Katana sharpening

[Luis G.]

Should I choose to do a job like this using sandpaper, what grade of sandpaper do I need and what grits should I start with and progress up to if I want to reach a martial arts polish? I don't really think I need to make the sword shine like a mirror, but I would prefer not to have to do this again for a while.......

Use 3M Sandpaper seems to give the best results and is easily available at Wally world, and better yet Autozone. Considering the sword I'd recommend 220 as the lowest just to apex the edge (will happen fairly quickly). Then move to 400 grit to begin putting a vertical the scratch pattern. Begin cross polishing at 800, then 1000. That will suffice.
Quite frankly a martial arts polish in today's terms means nothing more than sharpening the edge and perhaps roughly refinishing of the ha. Edge/niku geometry is often lost, or utterly destroyed.

Your goal as you are starting is to just get the edge to apex. Don't worry about the cosmetics.

PS: Forgot to mention. Following traditional methods are best. Sit on the floor with an elevated stone. I know what I am telling you.

 

[greensngravy]

Read up on various problems with using machine techniques for sharpening and polishing a katana. I bought my first katana, a Shinwa damascus Wakizashi. Beautiful sword. But I have no business sharpening this with the traditional water stone methods yet as I have zero skill and patience. My decision was to acknowledge that if I used the stones I would really ruin the blade by completely messing with the edge geometry.

Question from an insensitive newbie: Why are we so concerned about changing the edge geometry of a Katana from the "apple seed" to the "V" if the "V" actually cuts just as well???? Does it have anything to do with angering the Shiinto gods? My sword will never be worth more than the $65 I paid for it, and spending hours to sharpen ot does not fit into my lifestyle (until I retire!)

Your thoughts? And let the games begin...

 

[horseclover]

My sword will never be worth more than the $65 I paid for it, and spending hours to sharpen ot does not fit into my lifestyle (until I retire!)

Your thoughts? And let the games begin...

Welcome aboard

Considering the price point, it is senseless to even suggest altering the sword from how you received it will matter much. Beauty and value are quite subjective. The next sub $100 sword I am looking at is about 225 years old. No doubt that I will be fiddling with the blade some. The only gods I am going to anger are other antique collectors that didn't spot it.

The cutting performance of a blade with a very convex cross section will suffer if an acute and wide secondary bevel is added. A micro bevel on such a blade doesn't have much effect to the overall cross section. If any secondary edge is kept close to the angle of the cross section, it is really just an aesthetic that could be polished out to match the rest of the blade and all but visually disappear. Some finish an edge using fine grit paper (I have done this with ceramic blades).

A zero edge on either a convex or flat grind will suffer some if another more acute angled edged is added. An exception is a hollow grind, where the edge itself is actually part of the overall cross section.

Consider a cold chisel for breaking/cutting a steel bolt vs a single edge box cutter blade used to cut cardboard.

Grind away!

GC