OK...im frustrated

A

Artilary6

Joined
Oct 2, 2007
Messages
132
Been using the Sharpmaker without good results. I had to reshape a bevel, so I used 120 grit sand paper on the triangle rods to do this, and it worked well. The bevel matches the 40deg angle well. I have been sharpening and honing this edge for HOURS and no matter how careful I am and no matter how hard or lightly I try pressing, the edge remains dull as a brick and appears gritty and rough. The bevel itself apears shiny and pretty smooth and clean looking, but the edge mains really rough and reflects lots of light and won't cut paper without ripping it. I can't get this thing sharp and im about to throw it through the window. Please help!
 
It sounds like you might not be hitting the very edge of the bevel when you sharpen your knife. You could try the sharpie trick, where you cover one side in sharpie marker ink, then sharpen and see which areas you're grinding off. Other than that, I would suggest checking for the burr to make sure you're getting it cleanly removed.
 
1. What knife and what steel?

2. Now that you used coarse sandpaper to reprofile the edge, which rods are you using that aren't working?

3. Did you check for a wire edge?
 
KA-bar USMC in 1095. I am using the medium rods and when they didnt work i tried the fine rods to see if it would remove any burr that might be there. I am not certain what a wire edge is or how to check for it. I tried a different knife with the sharpie trick, and realized that that knife would also have to be totally rebeveled because the edge angle was way different that the 40deg on the sharpmaker. I didn't do the sharpie trick with the KA-bar, which i'l go ahead and try just in case im missing the end of the ege.
 
Sounds like you pulled up a burr and have trouble getting rid of it. The gritty sensation is usually tale telling. If I understand correctly you reprofiled to 40 deg and use the Sharpmaker at 40 deg. This way you can not always get rid of the burr. Knock the burr off at a steeper angle and try again. However, by far the best method is to reprofile to something significantly BELOW 40 deg and use the Sharpmaker at 40 deg. Using the Sharpmaker at 40 deg on a 40 deg bevel is very inefficient. You are doing most of the work on the bevel and not on the edge and if you "fall back" (tilting the blade towards the rods) just by a fraction of a degree you are not working at the edge at all.
 
I agree with HoB -- you're wasting your time trying to "match" 40 degrees. You're much much better off going well under 40. 30 is good, even thinner is better. BTW, the Sharpmaker actually has a 12.5 degree per side setting that a lot of people forget (it's on one end of the stand). Use it!

If you're trying to match 40 by attaching sandpaper to the rods, the sandpaper may be riding up ever so slightly as the blade passes over it -- kind of a wave effect. That will give you a slightly convex edge that's more than 40 degrees at the very edge. I know because I've tried it myself and have observed this happening. To determine whether this is happening, get a black Sharpie, and mark along the edge on both sides of the blade. Then, try 10 or so strokes per side on the medium rods at the 40 degree setting -- if the black is not gone at the very edge, it means the rod isn't hitting the edge. Again, go thinner.

Also, jumping straight from 120 grit to the medium rods (about 600 grit) is too abrupt a change. You need 220 and 320 in between.

As HoB indicates, it could also be a burr problem. 120 can leave a pretty big burr.
 
I'll mirror (from experience) what Keith says. Work your way up another grit or two before going to the standard rods. I believe that the Sharpmaker mediums are about 600 grit...don;t hold me to that... so maybe try your 120, then 220 or 280, then 320 or 400 before going to rods.

Like Hob said, I would regrind at 30 degrees, run through the Sharpmaker stones at 30, then finish off with a micro-bevel at 40. 1095 is not a very "hard" steel, and you should be able to get it super-razor-sharp. Don;t give up Artilary....you'll get it. ....and, during frustrating moments, don;t fall prey to the temptation to bear down hard when grinding....just use nice, light to medium pressure. Good luck
 
Artilary6 said:
I am using the medium rods and when they didnt work i tried the fine rods to see if it would remove any burr that might be there. I am not certain what a wire edge is or how to check for it.

I tried a different knife with the sharpie trick, and realized that that knife would also have to be totally rebeveled because the edge angle was way different that the 40deg on the sharpmaker.
Click to expand...

Two big problems here. First you need to understand what a wire edge is and second you misunderstand rebeveling.

There is no need to rebevel to put a secondary bevel on a blade. You only rebevel to make the edge sharper (thinner) or stronger (thicker) for regular use. You definitely do not want to rebevel to match a sharpening system's settings.

