Carving Knives

[bud812]

I obtained a set of carving knives but are in bad shape. My question is are all carving knives sharpened at the same angle?
Like is a Chip carving knife sharpened at the same angle as say a detail or roughing or even a whittling knife? I guess what I'm asking is what is a good angle to sharpen my knives? Thank You Bud

[Kenny_S]

I am not a chip carver but I would thing the chip knives would be a different angle as detialing or roughout knives. However, I believe the latter two can have different angles and still be roughout or detailing knives. I usually has a 17 degree angle on my knives but that is just me. Seems to work for m. I can't say what other carvers have on their knives. Helvie knives have a broader angle than most knives but if you know how to strop them, no problem. I use them for harder woods like walnut.
Hope this has helped.

Bud,
The angle is determined by the tool maker; (normally) if you sharpen at the same angle it will be correct for that tool.

To tell you the truth, I have never measured an actual angle on a knife; carving chisels yes.

Chipcarving knives are ground to a 10 to 15 degree angle I believe.

The detail knives I make are about the same angle as a chipcarving knife.

Roughout knives require more mass behind the cutting edge and therefore require a larger angle. Most knifemakers have their own idea of what angle and type of grind works best.

Myself, I believe that a flat to slightly convex grind works best on my knives.

Other knifemakers believe a visible convex grind provides better edge support.

There are even those who grind a flat surface on one side of the blade, with an angle and micro-bevel on the opposite side. On the surface, this sounds kind of silly, but if you look at the dynamics of chip formation, it does make sense.

My problem with that grind is I turn my knife over a lot while carving and that would eliminate any advantage it might provide.

Since I also 'roll' my knife through the cut, I like a very slight convex grind; not so much that you would notice it with the unaided eye.

A concave grind will not turn at all and is unusable for whittling knives; even though it would simplify sharpening.

You may think I have gotten off the subject of sharpening, but you sharpen at the angle a tool is ground to.
Now if the angle is incorrect, then it must be reground for the intended use.

That is the answer; the intended use determines the angle; and you sharpen at that angle.

I re-read your question and my answer :-/

Let me give it another shot.

You said the knives are in bad shape; if you were to look at the blades in cross-section, you would probably see a convex shape from the center of the blade to the cutting edge.

What you need to do is flatten that back out; not just put a sharp edge on the knife.

What you are shooting for is a flat angle from the back of the blade to the cutting edge. If you are sharpening by hand, it will take some time.

If you want a textbook answer, 15 to 30 degrees for most knives.

Good luck

[bud812]

Thanks Guys.....now that I have a starting point I'm headed in the right direction. You've really been a great help. Thanks again

Rick: If you have a knife that has too much of a convex shape, (it feels thick,) will it weaken it too much if you take most of the thickness out and make it a flat grind? (It would be used on Bass wood and maybe a little butternut.)

Thanks Ken in So Cal

Ken, it probably will not weaken the blade if you don't thin the blade too much.

What brand of knife are we talking about?

[dart]

Hi Rick, I have a Hirsh carving knife with the traditional shaped blade. I haven't measured the angle but it has a flat ground blade. It was a good knife when I first got it but now I think it is too thick at the top of the blade and the flat of the blade seems to hit the wood before the edge does? This seems to keep the knife from cutting the way it should. I hope I am making this clear? I am wondering if I should grind the blade thinner , try to put a very slight concave or convex in the blade, or what to do to get the blade back into cutting action. This is really microscopic and sounds like a silly question, but I read your statements and I agree with what you say. I have a grinder and know not to heat the metal up or it will lose its temper and that's no good either. But I have quit using the knife due to it not cutting the way it should. It is sharp as a razor but I can't get the sharp edge to go to the wood as the blade interfers with it. Hmm..?? What do you think?

[AlArchie]

Sounds like you have too steep an angle on the blade. Might work for an axe, but not a knife.

In all probability you don't have to go the 'grinder' route, but that will speed things up a bit. A good coarse stone or medium diamond stone and some careful hand work, should bring your blade back to like new performance in about 20 minutes or less. Place the blade flat on the stone, then lift the back about the thickness of a new dime, and sharpen at that angle. 20 strokes on either side for about 4 or 5 cycles, then start decreasing the strokes on each side by one, till you are down to one stroke on each side. that SHOULD put your blade back where it belongs. Strop it lightly to take off the wire edge and you are back in business.

Al

Dart,
Sorry I couldn't respond sooner, I was gone to carving shows the last couple weeks.
Hirsh knives, (although I have never used one) I have heard many good comments on that brand of knife. I understand they are no longer being made. (let me know if that is incorrect).

I know exactly what you are talking about; you need to remove the 'hump' between the cutting edge and the heel of the blade. Try to maintain the original angle; it will take some time to do it right.
Good luck, Rick