How to get rid of a wire edge?

B

bigbass

Joined
Mar 26, 2001
Messages
70
I am getting knives sharp on my sharpmaker but if I hold it at the right angle in the light I can see a wire running the length of the blade at the very edge and I just wanted to know how to get rid of this. Should I be leaning the knife outward more toward the stones in order to match the blade grind angle better to the stones? I hold it perpendicular to the ground right now. I am talking about when I have made a touch up with just the fine stones. I am talking about a CRKT KFF in particular and it doesn't seem to have a very wide bevel, which from what I have read here is usually the cause of a wire edge. Thanks guys.

[This message has been edited by bigbass (edited 05-11-2001).]
 
First, as you progress to the white stones, lighten up on your strokes as you go. This will keep the wire edge from growing, at least, and hopefully let it get smaller and smaller.

In my opinion, the best way to get rid of the wire edge is through double-grinding. When you're done sharpening, do this: Put the knife on the left stone. Instead of holding the blade perfectly perpendicular, tilt the spine in towards the center of the V slightly. Now, take a very light stroke down the stone. Move to the right stone and repeat. Go back to left stone, try to match the same angle again, this time let the blade go down the stone with just the weight of the knife pushing it down. Repeat on right stone.

I take 2 or 3 strokes per side when double-grinding. Between the fact that you're doing this very lightly, and the fact that the angle has been raised a bit, the burr usually comes right off. I feel this is a better solution than stropping, because with stropping you're more just flopping the burr back and forth until it pops off, and that does not leave quite as perfectly clean an edge as double-grinding it off. I'm oversimplifying on stropping, but I do think double-grinding is a better and more reliable way to remove the burr.

Often, just in case, I combine the two. First I double-grind. Then I take a few strokes on a strop. Between the two, that usually finishes the burr off for good. Note that some steels tend to have a "floppier" burr, and it's harder to get that kind to grind off. Furthermore, depending on heat treat, you might have differences even within the same steel.

Good luck!

Joe
 
Doing it at a slightly larger angle can achieve this, but you're also risking to ruin the edge if you put too much pressure. This is easier done than said, so go ahead and try it. Another method is to back off to the coarser stones (the black ones) and stroke very ligthly. I usually do a couple of strokes on each side.

One popular method, and this is my favorite: use a strop. If you have a leather strop impregnated with polishing compound it is mighty great, if you don't you can also use an old leather belt, old jeans, or the back of your notepad.
 
Getting a wire edge is a GOOD thing. It means that the angles ground on the stone are coming together at the edge. As the edge gets thin, sharpening will push some of the thin cross section of metal over the the other side, creating the wire edge.

You can remove it on a fine stone by drawing the blade Away from the edge or use a polish coated leather strop. Another quick technique to remove a large wire edge produced by coarse stones is to pull the knife back to tip through the edge grain of a piece of wood. Stropping after doing this will refine and polish the edge.

Make sure to read Joe Talmadge's Sharpening FAQ here at BFC for more good tips on sharpening.

Paracelsus

[This message has been edited by Paracelsus (edited 05-11-2001).]
 
I had never even considered that Joe! I will give it a try on the next knife I need to sharpen. Thanks!

------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto

A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
 
I use Joe's method. I think of stropping or edge-trailing honing as a backward approach to removing a wire edge. The wire edge is very ductile like aluminum foil. A stropping stroke primarily wants to bend the thin material over to the other side. You want to apply light pressure, but high abrasion to the base of the ductile area. The best way that I can think to do this is to slightly increase your angle and apply light pressure with a rod with sharp abrasive grit. A diamond coated rod might be ideal. It seems to me that a round rod or the apex of a triangular rod would cut the best and fold the burr over the least. A strop is the opposite of this.

If you want to observe wire edge creation on a macroscopic scale and get a better feel for how it works, try sharpening Popsicle sticks by rubbing them on a sidewalk. See what kind of effects you can get from honing, stropping, back-and-forth rubbing and adding loose sand to your work area.


[This message has been edited by Jeff Clark (edited 05-11-2001).]
 
Joe, I just have one question for you. When you meant to turn toward the center of the V did you mean away from the stone you are using or toward it? Thank you for your help.
 
PS. Matching the blade's factory grind (low angle honing) only increases the tendency to create a wire edge, but it makes the edge sharper. I do that till I get the wire edge, then I increase the angle and take off the wire edge, then I go back to the low angle for a few strokes to minimise the blunting effect of the higher angle used for burr removal. Working alternate sides with edge-forwards honing generally minimizes wire edge creation.
 
<font face="Verdana, Arial" size="2">Originally posted by bigbass:
Joe, I just have one question for you. When you meant to turn toward the center of the V did you mean away from the stone you are using or toward it? Thank you for your help. </font>
Click to expand...

Turn the spine of the knife slightly away from the stone. The goal is to raise the sharpening angle very slightly. If you tilt the spine in towards the knife, you can see the sharpening angle gets reduced, which doesn't buy you anything.

I'll re-emphasize that you have to use a light touch when you double-grind. If you push too hard, you'll just create a new burr. Just the weight of the knife itself, with perhaps a tiny bit of help, is all that's needed for the first stroke, and all subsequent strokes should be driven just by the weight of the knife alone. Frankly, to be safe, it's not a bad idea to just use the weight of the knife for all strokes.