If you have a thin grind and you put a thicker/more obtuse secondary bevel on it, that secondary bevel is there to protect the thin grond from deforming under stress. By reprofiling the whole grind the same as the secondary bevel, you are creating a Scandinavian grind. You don't need this.

Now for the wire edge. When you sharpen, you want to make both sides of the blades meet evenly at the same angle. At the extreme edge, this means you are down to molecular levels of thinness. This is a very weak amount of metal, and will bend from side to side as you use the knife.

This is the wire edge, or burr. You need to break it off to leave a very thin, but more robust, edge. To do this on a Sharpmaker, run the blade down the rods but at a higher angle than you used to sharpen it, that is, pull the back of the blade slightly farther from the rod on the downstroke.

Even more helpful, strop the blade. I do this all along on a pants leg or a leather belt. (Stropping is pulling the blade over the surface, back first, rather than sharpening, which is edge first.) If I have an obdurate burr, I will even strop right up the Spyderco rods themselves first.
 
What I like to do on the Lansky system is to use very light pressure from the next finest hone to "strop" the burr on both sides before using it in the normal direction to remove the grind marks from the previous hone. I don't know how well such a procedure would work with the Sharpmaker, but it might be worth a shot.
 
Will 30deg primary bevel significantly weaken the edge and lower hard-use performance characteristics? It seems to me that 30deg is thin and only used for pocket knives and such. I am frustrated that I can't just pass a knife through the sharpmaker and have it become sharp. It seems there is no other way to sharpen it other than re profiling to the 30deg then using the 40 to microbevel. I guess its expecting too much from myself to be able to touch up a factory edge? I would really like to be able to buy a knife and just keep it sharp without grinding tons of metal off of it and grinding away the black coating from the blade near the edge etc.
 
Artilary6 said:
Will 30deg primary bevel significantly weaken the edge and lower hard-use performance characteristics?
Click to expand...
No, even a well shaped/sharpened full-sized axe (limbing, not splitting) will have a terminal angle no greater than 20 deg per side, tapering quickly back in a convex grind. It is absolutely disgusting what kind of edges the customer is offered in some case all in the name of "hard-use".
Artilary6 said:
I would really like to be able to buy a knife and just keep it sharp without grinding tons of metal off of it and grinding away the black coating from the blade near the edge etc.
Click to expand...
Welcome to the club. Hence, this subforum is mainly concerned with sharpening, rebeveling and reprofiling. And yes, often it is worth it to pay for a properly ground knife. There are some companies that have factory edges where you don't have to start reprofiling the moment you buy it (though some would certainly argue that the edges are still too thick), most notably of course Spyderco, since the Spyderco Sharpmaker actually works beautifully on them without any reprofiling. Often, but not always, Companies that put out more expensive knives will put a better edge on their products. It is hard to justify a $100+ knife that doesn't shave (even though even that can be par for the course). It still doesn't mean that they have a good geometry. This is then rather disappointing. The less expensive knives with a good design I would simply approach basically as unsharpened. The sorry excuse for an edge on some of them is no better than no edge at all, but often you can still make a very nice knife out of them when you invest a little bit of your own elbow grease and you got them at a discount, if you will so.
 
There is no reason a Ka-Bar can't be effectively sharpened with a Sharpmaker, without any rebeveling at all. It is a mistake to think the primary bevel has to be reprofiled to the same angle as your preferred secondary bevel.
 
until very recently, I didnt even know that more than one bevel existed. If it is difficult to sharpen a knife with one bevel because its easy to only polish the shoulder if your not careful enough to hold a steady angle, won't the same difficulty be encountered with the micro bevel? And if I were to sharpen an out of the box Ka-BAR with the Sharpmaker, I would have to hold the knife at an angle instead of straight up and down, correct? Being a noob, this would be difficult.
 
If you were to sharpen an out of the box Ka-Bar with the Sharpmaker, you would have to hold the knife straight up and down, and this would not be difficult.

Set up with the Sharpmaker at elbow height, that is, on a kitchen counter with you standing, or sitting with it on a table. Position yourself so the Sharpomaker is in front of the hand you will be using to hold the knife. Hold the knife in a sabre grip, that is, with your thumb outstretched over the back of the blade. You may want to angle the blade very slightly upward at the tip.

Now stroke slowly and gently down the rods, alternately. I now alternate every 3 to 5 strokes, rather than each one, because it allows me to control the angle better, instead of losing my direction with each stroke.
 
