Getting Another BK21 (Dyed Strap)

91bravo said:
You can, but it takes quite a few sharpening sessions to get there.
Click to expand...
No, can you, haha.
daizee said:
Sure, you can convex anything. There are two strategies:

1) sharpen at a "normal" angle (~20dps in this case) and then roll the edge shoulder back to reduce drag
2) sharpen at a shallower angle (~15dps?) and then roll the edge itself a smidge steeper for more strength at the weakest point

You can do both of these things at once with the sandpaper-on-a-mousepad trick if you want to be aggressive. For convex sharpening, I like to use the $3 soft-core 3-sided nail buffing pads from the drug store. But they don't have enough abrasive to remove a lot of material.

The typical issue with recurves is that rectangular sharpening "stones" only contact the inner curve at two corner points. If you have a rounded-over natural stone that you don't mind making rounder, that can work ok. But if you're using something like a diamond plate it really doesn't work at all.

An ovoid or round diamond rod connects tangentially with the edge vs. at two points, so you get around that problem.
Of course a standard kitchen steel will work to dress the edge just like on a kitchen knife, but certainly won't be aggressive for ACTUAL sharpening that requires removing material.

My armchair suspicion is that the Fisk'd blade was just sharpened better overall, and it wasn't the convexing specifically that was the secret sauce. I mean... a master bladesmith spent a few minutes on ONLY the edge of ONLY that knife - results should be excellent.

I've generally found my Ka-Bar non-recurve edges to be perfectly adequate out of the box. Maybe a wipe on a kitchen steel or a quick strop would be a mild improvement, but they're usually fine. What I'd produce by hand? No. But meeting expectations for a big, mass-produced blade at the price point? Absolutely.
Click to expand...
Some good info daizee, thanks. My problem is, I can't even sharpen a straight blade, much less a recurve. I know practice is key, but I'd hate to mess my new 21 up trying to convex it.
 
Took my own BK-21 over to the ship to warm up the new diamond rod.
Here it is in the vise, but ultimately I picked it up in my left hand and went at it totally free-hand. For setting an initial edge I'd keep it in the vise.

Note the chatter in the recurve area of the edge bevel - that's factory tool marks. Maybe a rigid stone/wheel that sets the edges?

The rod did a good job of cleaning it up, but the diamond dust just cascaded everywhere. Looks like it's scraping right off the rod. This can't be right. Normally diamond "stones" do have a weird quick wear period before they settle in, but this is... concerning. Guess I'll have to use it more and find out. If it wears badly, back it goes and I'll use another tool for Tank's project.

IMG_20220310_190153-small.jpg


IMG_20220310_190224-small.jpg


IMG_20220310_190809-small.jpg
 
daizee said:
Took my own BK-21 over to the ship to warm up the new diamond rod.
Here it is in the vise, but ultimately I picked it up in my left hand and went at it totally free-hand. For setting an initial edge I'd keep it in the vise.

Note the chatter in the recurve area of the edge bevel - that's factory tool marks. Maybe a rigid stone/wheel that sets the edges?

The rod did a good job of cleaning it up, but the diamond dust just cascaded everywhere. Looks like it's scraping right off the rod. This can't be right. Normally diamond "stones" do have a weird quick wear period before they settle in, but this is... concerning. Guess I'll have to use it more and find out. If it wears badly, back it goes and I'll use another tool for Tank's project.

IMG_20220310_190153-small.jpg


IMG_20220310_190224-small.jpg


IMG_20220310_190809-small.jpg
Click to expand...
Looking good. I’m still figuring it out on my end
 
You must log in or register to reply here.
Back
Top