Sharpening my Ka-Bar USMC Fighting Knife

[cziv]

Anyone got an idea of the bevel on a USMC fighting knife. And, how far can it be laid back to?

I have mine at a mirror polish but the obtuse or wide bevel still causes it to bust up copy paper when slicing if I'm not very careful, in which case it will slice about a 1/2 page and then as it gets deeper in the paper tears. I believe it's the thickness of the blade and perhaps the bevel degrees and not a burr.

Looking for some ideas for an optimal edge angle "XY*" to shoot for - microbeveling, whatever.

 

[Jason B.]

As a standard I shoot for 15 per side. You can go as low as you want even scandi if you like, but how well its going to hold up will be the question.

If you are using a jig the paper slicing thing might not improve because of the edge geometry.

 

[cziv]

As a standard I shoot for 15 per side. You can go as low as you want even scandi if you like, but how well its going to hold up will be the question.

If you are using a jig the paper slicing thing might not improve because of the edge geometry.

So you don't think 30* is too thin for a fighting "semi-hard use" Ka Bar? What about a 40/over microbevel?

The paper slicing thing is no big deal. I do that as many of us do to check sharpness. It only came to my attention because I have it down to a mirror edge now. I had expected it to slice better than that. Heck, my big old Junglas will sing through printer paper. Just sayin..

I sharpened this one on DMT benchstones and finished it with the Spyderco 8"x3" UF stone, then stropped. No jig.

I could touch up with my magna-guides for a micro bevel. I want it to be tough enough for survival use but still be a good cutter for making a debris shelter and multi-purpose where a very sharp knife could save a person a lot of time. Just not sure how to proceed

Maybe my apex isn't complete (both sides meeting) even though the edge is mirrored. It passes the thumbnail snag test but I didn't do it along the whole cutting surface.

Any more guys?

 

[Ben Dover]

Personally, I would be happy with the K-Bar. This is a fighting/survival knife. The blade is thick and heavy, the steel and heat treatment are engineered for "hard use," rather than precise, delicate slicing.

Enjoy your K-Bar as an outdoor knife, and if you want a pushcutter, get a knife with a thinner, lighter blade, made from a harder steel, and designed with a different blade geometry.

Just getting a K-Bar to 15 degrees, and highly polished is quite an accomplishment in and of itself.

I appreciate a challenge, as you obviously do, but in this case, I truly believe that you've come up against the limit of blade geometry.

 

[Jason B.]

Try leaving it at the EF hone with just a light strop on bare leather after, personally I've never liked 1095 with a high polish.

 

[cziv]

Apreciate your replies. I just got it off the x-fine stone. Still needs a lot of stropping as the new stone isn't broken in & turns a very tiny burr no matter how lightly I try to erase it on the other side - then flip and erase then flip and erase......repeat ......repeat......repeat

I convexed my 3 Izulas to a mirror finish and they are awesome little cutters and tough too. They go through wire, hardwood, prying lightly with the tip & they sizzle through paper, newspaper. Very sharp, Rowen does a hell of a job on them. :thumbup:

 

[Jason B.]

Funny you say that because I was originally going to write I only like 1095 at a high polish for convex or on choppers. The higher grit edge finish plus convex geometry mesh well together.

 

[Obsessed with Edges]

Funny you say that because I was originally going to write I only like 1095 at a high polish for convex or on choppers. The higher grit edge finish plus convex geometry mesh well together.

That sounds right to me.

I have an old leather-handled Western L48A fixed blade in carbon steel that I convexed a while back, using wet/dry paper. Finished it to ~2000+ grit. I hadn't anticipated it, but found that this combination worked really well when I tested it by slicing into a phone book. Went deep, and with very little 'grunt' applied. Convex really excels on a thicker fixed blade like that. Also does quite well slicing individual pages from that phone book.

 

[cziv]

Well I got my Ka-Bar all finished last night. My mirror edge that tor paper was done with guided shaprening (DMT Magna-Guides). I've been breaking in my DMT bench stones and it just didn't do as good of a job as the broken in dia-folds although it only took about an hour as compared to several hrs. when I mirrored it with the system.

Stropped her all out and lost my mirror edge partially, left a lot of sparklies because of mistakes ie. newbie stuff like grit changing too fast and such. The front of the knife is mirrored and pretty the back is kinda scritchy scratchy - but all sharp.

So, before putting it away I did the same sharpness cuts on paper and after all of that work I ended up with a few unsightly scratches in the black coating (not to the metal) and the darn thing (lovingly hand honed) wasn't a damn bit sharped and tears paper about 4 - 5 inches into a sheet.

SHE'S A USER ALRIGHT!!

 

[Komitadjie]

My default reaction would be to take 'er to the belt and convex that sucker. Which is precisely what I did to mine, actually. I'm not a big fan of coated blades, but dang if they don't look nice with a really polished edge before you use 'em!

Of course, bear in mind that the KaBar isn't meant for shaving your face. It's meant for serving as a multi-use tool on a battlefield, from probing for mines to shanking the Nazi that you ran out of ammo to nail with your Thompson.

 

[cziv]

My default reaction would be to take 'er to the belt and convex that sucker. Which is precisely what I did to mine, actually. I'm not a big fan of coated blades, but dang if they don't look nice with a really polished edge before you use 'em!

Of course, bear in mind that the KaBar isn't meant for shaving your face. It's meant for serving as a multi-use tool on a battlefield, from probing for mines to shanking the Nazi that you ran out of ammo to nail with your Thompson.

I agree 100% - now if I can only find a damn Nzai to shank!

 

[Komitadjie]

Our range is all outa SS guys too! This bum economy is really gettin' to everyone.

 

[Ben Dover]

I agree 100% - now if I can only find a damn Nzai to shank!

Would you settle for one of my graduate assistasnts?

 

[me2]

The steel in my brother's Camillus USMC knife was/is quite soft. It was easily cut with a file. In a case like this, I'd use a very polished edge at 20 to 25 degrees for rough work. If it's mirror polished, it really should slice paper cleanly, regardless of the primary or edge bevel angle. I would say there is some flat spots on the edge for some reason, and you've polished the bevels without really getting to the edge.

 

[bm11]

I sharpened up a KaBar for a friend a month or so back, and I will agree that the steel is very soft. I am so used to working with harder steels that it was shocking how fast I was able to get a shaving sharp edge on it. On the other hand, I would be surprised if the steel was hard enough to hold up to any level of use if you took it down to a 30 degree inclusive.

 

[cziv]

I sharpened up a KaBar for a friend a month or so back, and I will agree that the steel is very soft. I am so used to working with harder steels that it was shocking how fast I was able to get a shaving sharp edge on it. On the other hand, I would be surprised if the steel was hard enough to hold up to any level of use if you took it down to a 30 degree inclusive.

I have mine as close to 40° inclusive as possible. I think that's a good safe edge for this size of blade and it's all around duty. It sure came with a lot wider inclusive angle than that though.

 

[Ben Dover]

I seriously doubt that even 50 degrees inclusive would be excessive for a military K-Bar.