What Angle to sharpen Benchmades?

S

SanShou

Joined
Nov 18, 2005
Messages
258
Hi!!
I'm stillo a newbe at sharpening and actually got a Shaprmaker (I have really improved with it thanks to this forum) and a Lansky pro. I have no problem sharpening most of my knives but I can't get the sharpnees I'd like to with most of my Benchmades.

Recently I got a 14210 that came sharp but no shaving sharp form factory and I'd like to improve the edge a little bit, I tried with my sharpmaker at 40º but I don't think I'm sharpening at all. I know that's because It probably has a wider angle but my question is...

What do you do when you face something like that with your sharpmaker?
Are all the BM's wider than 40º from factory?

Thanks!
 
Some of them are, or they are uneven, it could be 25 on one side and 15 on the other, so you will never remove the burr that forms. There are two ways to deal with this, grind off the thicker angle or just increase the sharpening angle to match the initial profile. In general it takes extreme use to require more than 15 degrees per side and you are much better off taking an x-coarse hone and reducing the angle to 15 and then sharpening with the Sharpmaker at 20. As time passes you might find that you are better suited to a more acute profile still and will break out the x-coarse hone again and now move the bevel down to 10 and then sharpen with the Sharpmaker at 15.

-Cliff
 
Thanks a lot Cliff! So you recomend me to get the Sharpmaker Diamond Stones? I don't why but I'm not that confortable sharpening with my Lansky as when I do it with the Sharpmaker... I suppose that reprofiling with the sharpmaker using the grey stones is a loooooooong way to go...
 
Unless you are concerned with looks, you don't need to buy diamond rods. I bought a 1inch x 4.5 inch coarse diamond stone from the hardware store for 12 bucks. A coarse or combination aluminum stone will be not even that. Both of these should be faster than the diamond rod.

I feel I have more control taking off that much material not using angled rods.

If I see a scratched up production knife with the angled taken down 10 degrees per side, I would think more of the owner than a pristine one at 20+ degrees.
 
SanShou said:
So you recomend me to get the Sharpmaker Diamond Stones?
Click to expand...

I would not use it for reprofiling, but they would be useful as grit choices for slicing abrasive material. For reshaping you don't need precision, unless of course you care what the knife looks like anyway. But once you start thinking about performance that sort of gets ignored and knives which are heavily used are full of scratches anyway. Some people will lean the stones alongside the Sharpmaker, or wrap the sticks in coarse sandpaper. All of these will work, but are slow compared to freehand honing.

kel_aa said:
A coarse or combination aluminum stone will be not even that.
Click to expand...

You can buy really cheap ones for $2 locally. They work well on the steels which are easy to grind, but the don't break down well and are radically outperformed by coarse waterstones on steels like S30V. I have seen a number of cheap hardware store hones what work really well though, usually called axe or lawnmower hones. They break down fast and cut really well. You can pick up them up easily at flea markets for cents. They are usually heavily loaded, but that isn't a serious problem. About the fastest freehand honing I have seen is a 80/100 aluminum oxide sanding belt glued to a piece of hardwood and used like a file, that is actually capable of adjusting primary grinds in a reasonable about of time.

-Cliff
 
The secret is to get that black magic marker out of the drawer and mark the bottom edge of the knife. When you sharpen, at whatever angle you decide, the black should be removed the the very bottom of the edge. If not you are not sharpening at the edge but just removing steel somewhere else on the blade.

http://forums.egullet.com/index.php?showtopic=26036

Most sharpening methods result in a double-bevel edge. The big secondary bevel and the tiny dinky primary micro-edge bevel. It's that dinky micro bevel you want to sharpen. The above link has some good pictures and diagrams showing the process.

I have used the 40 degree setting successfully on my Benchmades. I rarely reprofile. I use the edge of the gray/brown rod until the edge is very sharp. Then I use the flat of the gray/brown rod until very sharp. The I do the same thing with the white rod. Then I strop/hone with CrO. If the edges or flats load up you just rotate the rod.
 
Yeah the 40 degree setting on the sharpmaker should sharpen benchmades, but as cliff already mentioned benchmades sometiems have one side at a different angle, so you may want to re profile.

I recently did this with my BM 43. I used the spyderco diamond hones at the 30 degree setting, did not take too long. Then I polished with the other two stones. I decided to do a multi bevel because there was some blade damage and at the 30 degree angle I would have had to take a lot more metal off. I used the grey stones to make a second beve, getting ride of most of the damage, and then finished up on the white stones. I had some trouble because I did not polish on side enough and one side seems mildly sharper. There is no burr, it does not reflect light. It shaves extremely well on both sides, just have to touch the blade to hairs to cut them, but one sides seems just a little more aggressive. I then used it later to cut the bottom off a plastic oil container, quickest way to make a funnel, and it was still sharp, so I do not think there was a burr.
 
For most utility knives (which makes up the bulk of my EDC knives) I set the back bevel with the 30 degree slots with the knife tilted slightly to make a bit smaller angle (probably 11 to 13 per side). Then with the same tilt (or there abouts) I use the 40 degree setting for the primary cutting edge (17 to 19).

My 154cm BM710 seems to respond well to this. Some knives I'll go higher or lower. With an angle guide and height adjustment screws (or magazines under the edges of the Sharpmaker) you can set just about any angle you want.
 
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