Life Span of Different Knives?

[wildstar]

I was reading up a few articles and browsing through old posts and started thinking about different knife geometries, steel, and other factors that might limit the amount you can sharpen a knife. For example, I believe convex blades require a belt sander and experienced hands to resharpen - so I could never really resharpen them because my skill is in sharpening flat grids with a regular stone. I read on AG Russell's site that hollow grinds are easy to sharpen at first but as you continue to sharpen over time, it becomes more difficult. The reason for all this research was that I was thinking of getting a Fallkniven blade but read a few posts about the difficulties of sharpening a convex blade.

I have sharpen my 15 (or 20) year old SAK over the years and it does not seem to be as sharp when I work on it than my newer SAKs. My newer SAKS with resharpening can come out really scary. I have only sharpen my CRKT M16 and Spyderco about 3 to 4 times and they still seem to come out quite sharp.

So with time, will certain blade blade geometries or steel become for difficult to resharpen?

Any type of blade geometries or steel to avoid for the average person with average knife sharpening skils to avoid? I like to keep my knives for a long time and not just buy new knives as they come up - too poor!

 

[Sword and Shield]

You might need to thin your SAK again. Try honing at a thinner angle for a while, and the cutting ability will come right back.

 

[Kazeryu]

convex grinds are fairly easy to resharpen. A belt sander just shortens the job down to about five minutes from start to finish.

There's a number of threads about it over in the HI forum if you want to do a search, but here's the basic recipe:

You'll Need:
1 thick rubbery mousepad (or even a pile of folded denim in a pinch)
200 (for serious re-work), 400, 600, and 800 (or higher if you want) grit sandpaper


1) lay the sandpaper on top of the mousepad and hold it firmly. (you may prefer to glue the mousepad to a piece of wood first)

2) using firm pressure, sand the knife against the grain of the metal. You'll want to lay the entire convex bevel flat against the mousepad when sanding. You'll find that the rubbery mousepad backing under your sandpaper forms itself to the existing convex bevel -
caution! if you put too much pressure on, you'll increase the included angle of the final edge, so adjust accordingly.


As normal, form a nice burr on one side, switch to the other side, and then go to the next higher grit and repeat.

3) strop along the grain of the metal to polish the edge and take the final burr off.

4) SLICE!

You can also use this method to put a convex edge on a flat ground knife. Adjust your pressure on the mousepad to get the bevel curved the way you want it.

There are some videos done by Daniel Koster which show how to sharpen a khukuri in this manner - they're still available for download if you send me an email.

If you want to practice this method before trying it on one of your fancier knives, just buy an Opinel and sharpen away.

Hope that helps a bit!
-Ross