Convex Edge Sharpening Kit

[StretchNM]

I know there are alot of Bark River knife owners out there, and also owners of convex-ground Falknivvens, Cold Steels, and others. There are always recurring questions on convex edges.....So... thought I would post some pictures of my updated convex edge grinding setup.

In the pictures below, each board is approximately 2-5/8" x 11 x 1/2", and they're covered with 7-8oz leather glued on with contact cement (yellow glue clamped would work just as well). I get my wet/dry from a variety of sources, including auto parts stores, and usually go to the woodworking store for 1500 and 2000.

I do not claim to be an expert, but using this setup, I've been able to get (better than) excellent results on my Barkie's edges. Maybe this will help some guys:

and this is with the boards flipped over, showing the other sides:

These links are pretty good primers on convex edge sharpening:
http://www.barkriverknives.com/home.html
http://home.nycap.rr.com/sosak/convex.htm

 

[sketchbag]

Looks good.

I was using a heavy piece of leather on top of a block for my strop before, but I've switched to a thin piece stretched tightly across the block and I've been getting better results. I was having problems with dulling my knives on the thick strop, which I no longer have on this one. Perhaps I'm doing something differently that I'm not aware of, or maybe the the heavy leather was more sensitive to pressure and more easily contoured around the edge causing it to blunt.

Can you tell me more about the red strop on the right?

 

[StretchNM]

It's not really red, Sketchbag, it's just some reddish leather underneath of some of Fellow Forumite Sodak's white compound (Thiers Issard, I think). That compound is a little more gritty or coarse than green CrO2, and I use it on occasion before using the green.

Like the green strop, the white one (or reddish one) has a rough side on the back.

I think this convex edge sharpening has plenty of room for play and experimentation. Each sharpener has to find what works for them, because each one uses different technique in wrist movement and flex, pressure, number of strokes, angle of attack, etc. My system works well for me, but I'm ready to try some new angle of attack. Bring on some ideas! :thumbup:

 

[s.c.]

Thanks for the pics. I just got a Fallkniven S1, so I need to make something like this. Where can you get strips of leather like that? Also, where to get stropping compound?

thanks.

 

[Dog of War]

Nice setup, Stretch. One thing I'm curious about ... do you use the same pressure when sharpening on the different grits, or do you get better results, say, using lighter pressure as you get into the finer grits?

 

[sketchbag]

I find that if your edge is already very thin and youre just polishing it up, you want a very light touch. Too much pressure will make a soft sharpening pad wrap around the edge and dull it, but when I'm reprofiling a flat ground edge into a convex and focusing on the shoulders of the bevel I'll push it down until the edge is just barely hovering over the sand paper. just my 2cents.

 

[StretchNM]

Yes I do lighten up as the grits get finer. On the 2000, there's virtually no pressure.

 

[Dog of War]

I find that if your edge is already very thin and youre just polishing it up, you want a very light touch. Too much pressure will make a soft sharpening pad wrap around the edge and dull it, but when I'm reprofiling a flat ground edge into a convex and focusing on the shoulders of the bevel I'll push it down until the edge is just barely hovering over the sand paper. just my 2cents.

Yes I do lighten up as the grits get finer. On the 2000, there's virtually no pressure.

Thanks guys, that's what I figured, but wanted to confirm it with the convex sharpening experts. IMO this issue of pressure often goes unmentioned in discussions about sharpening, but is key to getting an edge that's really sharp and durable.

 

[Liam Ryan]

Is the CrO the last step? About what grit of paper is it equal to?
I tried using it on some vinyl fake leather for my strop, I am not sure if it's working or not, but I think now I was pressing too hard.

 

[thombrogan]

Nice setup, Stretch! A lot more elegant than my kit consisting of benchstones and a two liter of Diet Coke to get the caffeine flowing.

Thanks for the pics. I just got a Fallkniven S1, so I need to make something like this. Where can you get strips of leather like that? Also, where to get stropping compound?

S.C.,

Look in the yellow pages (libre d'amarillo?) for leather stores. The shop near my place has sold me some belt leather cut to size (I went for 1" x 15" and 3" x 15", but that's overkill) for $3-5 a piece. You can get the official Barker River compounds either directly from them or from resellers. The Thiers-Issard compound can be found at Knifecenter and some shaving supply places (very nice stuff, but very expensive and coarser than the green stuff sold by Bark River, Lee Valley, and Toolsforworkingwood). Stretch's array of wet/dry paper followed by Bark River's black and then green compounds will probably save you a lot of time and sanity.

 

[Zeasor]

...You can get the official Barker River compounds either directly from them or from resellers. The Thiers-Issard compound can be found at Knifecenter and some shaving supply places (very nice stuff, but very expensive and coarser than the green stuff sold by Bark River, Lee Valley, and Toolsforworkingwood)...

1) What is the minimum grit stones/paper you would finish with before progressing to the compounds?

2) Do you have any experience/opinions on the compounds sold at Sears?

 

[thombrogan]

1) What is the minimum grit stones/paper you would finish with before progressing to the compounds?

2) Do you have any experience/opinions on the compounds sold at Sears?

1. 2,000 for each. Though, technically, I use lapping film and polishing paper instead of compounds, so it's not like I ever really get away from the sandpaper.

2. None. Bought mine from Home Depot, Spartan Buff Company, Rocklers, Knifecenter, toolsforworkingwood, and bought some 0.7 micron and 1.8 micron boron carbide from ESK/Ceradyne and HandAmerican to "roll my own."

 

[Zeasor]

1. 2,000 for each. Though, technically, I use lapping film and polishing paper instead of compounds, so it's not like I ever really get away from the sandpaper....

Thanks for the help.

...2. None. Bought mine from Home Depot, Spartan Buff Company, Rocklers, Knifecenter, toolsforworkingwood, and bought some 0.7 micron and 1.8 micron boron carbide from ESK/Ceradyne and HandAmerican to "roll my own."

Wow! The lengths you go for an "edge" or a tinker's "high". How do you keep them lit?

 

[thombrogan]

How do you keep them lit?

Thinly-ground edges with high-hardness/low carbide volume steels.

If you notice that Bark River's knives are mostly A2 tool steel and 12C27 cutlery steel ran at about RC60 and leave the factory with very thin edges, you'll see lots of people like that same high.

Actually, from the knives I like to the knives Stewart makes (knives I like, but don't have) to the straight-razors of extralegal personnel procurement specialists, there seems to be some overlap between pushers and push-cutting blades. Please check your PM box.

 

[StretchNM]

Is the CrO the last step? About what grit of paper is it equal to?
I tried using it on some vinyl fake leather for my strop, I am not sure if it's working or not, but I think now I was pressing too hard.

Liam, the CrO2 is the last step, for me anyways. I'm thinking that it's equivalent to about .5 micron, but if that's correct, I don;t know how to translate that into sandpaper grit.