Knifeware Knives - Convex Edge Sharpening Instructions

Svashtar

Svashtar

Joined
Dec 28, 2003
Messages
4,793
I have bought a couple of knives off of Ken Warners KNIFEWARE.COM web site, and have been very impressed with them. As you know he is pretty famous in the knife world and really knows his stuff (he now is the distributor for the new Blackjack Knives). With his products he includes a card that says the following:

"We use convex geometry exclusively -- no flat grinds, no hollow grinds, no edges rubbed off. Convex edges stay in any cut better, regardless of the blade profile. They stay sharp longer and are very simple to maintain."

"CARE OF KNIFEWARE'S CONVEX EDGE: To keep it sharp, lay the blade flat on clean cardboard, raise the back of the blade until the edge touches the cardboard, then pull it BACKWARDS, with a firm stroke, the full length of the edge. Repeat on the other side. Alternate strokes until it feels smooth. It will be sharp. A NICKED EDGE needs the same treatment, but on a hard, fine stone, until the nick disappears. Then go back to the cardboard. THAT'S ALL IT TAKES."

"Any other method, except skilled work on a slack-belt grinder or a properly set-up buffer, won't do it. If you have a leather strop, that will work in place of the cardboard, of course."

Interesting. I have every sharpening tool known to man, and he says cardboard is all that's needed! Any thoughts? Anyone ever heard of this technique?

He obviously knows what he is talking about, as the knives he sells have fantastic convex edges, and I have already been bitten once pretty good just from handling one of the knives a bit carelessly.

I also have some info on a sheath they are offering that would be perfect for several HI products, but that will be in a seperate thread.

Regards,

Norm
 
This is an idea that begs experimenting.

A Japanese Santoku should be a good test bed. If the plain cardboard doesn't feel exactly right I imagine a little green chromium oxide rouge rubbed on the cardboard would help.

I wonder what grade of cardboard he uses?

If anyone finds out please tell.

A google search of words "cardboard sharpening" yielded good results.

"A safer and more effective trick is to use cardboard (say, the cardboard back of a standard notepad). You can optionally charge the cardboard with metal polish, just rub it in with your fingers. Then strop as above. Even without the polish, the cardboard will strop acceptably. Stropping with cardboard has become a de-facto standard last step for sharpening chisel-ground (single-side ground) knives these days, for burr removal purposes."
http://www.knifecenter.com/knifecenter/sharpen/instruct3.html

http://www.oldjimbo.com/survival/valiant5.html
 
What a coincidence!

I was just going to announce a new line of the newest technology sharpening devices...the "Cardboard Commando". They are custom made to fit *your* knife and warrented against breakage for life.

Order now...just $129.00 including shipping.
 
Nasty said:
What a coincidence!

I was just going to announce a new line of the newest technology sharpening devices...the "Cardboard Commando". They are custom made to fit *your* knife and warrented against breakage for life.

Order now...just $129.00 including shipping.
Click to expand...

I'll take two. Paypal sent. :D
 
clearblue said:
I wonder what grade of cardboard he uses?

If anyone finds out please tell.
Click to expand...

I've watched Ken touch up the edge of his knife, when he sets up at the local gun shows. He just uses corrugated cardboard that he's flattened.
 
Bruise - Take it in trade for the Utility Kilt/Life Preserver made of bubble-wrap you're making for me!

ps: If you throw in one of your "Liteweight Underwear Paper Scabbards", I'll send you the "Multi-fit" set of 3 *THREE* "Cardboard Commandos"
 
The designer of most of Mr. Warner's knives and the original creative talent at Blackjack is Mike Stewart. He now operates Bark River Knife and Tool and has a forum at KnifeForums. The topic of sharpening convexed blades has naturally received a lot of attention there, as it has here. A search of "convex" and "sharpen" or "sharpening" at either forum will yield a load of information. Try searching "mouse" (for mousepad method) as well.

