Rube Goldberg sharpening

[firkin]

Thought this might be useful to those still learning to sharpen convex edges or sharpening maniacs who want to try new things.


While somewhat absently mindedly rubbing the side of the blade of a folder on my mousepad while waiting for a site to load, I recalled Cliff Stamp's mention of grinding a convex edge with carborundum paper laid down on styrofoam, and using a stropping stroke. How about the mousepad?? Seems a little firmer, should last longer and not permantly compress. I searched BladeForum to see what other tricks might be found, and dscovered that my "invention" had been invented previously by several other people. (Like most "inventions"!)

Here's a couple of links to other, prior threads:

http://www.bladeforums.com/forums/showthread.php?s=&threadid=176756&perpage=20&highlight=mouse pad convex&pagenumber=2

http://www.bladeforums.com/forums/showthread.php?s=&threadid=182200&highlight=mouse+pad+convex

Anyway, I easily reshaped the edge on a diving knife using the mousepad under 400/600/1500 grit paper progression to get a convex edge. I then did a final honing with the green chromium oxide honing compound that comes as a stick (locally available at a wood-working store) applied to very thick watercolor paper, again with the mousepad underneath. Works great. I then tried it on a karda that still had a couple of dull, thick spots on the edge. Again, worked very well. I was able to work the entire bevel (1/2 blade width) and raise a complete burr using the sandpaper if I pushed a little . Progressively lightening the pressure, and working up to the honing compound provided a polished shaving edge with no dull spots.

Haven't tried this on a khuk blade yet, since that had a fairly reasonable edge upon arrival. Something longer to replace the mousepad and a section of a sanding belt to replace the sheet of sandpaper could work better for larger blades though. The watercolor paper comes in several degrees of roughness: rough (maybe too rough), cold-pressed (which I used), and hot-press. The hot press is probably pretty close to smooth leather. 18x24 sheets of this type of paper are often available singly at good art stores for a couple of bucks and would provide several strips. This is strong, thick paper, about nearly the thickness of a paper tablet back and should last a while. No worries about cutting up a leather strop while learning and one could experiment with lots of different abrasives. Stick to oil-based mediums, the paper will stretch when wet, and buckle as it dries.

Obviously, knowing what you are doing and ordering leather strop materal from HandAmerica is the deluxe way to go on the stropping.

OT note on viruses:

If you think HIKV is bad, the guys with the Syperco Sharpmaker virus are really afflicted. Some people seem immune, or mildly affected, but the severe cases are really bad. They want to use it sharpen EVERYTHING. One of them is probably trying to think of way to use one to sharpen his wits.

 

[Yvsa]

Way to go Firkin!!!!!!!

I keep telling everyone that the convex edge is really easy to sharpen and IMO to anyone never taught the so called "proper way" of sharpening the convex edge will come naturally.
Seems that you have ran across a really simple way producing the edge you want.

You can splice sandpaper by overlapping it about 1/4" or 3/8" using a spray glue to keep it in place. The only problem is that you have to use what you've set up to sharpen with in only one direction.

As far as wits go around here in the Cantina it was determined long ago that if there were any two of us together at any one time then we would have what is, or could be, classified as a full wit.

 

[Bill Martino]

Good stuff and good humor.

 

[firkin]

Yvsa,

I DID have to unlearn the "proper" way of sharpening. Unlearning was a hell of a lot easier than learning. Like 20 minutes vs. years.

Well, that's not quite true, I did learn how to properly sharpen a thin-bladed double bit axe with a file long ago. But not to as fine an edge.

But for heavy-use blades, convex has to be the best, espcially for chopping.

I think I will still use a single flat bevel (on both sides) for thin bladed knives. But my thick-bladed kitchen cleaver is next for conversion. It will be a bit of a chore-- the karda was already ground, and the thick diving knife was concave ground, so I really only worked the bevel. But the new convex bevel on the diving knife should be stronger. The most important part of the diving knife is the saw edge on the back and line-cutting hook. I occoasionally snorkel and free dive, no tanks, and I think that a knife is even more important for this application than SCUBA. Most non-scuba people don't carry one. Seeing a couple tangles of large monfilament fishing line underwater when I was a kid converted me. Can't untangle much holding your breath. When I was kid, we carried Ginsu kitchen knives in garden hose sheaths.

You can splice sandpaper by overlapping it about 1/4" or 3/8" using a spray glue to keep it in place. The only problem is that you have to use what you've set up to sharpen with in only one direction.

Sounds, good...dunno about splicing mousepads tho. Need to think up a cheap, commonly available similar thing.

As far as wits go around here in the Cantina it was determined long ago that if there were any two of us together at any one time then we would have what is, or could be, classified as a full wit.

Well, OK... My comment was directed to a maniacal class of sharpmaker users elsewhere that were wrapping the rods with leather or mousepads, and then wrapping them again in sandpaper. It's apparently inconceivable for these guys to use even a steel freehand.....whew!

 

[Bill Martino]

Whew!!!!!!!!!!!