Woodcarving Blade Cross Sections....

Eddy Smiles · #1 11-06-2007, 05:09 PM

I was thumbing through an old issue of Chip Chats the other night and ran across an illustration of wood carving blade cross sections in which the author had identified the three most common cross sections found among carvers.....

A ... The general shape of a new knife

B ... The shape found on the knives of most new carvers

C ... The desired shape

Since we have so many new carvers on the forum I thought that it would be a great idea to show a diagram like this. However, I sure didn't want to step on any toes or violate any copyright laws. I know that when I started it took me for ever to figure out why my presharpened knife wouldn't cut and why the experienced carvers kept harping about sharpening and stropping!

Does anyone have a sanitized illustration that they can post?

cats pa · #2 11-16-2007, 12:44 PM

Quote:

Originally Posted by Eddy Smiles

the three most common cross sections found among carvers...

I don't know about you, Eddy, but my cross section has some bulges and saggage that weren't there when I started carving. The desired profile is kinda fading into the past, and I have difficulty sanitizing it sometimes as well...

Parker

Eddy Smiles · #3 11-16-2007, 05:30 PM

Parker.... Someone else on this forum mentioned it the other day but it's how I hone and strop my knives. I lay the balde flat on the surface and then press my finger down on the blade so that the entire blade maintains contact This helps prevent rounding of the blade both laterally and vertically. Then when I've got the blade just about to where I want it (which is technically where you get a wire edge) I life the blade slightly when I stop. This takes off the wire edge and leaves a nice smooth sharp edge. I'm just a novice to sharpening but not having the ready cash to keep sending my knives to SMWC or Little Shaver's I've had to rough it and do my own sharpening. Granted, I've runined a few blades learning but it comes eventually.

cats pa · #4 11-16-2007, 08:38 PM

Oh, wait a minute. You're talking about the blade cross section? I thought you were referring to my cross section...

Parker

Eddy Smiles · #5 11-17-2007, 05:09 PM

Ahhhhhhhhhhhhh!!!!! The light shines! Sorry Parker, somethimes I'm a little slow on the uptake!

Anthony Filetti · #6 11-28-2007, 07:07 AM

Eddy,
I happened to run accross this in my notes, here is a diagram of the cross-section of a tuned knife as per Marv Kaisersatt preference(and mine)...hope this helps..

xsailer · #7 11-28-2007, 08:47 AM

Darn good question Eddy. I am so glad you asked it.

Often I see examples of knife cross sections and they don't look like the ones I order right from the dealers. Not many are an exact wedge, even those that say they are. Maybe folks like us are engineering this cutting edge concept to death but it is frustrating to want to do it correctly and see different shapes and not know if we are maintaining them correctly!
I've spent a lot of time looking at different knife dealers blades and knife makers blades including Ricks resharpened blades. Many are slightly different within 1/8 of an inch of the cutting edge. Since I use several different knives while carving I find myself having to look at each blace before I do anything with it. I've found if the blade is a perfect wedge(yes I'm aware of the correct angle it should be) it is more likely to break away the cutting edge. On Denny and Helvie knives the blade looks to be slightly curved(I don't mean concave)starting at the cutting edge working toward the blade wedge shape. I'm assuming that's when I should apply the often suggested "raise the back of the blade a dimes thickness" when stropping.This curved length is within, say, 10% of the total blade width on each side. Rick's and RW knives appear to be more of a "true" wedge but still have a slight "bevel" right at the cutting edge. When I see these type of sharpen blades I press my finger on the blade side when stropping.

I also would like to view different cross sections of different knives and read the specfic method of the makers sharpening and stropping method.
Please consider my comments as my observations only. I'm only trying to learn as Eddy is and am offering my limited experience. Again most cross sections shown on articles I've read do not look "exactly" like the knife I directly received from the dealer or knife maker.

Anthony Filetti · #8 11-28-2007, 10:49 AM

Bob,
i think it really comes as a personal preference...in saying that the knives i mostly use are helvie and the earlier ones came with a low bevel, I believe that this has changed for the newer knives where the bevel has been raised. The cross-section I showed above is close to how I tune my knives to even before they are carved. The first thing I do is remove the bevel, or when I purchase a knife, such as an REL knife I recently purchased, I look to see if any have been sharpened to remove the bevel. Removing the bevel deters break aways when carving and actually allows for smoother and easier cuts.

Also in the diagram you notice the top, or spine of the knife, has been rounded. This allows me to curl the blade through a cut resulting in cleaner cuts as well. It should be noted that rounding the spine tends to weaken the blade a little, this results in "flex" which for me I like, but with this "flex" you will have to be careful to keep the blade flat when sharpening or stropping. This weakness can also result in a few broken tips while making vigorous cuts, forcing you to learn to reshape and sharpen your knife. If you can accept the properties of this weakness it really is a nice profile to carve with.

...just my 2 cents...

xsailer · #9 12-02-2007, 09:51 AM

Tony, I understand you comments but just for the sake of total cutting edge definition how would you define, using your cross section example, the cutting edge. I'm talking about the cutting edge its self plus 1/8" torward the "spine". The wedge shape to me is the basic shaped sides of the blade. The bevel, if there is one, is located right at the cutting edge and is in fact the cutting edge. It can be a slight, appox 1/64" or smaller, bevel as on a razor knife or in some cases, as on a Denny knife, a curved spline shape bevel which in length is approx 1/8" on a standard size knife(2" long blade). Just a reminder the reason I'm asking is, when stropping, when do you raise the spline a dimes thickness and when do you not. I would think when you have cutting edge that doesn't touch the strop you must, obviously, raise the spline so it may contact the strop.