Pen's 15" AK convex vs. 15" AK flat grind by me....

[BruiseLeee]

The mailman arrived on Tuesday morning with a box. I knew it was the 15" Ak because I could see the chappe sticking out of it. No damage though and it was still covered in plastic. I quickly ripped open the box and looked intently at the pages from the Washington post. For some reason I like skimming foreign newspapers. It's a treat to get the front page. I got a Walgrens flyer from Uncle Bill once... Goobers were on sale, but I digress (digest?)

After putting down the newspapers I tried the same tests as on Pen's videos. It worked as advertised. However, I couldn't get it to push cut with the edge always perpendicular to the paper which is how I thought it was done. Not that my edges could do it either but just my perception.

General appearance.

Pen polished the horn with "Briwax" and gave the steel a satin finish. Nice shiny handles I didn't do the karda tests like the video though. Convexing the blade took the edge back about 3/16" I would guess. This gives the overall profile of a BAS. I suppose convexing a BAS will make it look like a sirupati. Convexing a sirupati might make it look like a bent toothpick.

The fit of the sheath due to less edge was loose. It stays in place from friction at the bolster. I like this. The blade can be resheathed with little effort.

Slicing Paper

The convex edge sliced paper smoothly throughout the edge. Compared to mine, the convex edge took less effort. Not by much but it was noticeable. The convex edge wouldn't slice paper on really shallow angles though because the sides of the blade start to get in the way. Not a huge difference, maybe 5 degrees or so. Not a big deal unless you like making paper ribbons.

Mangling Cardboard

Next was to cut up the box that Pen shipped the knife in. Again Pen's AK required less effort to cut through the box.

Shaving

Since I was sitting on the floor, I took the oppurtunity to shave part of my leg. Both shaved but again the convex edge was sharper.

Enough goofy tests. The blade sharpened by Pen was sharper than the one by me. Then I cut stuff and it was good.

Brush

I found no difference in the two when cutting light brush. However, while cutting brush with thorns a longer blade would be preferable. I was still digging stuff out of my skin this morning. There wasn't too much difference cutting limbs (wood). After a few minutes of cutting with each the convex edge still shaved as it had when it came out of the box. Mine still shaved but only after turning the skin red. I think I scraped enough skin away that the hairs just fell out.

The real difference was seen when cutting a log. The convex edge tended to push the wood outwards, breaking pieces off (wood) instead of me having to cut at the opposite angle in order to release the chips. Even with the flat grind I've never had a problem with the blade getting stuck in the wood.

Looking at the edge there is a lot more metal closer to the cutting edge than there is with my flat grind. I think this would be more evident in a larger blade where the force and torque on the blade is greater than on a 15" blade.

I haven't really had a chance to go through the video in detail yet. However, by playing with the convex edge it's something I figure worth learning how to do.

Thanks again to Pendentive for sharpening the AK and making the video.

(all spelling and grammatical errors were intentional)

:yawn:

 

[Yvsa]

Tol' ya so.

Nice review Bruise. I don't think anyone was aware that you had achieved the shaving edge as yet.
I sure wasn't. Congratulations!!!! Now you can look forward to achieving the convex edge and Nirvana.

 

[Mr.BadExample]

Great review, Bruise!
I've managed to get shaving sharp edges on my 18" Chit and the 10" new model. The choppers have working edges. Nothing is as sharp as my convex AK Bowie with Pen's convex edge though!

 

[Red]

Thanks Bruise, I'll have to look into some strops.

 

[The Big Kahuna]

That was really helpful, Bruise (and I thought he only made funny noises all the time)

I've been too afraid of ruining the edges of my khukhuris to try "convex sharpening" them. So I've been practicing on cheaper blades with lousy results (they seem to get duller ).

But I just got an Svord economy pig sticker made by Bryan Baker from New Zealand (by the way for US$50 for a 7" blade handmade knife, it's a great value; his usual range is priced in the hundreds; I think he had demand in NZ from hunters and farmers for an economy user range - same blades and edges but finish is straight from the forge and handles are very basic). This one had that legendary full convex edge that the old wise men in this forum preach about. My arm hairs just floated off the blade. It could cut paper strips less than a millimeter wide just by drifting the paper egde along the blade.

Anyway it inspired me to try "convex sharpening" the karda of my GS (the smaller it is, the sharper it has to be!). Followed the FAQ and suggestions on the forum to a "T". Put some 600 grit sandpaper on a velcro backed wood slat. Was careful not to flick the knife toward the perpendicular at the end of the stroke. Stroked each side until I could feel the "edge burr" on the opposite side. The went to the slat's other side which had a leather strip on it with green chormium oxide rubbed in. Did the same thing until I could feel the "edge burr" again.

Dang-ed amazing! It wasn't as sharp as the Svord. But the karda could shave my arm hairs if I pressed it against the skin a bit. And it could cut those thin paper strips (a few millimeters thick) with a tad of effort! This really works!

My thanks to all on the Forum for the education. And yup, when I'm back in Hawaii I'm gonna see if I can get one of those leather belt "knife sharpening" machines.

 

[ddean]

Originally posted by BruiseLeee .....I cut stuff and it was good.

And thus the 'Way-of-the-Khuk' came upon us.