Cardboard is quite abrasive due to the grit included. That is why cutting cardboard is the most common test of the ability of a blade to hold an edge in cutting.
 
Thanks and good stuff!

I'm proud to announce the addition of a new sharening kit...the "Pocket Commando". All the benfits of the regular Cardboard Commando, but in a convienent pocket size for when you just need to touch up your EDC blade at work.

$49.50, shipping included.
 
If you decide to reprofile a flat grind to convex or convex edge, you can stop at 2000 grit. After that is mostly polishing or same as stropping.
A used piece of 2000 is, voila, close enough to cardboard grit. So if the blade is kept sharpened after each use, cardboard is ok. Though 2000 will do it a bit faster.
Drop to 1600 or below and you will need to go back to using a mouse pad or soft surface to keep the convex shape.
So cardboard, when the knife just needs touching up is fine.
Good question is, what grit is glass?
Rad
 
silica sand dust is so common in the environment
that almost anything could serve as a strop
Yvsa noted once that our skin has effective grit about 5000
I think likely due to environmental silica dust

plants including trees get tiny bit silica dust incorporated in tissues
some plants like horsetails/scouring rushes
en.wikipedia.org/wiki/Horsetail
contain a lot

Some varieties of these were used in japan as sandpaper.
www.scnf.org/saya.html
Shiagekezuri & Shiagemigaki: Finish Planing & Finish Polishing-- .......... The final step involves polishing the wood with ibota powder which is rubbed into the wood surface with pieces of tokusa (horsetail reed). This combination of materials provides a finer polish than any sandpaper could. ......"

Also of interest (re abrasive dust in the environment)
is that there is a huge volume of
micrometeorite dust in the environment.
either metallic iron/nickel or stony silicates
www.solarviews.com/eng/edu/micromet.htm
home.houston.rr.com/molerat/met.htm

Ain't creation cool
 
Nice DDean.
So..there go then Nasty :)
"Pocket Commando"
Click to expand...
The deluxe kit. A piece of cardboard, a square of glass, a used piece of 2000 grit, and a small piece of silica (a broken tri-sharp rod).
All actually work well for touch up.
Rad
 
Hey there Rad...I have a patent pending on that...it'll the "Y2K Survival Sharpening System"

On sale soon for just $1,208.25 (I anticipate a large government order)
 
Seriously...I use my Delta for re-profiling and a razor edge, but after that, a steel, a diamond plate and a 10" piece of old leather belt with some rouge worked into it. Fits in a pocket and cheap enough to lose.
 
Nasty,
I agree. Is nice to have the hi-tech stuff for home, but when outnabout simple, easy, n cheap works best. For me is a DMT bi-fold.

oh,
"Y2K Survival Sharpening System"
Click to expand...
Mil-Spec on that? :p

Rad
 
Svashtar,
I totally agree with what Ken says. I slack belt grind my knives for a convex grind and everything he says in correct. I have not tried the cardboard yet as I recommend stropping on leather with a compound. I feel the blades are stronger, stay sharper longer and are easy to maintain.
Scott
 
Cardboard is as good an abrasive as any. I sharpened exacto knives on it for years when I was a doing paste-up. The main reason I used it was because it was there. No mess, no fuss. Strop just like the barber does his razor.I used the same exacto blade for months, when others were changing them every few minutes. :confused:
 
ddean said:
silica sand dust is so common in the environment
that almost anything could serve as a strop
Yvsa noted once that our skin has effective grit about 5000
I think likely due to environmental silica dust
Click to expand...

So... if I want to abrade metal faster all I have to do is stop washing for a few days. Yes?
 
BruiseLeee said:
So... if I want to abrade metal faster all I have to do is stop washing for a few days. Yes?
Click to expand...
And if you go roll in the mud,
even faster.

;)
 
BruiseLeee said:
So... if I want to abrade metal faster all I have to do is stop washing for a few days. Yes?
Click to expand...

I'd try that Bruise...but most folks say that I'm already abrasive enough. :confused:
 
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