Joe

 
First, I will confess I NEVER could sharpen a knife on a stone...try as I may...
given that...I would like to say the best.. that is BEST way to finish/polish the edge is with a hard felt wheel on a buffer.

------------------
http://www.mayoknives.com
John 1:14
Love is Stronger than Death!
 
Excellent advice, Joe.

The whole topic of sharpening is, IMO, complicated and not really well understood by the average knife owner. I've seen too many guys butcher their blades by improper sharpening techniques.

This might be a great topic for a video, giving real insight into the micro-mechanics of the process of putting a really fine edge on a knife.

I have Sal's, with the 204 and it's good for most purposes, but maybe an "advanced class" for those who are real fanatics on the topic.

Just a thought.

------------------
----------
Dick
 
eek.gif
GOD YES! I asked a little while ago if Spyderco would do this, no reply
frown.gif


Anyone else willing to do this?

------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto

A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
 
That sounds like a great idea. I think many of us use basically the same technique, but there are a lot of guys who I would like to learn from who here-and-there use slight mods on what I do, guys like Cliff, Para, Jeff, etc. So I'd love to see a small series of them.

I'd threatened to do a quick backyard video years ago. I could handle making some copies of a video tape, but I suspect we would have scores if not hundreds of people asking for copies, and I just don't know how to accomodate that. Anyone have any ideas here?

Since I got a video camera on my computer, I've been thinking I could just ask people to contribute to a web-based video show account, and then I'd upload it straight there. But this camera isn't the greatest, and I don't know how grainy it will come out, much less how many people have connections fast enough to get something out of streaming video.

Joe
 
I use both methods to remove a burr ... the strop and the "knock the burr off with a slightly steeper angle on the stone" approach. I guess I resort to a final touch up by stropping, out of necessity, about 1 in 4 re-sharpening exercises.

I defer to others as to which is really better, they both work for me. The idea that a "snapped off" burr from stropping leaves a less refined edge makes sense. Personally, I'm rarely going for a polished, refinined shaving edge ... instead preferring a toothy, grabby working edge, so I had not noticed a difference, but will consider this if I decide to go for a polished edge for some reason (leather work? Shaving my wife's ... uh ... legs with my Starmate?)

One quick point... the idea behind using the strop method is to capitalize on the phenomenon of cold worked metal fatigue. You can induce fatigure by bending the burr back and forth. It is the same concept as taking a piece of wire, and bending it rapidly back and forth to weaken it at the bend and allow an easy "break" in the absence of snips/dykes. Some metals or heat treats seem to be harder to fatigue, but I haven't payed enough attention to say specifically which alloys/vendors, etc.

Since you are trying to bend it back and forth to fatigue the wire edge, holding the blade at an angle slightly higher/taller (larger numerical degree angle) than that used to sharpen is necessary. Use light use pressure or risk rounding off your new base edge, and flip sides after each stroke or two. This seems to work better with larger burrs ... where you've raised a signicant burr for whatever reason (reprofiling a knife to a different angle for instance). But it seems to work ok with a small burr too, e.g. a quick retouching of an alread-reprofiled blade.

I often strop with whatever is laying around ... magazine that's headed to trash anyway, cardboard box edge or flat, paperback book, etc. After you get the hang of it, you can strop on lots of stuff. I leave one side of an empty cereal box (plain uncolored nappy side is side to use) laying around to use out of laziness, but of course I have two leather strops if I need to get resort to those, but that means getting off the couch to fetch them. I don't usually have to leave the couch, in all my spud-like sharpening-while-watching-the-tube in blissful glory.

BTW Joe Talmadge, that FAQ is a really nice piece of work...great service you've provided for the right price!

[This message has been edited by rdangerer (edited 05-13-2001).]
 
<font face="Verdana, Arial" size="2">Originally posted by tom mayo:
First, I will confess I NEVER could sharpen a knife on a stone...try as I may...
given that...I would like to say the best.. that is BEST way to finish/polish the edge is with a hard felt wheel on a buffer.
</font>
Click to expand...

Same with me and stones. I just don't have the patience to master holding that angle. Maybe someday.

I resorted to buying a simple bench grinder and using a sharpening "kit" for my machete's. I can actually get a scrapin-shavin' edge (not hair poppin, but skin cell scrapin/shavin) on my 12" to 22" machete's.

And that is at an angle that is at 30 degrees (non-included) too so it isn't terribly delicate. Not a pretty edge mind you, pulling a 22" blade across a wheel involves, well, muscle memory I don't have yet and some art form, so my angle doesn't stay constant. So I haven't tackled the nice big knives, just cheapo machete's (knives from 5" to 9" should be easier than long machetes!)

The "kit" includes two wheels, one to remove metal, the other is a hard, slotted fiberboard wheel and can be seen here, under "Sharpening Equipment, Page 1":
http://www.texasknife.com/store/s-pages/TKS_MainframeStore.htm

Chris Reeve puts the final slightly convex edge on his knives with a hard felt or perhaps buffing wheel, and so does Greg Lightfoot. Both of these guys deliver just outstanding edges on new knives (I'm guessing Tom Mayo does too, just haven't had the pleasure yet!).

Here is Greg's exact response when I asked how he did final edge on his knives:

"I use a 10" contact wheel to start with, using a used 50 grit belt. From there a 220 grit belt, and then a cardboard wheel."
 
You must log in or register to reply here.
Back
Top