Spyderco byte August 2024 -Edge-U-Cation®A Deeper Look at Spyderco Serrations from the Man Himself
One of Sal Glesser’s—and Spyderco’s—most revolutionary achievements in the knife industry was the addition of serrated edges to modern pocketknife design. Although true saw blades were included in folding “escape” knives as early as World War II and serrated kitchen knives have long been commonplace, it wasn’t until 1982 and the C01 Worker™ model that real cutting serrations were featured on a pocketknife blade. Shortly thereafter, the C02 Mariner model added them to a sheepfoot-bladed folder, pioneering the concept of the modern rescue knife.
Many knife users are hesitant about investing in serrated blades because they believe they are too difficult to sharpen. Often, they have never enjoyed cutting with a properly designed serrated edge and don’t understand its performance advantages. While there is no substitute for that hands-on experience, the more you know about serrated edges, the more you can appreciate them.
To start that process, here’s some fascinating history that Sal himself shared on Spyderco’s Internet forum from his early days as a “pitchman.”
We knew that there were some advantages to serrations, so we really studied "teeth" when developing our sharpener. The multiple sized serration we traced back to Germany in the '40's. Another "Pitchman" named Ronny Popeil (Ronco - a great inventor, pitchman and producer) developed a kitchen knife based on that concept called the "Feather Touch" knife. It was a really effective kitchen cutting tool, though inexpensively made. Most of the knife Pitchmen bought and sold his knife. It had one large serration and one small serration.
Then another Pitchman named John Spyker (another really good Pitchman) designed a larger knife with one large serration and two small serrations called the "Sharpcut Carving and Serving knife". Made in Ohio, John had "broken the Ex" (exclusive) of Popeil's knife, sold them for less money and the Pitchmen eventually gravitated to the new "Pitch Knife."
Then another company designed and created a similar and larger model promoted on television called the "Ginsu" knife. All these designs were based on the multiple sized serrated edge. Gail and I with microscopes studied serrations to determine why they worked better and how to sharpen them. This was in the late 70's. Once we felt we had it nailed down, we produced the "201 Sharpmaker.” We then produced our own kitchen knife, which we still make today. It is our serrated "Utility" knife and general kitchen performance is exceptional. In 1981, we produced the first "Clipit®" folding pocket knife and in 1982, we produced the "Mariner" serrated pocket knife. Early models were thicker at the edge and it took us a while to get our maker to make the edge thinner and thinner.
Sal’s comment on the thickness of the edge is actually very significant, as it touches on one of the secrets of the effectiveness of serrated edges. Knife enthusiasts know that thinner, more acute edges cut better—provided both the metallurgy and the heat treatment of the steel support that geometry. While most blade grinds create a “V-shaped” cross section at the edge, serrated edges are only ground on one side, creating a “chisel” profile that is literally half the cross section of a “V.” Logically, the “included” angle of that chisel-ground edge is half that of a comparable V-ground edge. On a PlainEdge™ blade, that would leave the terminal portion of the edge extremely fragile and prone to rolling or chipping. However, the unique structure of serration teeth and, very importantly, the ridges between them, actually reinforces the structural strength of the edge. Despite its thinner edge geometry, it remains strong.
Serrated edges are chisel ground, so they have half the included angle of V-ground edges.
With regard to the sharpening of serrations, Sal specifically designed the Tri-Angle Sharpmaker® to sharpen PlainEdge, partially serrated CombinationEdge™, and fully serrated SpyderEdge™ blades with equal ease. In the process, he also created one of the very few sharpeners on the market that also puts an edge on hawkbills, recurves, tantos, Reverse “S” blades, and virtually any other edge profile with no significant change to your technique. By doing the same basic thing, you get an amazingly sharp edge, no matter what the blade shape.
To sharpen a serrated edge on the Sharpmaker, the secret is to use a slightly looser grip and to go slowly. This allows the edge to remain in contact with the rounded corners of the stones along its entire length, flowing in and out of every serration scallop instead of “chattering” across the ridges of the teeth. To maintain the integrity of the beveled side of the serration, it works best to use a ratio of three strokes on the bevel side to a single stroke on the unbeveled side, which removes the burr at the edge.
Is a New-in-the-Box Serrated Edge Sharpest?
While many people believe that a SpyderEdge cuts best when it is fresh out of the box, according to Sal, that’s not really the case. This quote from the Spyderco Forum provides some excellent insight into the manufacture of serrated blades and why sharpening on the Sharpmaker actually makes them cut better:
Serrations are made by grinding the edge of the blade with a formed wheel. The wheel is formed in the shape of the serrations. Each time a blade is serrated, there is a little wear on the wheel. After 40-50 blades, the wheel must be re-formed as its shape changes, so no two serrations are exactly the same. Each maker has their own ideas of how to make the serrations even though we show them what we would like. By making the serrations more pointed, the wheel can be re-formed less often. However, in my opinion, if the serrations are "too pointy,” they tend to snag. When I get a new serrated knife, I sharpen the serrations on the Sharpmaker. I use 30 degrees and 3/1 ratio with the non-ground side almost flat to the stone.
In my opinion, the best serrations are the result of proper sharpening on the Sharpmaker using the methods that I show on the Sharpmaker video. Using the Sharpmaker as I instruct, the tips become slightly rounded, the inside of the serrations are sharp, micro-beveled, and the cutting performance is more effective. I should mention that others have other opinions on the way serrations should be and how to sharpen them.
Serrations in the Kitchen
At first glance, the SpyderEdge grind of our K04 and K05 Utility Knives may seem identical to all our other SpyderEdge blades. If you look a bit closer, however, you’ll see that it’s not. Once again, Sal explains it best:
The center tooth on the K04 and K05 is slightly longer, which lifts the other two teeth off of the cutting board. It's the board that dulls knives, not the food. The teeth protect the cutting edge. The center tooth protects the other teeth.
You may also wonder why Spyderco’s K01 Bread Knife does not share the SpyderEdge pattern, but instead has a uniform serration pattern. Sal explains it this way:
We use a single size serration on our bread knife because testing in Japan by our kitchen knife maker indicated that on hot, fresh bread, it worked better.
In another post, he elaborates:
I would suggest trying out a Spyderco Bread Knife. Also sharpen it a few strokes on the Sharpmaker. I can offer some theory:
1) Very thin blades make a big difference. It took many years for me to make the makers in Seki do them the way I wanted. They felt they knew better than me how to make knives, since they were 2nd generation. Eventually the popularity of the brand and serrated edges convinced them to let me lead. I always appreciate their opinion. But now at least we discuss it.
2) I can only tell you that people that make hot bread say it's better. That's why I suggest you try it. It's quite thin and an excellent kitchen steel. Gail is an excellent cook (I mean really good) and she kind of drove the bread knife design.
3) Serrations take a little more thought:
A) On a plain edge knife, the center of effort (cutting effort) goes in only one direction. Down at 90 degrees to the cutting table. It might vary due to the moving motion of the blade?
B) On a serrated edge, the center of effort constantly changes in an arc, cutting the material from many different directions very quickly. The center of effort to the material is 90% to the top of the shape of the serration, which is an arc.
C) The edge geometry, angles and arcs all make a difference. "When one of our serrated edges is proper and finely tuned, it will impress.”
If you’ve never used a serrated edge or mistakenly believe it can’t be sharpened, take it from Sal himself and give it a try. Once you realize its advantages and see for yourself how easy it is to sharpen, your perspective on knives will never be the same.
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