Sharpening spearpoint blades

A

AlphalphaPB

Joined
Apr 29, 2002
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1,273
Most of my knives have spearpoint blades, and I have trouble sharpening the very tip on the blades that aren't completely flat, that is, the ones where the tip is reinforced somewhat by a thickening "spine" down the center of the blade.

I use a Sharpmaker, and the magic marker method tells me that even though I'm keeping the contact area of the blade perpendicular to the stones, the angle isn't steep enough at the tip. Is this because of my poor technique, or is it because the angle at the tip really is at a higher angle?

Thanks for any help anyone can give me.
 
Hi Alpha. I have a couple of spearpoints and when I sharpen them on the Sharpmaker I run them on the edge like you would a recurve blade. This will get the tip and then I switch to the flats for a few final passes and don't really worry too much with the tip if I'm not able to keep the edge on the stone as it has already been sharpened via thew edge. Hope this helps.
 
I have same problem with any tip i think, with Sharpmaker- it is hard to explain but I blieve the sharpening angle slightly changes as the stones "climb up" the belly of the blade, therefore I simply sharpen the last ~1/4 inch of the tips on my blades on the ceramic rods in "flat position" by hand.
Good luck, let us know if you figure out a good way!
Martin
 
I think it's harder to eyeball the angle of the blade at the tip, and the angle on the Sharpmaker should be *slightly* more shallow at the lower part of the rod (since at the upper part, with the greater lever forces, the rods will move slightly more outward than at the bottom). This reason for difficulty would be more tied to crock-stick type sharpening systems.

The average number of passes for each area of the blade decreases at it reaches the tip (at least for me), because I have to go slow and careful. The up-down angle of the blade is also much less consistent there, since each time I have to estimate the amount I should "angle-up" the handle. So maybe I just haven't changed the angle at the tip much, compared to the areas of the blade closer to the tang. These reasons would be due more to the nature of the blade and its effect on sharpening (i.e. average number of passes over each area of blade).
 
Frequently, the knives I have seen have greater angles near the sweep of the tip. You can either just let this thin out as you sharpen, or do it all at once just working the tip down. The Sharpmaker is slow for that though, I would use an x-coarse benchstone and freehand it. You are only shaping so there is no need for precision. Once you have the angle lowered, sharpen as normal on the Sharpmaker.

-Cliff
 
Ah, I was hoping that it's a geometry thing, since it proves I'm not that horrible at sharpening. :)

Thing is, I've tried lowering the angle freehand on a bench stone, and the end result was that the grind lines started looking terrible. The blade just wasn't designed to have the lower angle up at the tip, and lowering the angle up there will mess up all the pretty lines. My M16-13Z looks like utter, utter crap. Even non-knife-nuts think so, so I think it's really pretty bad. :)

I think what I'll do is angle the blade outward a bit when I get to the tip. Not terribly accurate, but the best I can do.
 
Yes, it will make it look very crappy. Something else to consider is free hand stropping on sandpaper on a soft backing. This will induce a light convex nature to the bevel, but the backing will give to conform to the edge angle and so it will naturally fit the tip and the main edge body at the same time.

-Cliff
 
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