice even deburred base.

Again use the side of your thumb as an angle guage. Press the middle of the pad of your thumb against the spine of the blade. If your thumb is about one inch wide and your knife blade is about 1.25 inches wide you would get a honing angle of about 24 degrees if you layed your thumb and the edge of the blade on the hone surface at the same time. This is steeper than we want. Offset your thumb on the spine of the blade so that there is a little more on the side away from the stone than the side against the stone. You are in the general 15 to 20 degree range. This is where you want to be. Because your stone is new you want to hone fairly lightly. Using the side of your thumb as a guide hone one side of your blade (this will be the left side if you are right handed) using edge forward strokes. Edge forward will reduce burr formation. Do this until you can feel a little burr formation on parts of the edge on the side away from the stone.

When you start to get a burr switch sides. On the other side of your blade use your index finger as a guide. Since it is narrower than your thumb just center your index finger pad against the spine of the blade. That should give you around a 15 to 20 degree honing angle. Hone lightly and smoothly edge forwards on this side until your feel a burr along most of the blade.

Unfortunately now you need to remove this burr. Hopefully it is not too big since we have been careful. Repeat the general burr removal procedure we started with at the same high angle, but be specially careful to go lightly and smoothly on alternating sides. Only do this for about 5 strokes per side.

Now you need to do some freehand honing to get an edge on the blade. You want to hone on alternating sides, edge forwards, at just a little higher angle than the 15 to 20 degrees you used to set the edge. Use the spine against the middle of your thumb to show you what 20 to 25 degrees looks like. Very lightly hone alternating sides of the blade at this angle. Be careful to avoid the edges of the hone as you work. With about 10 strokes per side you should have a real mean edge. This would be a nasty rough combat edge that will cut like a serrated blade.

For a more refined edge switch to the finer side of the hone now. Use the same thumb width position that you used for raising your initial burr. Do about 10 edge forwards strokes on the left side. Switch to the other side and use the middle of your index finger as a guide and do about 10 strokes. Go back to freehand honing alternating sides at the slightly increased angle you used to finish your rough sharpening. After about 10 strokes per side you should be done.

Drag your finger tips from the side of the blade off of the edge. You are feeling for a roughness of a burr. Try several places on both sides. If you find a burr go back and do just a couple deburring strokes per side very lightly on the fine stone at about 40 degrees. Now finish by stropping the blade on an old leather belt. This is done edge-trailing working opposite sides with the blade bevel almost flat on the belt. A carbon steel blade like a Kabar will really perk up when you do this. It should shave at this point.
 
Kudos, Jeff, for taking the time to put together that very nice little treatise. :cool:
 
Awesome, thanks. Just a quick Q jeff before I do anything I shouldn't be.

Again use the side of your thumb as an angle guage. Press the middle of the pad of your thumb against the spine of the blade. If your thumb is about one inch wide and your knife blade is about 1.25 inches wide you would get a honing angle of about 24 degrees if you layed your thumb and the edge of the blade on the hone surface at the same time. This is steeper than we want. Offset your thumb on the spine of the blade so that there is a little more on the side away from the stone than the side against the stone. You are in the general 15 to 20 degree range. This is where you want to be. Because your stone is new you want to hone fairly lightly. Using the side of your thumb as a guide hone one side of your blade (this will be the left side if you are right handed) using edge forward strokes. Edge forward will reduce burr formation. Do this until you can feel a little burr formation on parts of the edge on the side away from the stone
Click to expand...

This part I should be pulling away from the edge of the knife?

Now you need to do some freehand honing to get an edge on the blade. You want to hone on alternating sides, edge forwards, at just a little higher angle than the 15 to 20 degrees you used to set the edge. Use the spine against the middle of your thumb to show you what 20 to 25 degrees looks like. Very lightly hone alternating sides of the blade at this angle. Be careful to avoid the edges of the hone as you work. With about 10 strokes per side you should have a real mean edge. This would be a nasty rough combat edge that will cut like a serrated blade.
Click to expand...

And this part pushing towards the edge?
 
It's hard to add anything meaningful after Jeff's post, but here's some food for thought. I’ve purchased many knifes, mostly carbon steel knives, that had some bad problems toward the edge. The blade was generally well heat treated, but the steel right at the edge was oddly brittle. I don’t know if it was from the heat treatment or the grinding of the edge, but something was messed up. Merely honing a bit of the steel off the edge got me to the sweet part of the steel, and no more sharpening problems.

All I’m saying is... It might not be you. It might be the knife.
 
You virtually never pull away from the edge (strop) with a rigid hone. That is how you end up with a burr that never goes away. It pulls loose material up to the edge where it flops to the other side and forms a week burr. Honing on a stone is virtually always done edge first. This pushes the burr back towards the blade where it is more inclined to get cut off. So in my instructions the only place that you work the blade with the edge trailing is the last step when you strop it on a leather belt.

With the hone that you have do all of your honing edge first. Once you have gone through the full sharpening process and you have a shaving edge then you could experiment with a little bit stropping on your hone. You have to have a clean edge with no burr before you do that. At this point in your education you should concentrate on edge first. It is the fundamental approach to creating a sharp and strong edge. If you feel you need to strop get some buffing compound and put it on an old belt. When you finish honing try some stropping with this compound an the belt.
 
Definitely an archival-quality post there, Jeff.

Just a couple comments, lasersailor ... new knives (and other edged tools) often need a considerable amount of work before they'll take and hold a quality edge. A lot of factors may be involved, I'm sure, but mostly having to do with a certain amount of unavoidable/unintended differential heat treat, and then some burning or annealing of the steel during the factory sharpening process. Plenty of times, I've seen grinds that had to be moved back a good 0.010"-0.015" before you could establish a decent edge.

One thing you can do with a stubborn burr or wire edge is to do some cutting of something tough with the knife -- wood, plastic, even just heavy cardboard in some instances -- until the burr is knocked off. Now when you go back to your medium or fine stone to clean up the edge, chances are very good you'll find the burr you form is much smaller, a lot "crisper", and comes off easily when putting on that final edge. If not, then you start to suspect something's wrong with the steel or heat treat in general.

If your Ka-Bar continues to be stubborn, it could be that the steel is just a bit soft for the edge angle you're sharpening at. Remember that hard-soft is a trade-off with knives, and for a fighter/utility knife like yours, a little bit softer steel means it's less brittle, and therefore tougher for certain uses. Sharpening at a slightly greater angle may help. I've also found that going to a convex edge, as opposed to a "V"-type edge, can be advantageous with knives like this.

Good luck!
 
i recently purchased athe blade masterfrom frost cutlery, it has three stones, aknife clamp an angle guide and honing oil. it makes sharpening a no brainer and it was fairly inexpensive. you may want to check one out.
 
Thanks guys. Those frost cutlery sharpening kits are very tempting.


But anyway, that box trick it seems also works well with giving a "Pull cut sharp" knife just a little bit more sharpness.
 
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