As far as the difference in angles from the primary to the secondary bevel, draw yourself a simple sketch of this:

Imagine the primary bevel at 35 degrees inclusive. Now draw in a 40 degree microbevel as the secondary/edge bevel. Now follow this up with a 30 degree back bevel, polishing/reducing the shoulders.

When you put a 40 degree edge (secondary bevel) on a 35 degree v-grind (primary bevel), your v-grind will not come into contact with the Sharpmaker rods, because it is narrower, "inside" them.

When you put a 30 degree back bevel on that 35 degree v-grind, you will contact the v-grind -- at the conjunction of the v-grind with the flats of the blade, smoothing that angle down a bit, reducing the friction with anything cut that the knife enters that deeply.
 
I'm really confused by this thread now. Typically, a knife has a primary grind, and a single edge bevel. This is how you got your Kabar. There are scandi, convex, zero grinds, etc., but you don't have that.

Anywho, with the 30 and 40 degree settings, you could put a 30 degree relief bevel on your knife, then a 40 degree edge/micro bevel. This would transition from your primary grind (I dunno, somewhere around 15 degrees inclusive, I'd guess) to the 30 degree inclusive relief, to the 40 degree microbevel. If the factory edge grind on the Kabar is greater than 40 (grinding the shoulder, not the edge) I would take the time to work it down. I put a ~26 degree relief on a 1/4" 5160 Ranger.

But I personally don't see that as relevant to your immediate problem. At 40 degrees & 120 grit, your knife should be able to slice paper. Something else is wrong. You're at the edge, it's ragged. Maybe check the way the paper is attached.
 
Normally, or rather, usually, the primary grind is about 7 degrees (or, about 15 inclusive as Hardheart was saying). It is the initial angle, ground by the manufacturer, that tapers down from the spine toward the "edge". This primary grind (or bevel) is the black area you see on black coated knives. We users don;t usually mess with it.

The part we play with is the edge....the shiny part on a black coated knife. In fact, it's the primary edge (or maybe secondary bevel). Man...now I'm getting confused!

The primary edge can have a micro-bevel...............or not. Most of my V-grind knives have a micro-bevel, whether I want them to or not. The ones where I attempt a micro-bevel are more pronounced, because there's intent there. The other ones are accidental because I'm tilting the knife, ever so slightly, inward during the final strokes to avoid the shoulder.

You're right, Hardheart, this is confusing....and I'm reaching the conclusion I'm not helping any.

I will agree with Esav though. There really isn;t a need to re-bevel your edge just to match the Sharpmaker. Make the Sharpmaker match your edge. Play around a little with a protractor and some shims under the Sharpmaker's base, trying both the 30 and 40 deg holes. I usually re-bevel my edges, mostly because one side is never the same as the other, and I feel I might as well fix it to my preferred edge angle while I'm getting the sides even. But really it isn;t necessary.
 
Artilary6 said:
KA-bar USMC in 1095. I am using the medium rods and when they didnt work i tried the fine rods to see if it would remove any burr that might be there. I am not certain what a wire edge is or how to check for it. I tried a different knife with the sharpie trick, and realized that that knife would also have to be totally rebeveled because the edge angle was way different that the 40deg on the sharpmaker. I didn't do the sharpie trick with the KA-bar, which i'l go ahead and try just in case im missing the end of the ege.
Click to expand...

KaBar has like 60 degree edge! No wonder you can not sharpen it with Sharpmaker. I had same troubles. You have to rebevel it. I doubt you have any burr on it - you should see and fill burr when it happen - it sounds like you did not.

Thanks, Vassili.
 
Thanks again for everyone's support here. I suspected the KAbar's edge was way thicker than 40deg. Thank you for varifying my suspicion. I have inked the edge and am now gently grinding away on the 30deg slot. The ink is almost gone so I am getting very close to a clean 30deg angle. I am being very careful to maintain good form and alignment during strokes. I also suspect I was applying WAY too much pressure before, trying desperately to rush the precess. I am now applying light to medium pressure and the angle appears to be going well. I have 320 grit sandpaper I will use to smooth the egde out before going to the medium stones. I will then run the edge trough he complete process before creating the micro bevel of 40deg. How will I know when the micro bevel is large enough? I suspect it is simply a judgment call on my part. Thanks again everyone and I will keep you posted on this noob's progress!

PS...What is the benefit of a microbevel over one large bevel?
 
"one large bevel" continues to the very edge getting thinner and thinner which means it is not very durable: it will chip or roll easily. The more obtuse microbevel is very short, does not significantly effect how the blade slips through the material it will cut, but it will also not chip or roll as easily.
 
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