Bevel angles for softer steels

C

Clang!

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Jul 26, 2010
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First post here. I've got a couple of Arkansas stones that came off their bases. I'm thinking about mounting them onto angled blocks like below. (Illustration from RokJok post).
stone-jig.jpg


The knives are a couple of SAKs (420) for EDC, an older Buck Crosslock (425M) for medium duty, and a S&W Extreme Ops Bullseye (440, probably "A") for use and abuse.

What angles should I use? I'm considering 20 deg for the course stone and 25 for the medium stone.
Are the angles inclusive or measured off of the plane of the blade?

Thanks,
Clang!
 
May I suggest an adjustable base?

I made one that is adjustable and rather than holding the knife as you show, I hold the knife horizontally (which I like when I want to use water on the stones because the water does not run off letting the stone dry as fast).

Here is a link to the video if you are interested

http://www.youtube.com/user/ewerstruly#p/c/299E614F6D3C94DD/6/AXhrqfV5jvs

There is a lot of discussion for grind angles. It really has a whole lot to do with how you use the knife. Many HARD use knives will be ground at 20 or 22.5 per side while a lot of pocket folders will use 15 per side...recently I have been using 10 per side on VG-10 with good results, but I enjoy sharpening frequently;)

I suggest (for a lot of guys) to use the same grind angle for all stones, and perhaps taking a few (2-3) passes on the last (finest) stone at a slightly larger angle to put on a micro bevel.
 
I use 12 degrees and 17 degrees in the same vertical configuration you do, then add microbevels with the Sharpmaker at 15 or 20 degrees. I haven't run into any steels that won't hold the 20 degree edge. The 12/15 has trouble on softer steels. 20 and 25 sound good to start. If you're making them yourself, just make a 15 if the first 2 dont work out. I use scrap 4x4 and 1x6 wood, and my table saw has an accurate way to cut angles. Realistically, any angle in that 20 to 25 range should work. These just help with repeatability.
 
unit said:
May I suggest an adjustable base?

Here is a link to the video if you are interested

http://www.youtube.com/user/ewerstruly#p/c/299E614F6D3C94DD/6/AXhrqfV5jvs
Click to expand...

That adjustable jig is a real elegant solution. I'm think I'm going to build one based on it.

me2 said:
I haven't run into any steels that won't hold the 20 degree edge. The 12/15 has trouble on softer steels
Click to expand...

Since the steels are all around 56HRC, I'll probably make my first setting 20 & 25 deg.
 
Steel has to be pretty soft for it to not take an angle of 10 degrees, inclusive. In fact, that seems to be the best way to deal with soft steel such as 420J2. Make it thin and really acute. I did this recently with a Kershaw carabiner knife made from that stuff, a mediocre cutter until the stock blade was reprofiled to a full flat grind with a zero edge. Made sure the edge steel was sound, and then power strop it to usefulness. The improvement was like night and day.

I've given similar treatment to other knives with such steel. It's always an improvement. The only way I'd ever go to a 20 degree sharpening angle would be if the edge bevel was already at zero, or damn near.
 
I have an Old Hickory 7" butcher that original came with a saber grind with a rather thick secondary edge. I gave it a zero degree edge and a micro bevel. A great light chopping knife now. I can chop all afternoon and don't notice any edge deformation. Old Hickories are suppose to be pretty soft, around 54rc? I think people underestimate soft steels.
 
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