how to fix bevels and plunge line ?

[N.N]

[FONT=Georgia, Times New Roman, Times, serif]Something I didn't anticipate when grinding is that the spine of the knife is a continual curve without a flat portion. So when it lays on it's back, it wants to rock. It makes the knife comfortable to hold, but is a booger to grind because it constantly wants to rock and not stay at the same cutting angle for the bevels. Therefore, the plunge lines are "wobbily" as well. When I tried to clean it up, it only got worse at the top near the spine where it jumped the original line. I admit I probably rushed it a bit. I ended up just etching and sharpening it from there just to see if I liked the design. Maybe I'll keep this one for myself or use it as a template.[/FONT]

[FONT=Georgia, Times New Roman, Times, serif]I'm going to do it over. So this time I'm thinking about not putting the curve in the profile at the top of the handle until after I've ground the bevels. This will leave the edge of the steel that will be removed later to provide that flat edge on the spine for the grinding. That or make some sort of flat jig to sandwich the knife in to provide that flat to pull on.

Does anyone have any suggestions on doing this the next time or how to fix this one that I haven't mentioned here?

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[Jim Moenck]

If I understand you correctly, it's the plunge cut in general that you are not satisfied with. If my assumption is correct, I'd advise you to go over to Ed Caffrey's website and watch his video. He does an excellent tutorial on fixing that problem. You'll end up with a more gentile transition there, but IMHO your plunge is too sharp and could cause a problem when you heat treat it.

 

[N.N]

I just watched that video, I might try that on this one just to play around with it. But it did kinda answer my question i think. I was more concerned about the double line up at the top of the bevel/plunge. The knife kept wanting to roll or tip in my hand, changing the horizontal angle at which it meets the belt and it created 2 lines. Ed's method will probably fix that. What Ed is doing in that video is really what I was trying to do to clean it up. But I didn't overlap the belt from the platen so it never smoothed out.

The mark wasn't made very deep so I think I might try to go back and grind it out and use Ed's method to fix up the plunge....then properly go up in grits to fix the grind marks I didn't take the time to worry about after messing things up.

But the original problem is as follows...maybe this is a better explanation. When you do a flat grind, you lay the knife on the spine and pull the blade across the belt to cut the bevels, right? The straightness of the spine keeps the grind straight all the way from the plunge to the tip. So with this one, the spine isn't straight, it's rounded, allowing the knife to roll or tip toward the handle and back toward the tip of the blade. With that happening, how would you go about keeping the angle at which the bevel meets the belt at the same angle, horizontally...does that make sense?

Got some microsoft paint art to give you a better idea of what I'm talking about. how to keep straight a curved spine?

 

[rhinoknives]

When I grind a blade with a curved spine I just follow the curve and bring the handle up in the same arch as the top of the spine. I am grinding a part of a circle so to speak.

Does that make sense?

 

[Lyon]

Scribing lines will help a lot. One down the center for tip alignment and then one more on each side of center for another guide line to help watch how the taper in is progressing.

 

[N.N]

the scotchbrite belt was actually enough to even it up. I still have some cleanup to do, but Ed's video gave me exactly what I needed. Thanks Ed! And thanks Jim for pointing me in that direction. I just didn't take it far enough the first time and started worrying that it wasn't going to work. But it did in the long run!

 

[Jim Moenck]

Glad to be of some help pointing you in the right direction.

 

[N.N]

Better