Spyderco Forums

Teaching a rookie to sharpen Spyderco serrations on Tormek

video https://youtu.be/dgFJPv5M4nw

Hi KnifeGrinders,

Welcome to our forum.

Thanx for the link.

sal

Okay, I hate to be critical though there is not much I like about this sharpening video, though I can learn from good and bad techniques. First off, I'd hate to be this rookie and second, this method really shortens the life of the serrations. I never attack the serrations from the flat side grind and if I hone or deburr it's to the flat side. I own a Tormek and mainly use it for plain edge cutting tools and use the Sharpmaker, a dremel tool, or a detail ceramic file set for serrations.

This is just my 2 cents worth of knowledge and 2 cents is even a high price for that.

Thanks for posting and I hope this stirs input. Dan

Qcrazy wrote: ↑

Sun Jan 31, 2021 10:20 am

...this method really shortens the life of the serrations. I never attack the serrations from the flat side grind and if I hone or deburr it's to the flat side.

Have to agree with Q.

Looks more like how to ruin a perfectly good knife. Sorry. Buy a sharpmaker.

Well, all professional sharpeners sharpen serrated knives from the flat side.

My approach to sharpening serrations is better explained in my post The Saga of Serrations on the Australian forum:
https://www.australianbladeforums.info/ ... ers/46726-

knifeGrinders wrote: ↑

Sun Jan 31, 2021 12:51 pm

Well, all professional sharpeners sharpen serrated knives from the flat side.

I understand. To earn a living, a professional needs to work quickly and move on to the next job. Welcome to the forum, BTW!

Bolster wrote: ↑

Sun Jan 31, 2021 1:21 pm

knifeGrinders wrote: ↑

Sun Jan 31, 2021 12:51 pm

Well, all professional sharpeners sharpen serrated knives from the flat side.

I understand. To earn a living, a professional needs to work quickly and move on to the next job. Welcome to the forum, BTW!

I guess it would depend on how badly dulled the serrations were, but it seems that you could likely have the knife sharpened using a Sharpmaker in much less time, while also preserving the life of the blade.

I spit out my tea


But more seriously, what's the backside supposed to look like when it's done? Neither knife is shown in the video.

Perhaps it's because it's a beginner sharpening it..?

I've stropped the backside on serrated knives before, but I tried to make sure it was the entire grind, not just at the edge.

Next week; teaching the rookie how to swim by chucking them in the deep end of the lake.

Week 3; teaching the replacement rookie how to run with scissors.

I think I'd someday try a paper wheel but not an actual stone like this. Too much metal removal when it could easily be done on a Sharpmaker for practically no metal removal.

knifeGrinders wrote: ↑

Sun Jan 31, 2021 12:51 pm

Well, all professional sharpeners sharpen serrated knives from the flat side.

My approach to sharpening serrations is better explained in my post The Saga of Serrations on the Australian forum:
https://www.australianbladeforums.info/ ... ers/46726-

I don't. I use a sharpmaker to sharpen serrated knives, and give different quotes than I do on PE.

spoonrobot wrote: ↑

Sun Jan 31, 2021 2:17 pm

I spit out my tea


But more seriously, what's the backside supposed to look like when it's done? Neither knife is shown in the video.

Oh no. Oh no no no....

We need to differentiate between sharpening a serrated blade, and restoration of the worn serrations.

Grinding in the serrations is not sharpening, it is restoration. We restore serrations with diamond coated rods of matching diameter.

To simply sharpen a serrated knife, we grind the flat side of the blade on a very fine stone, and inside the serrations we only deburr.
It goes without saying that we polish the grind on the flat side on a paper wheel with chromium oxide. This part was omitted in the video.

I clicked on the link provided to the Australian knife forum post. Here's KnifeGrinder's relevant opinion regarding the Sharpmaker:

"The Spyderco Tri-Angle Sharpmaker rounds the peaks.
You might have seen videos where people use sisal wheel on a grinder to sharpen serrated knives.
The drawback of this method is that it rounds the peaks… and if you round the points up, you defeat the purpose of sharpening, because the rounded peaks will not rip."

If you mean what I think you mean, then it seems like you attribute the cutting ability of a serrated knife to the shape (in this case, pointiness) of the peaks. It sounds like you think pointier serration peaks cut better than "rounded" peaks. However, a lot of users on here posit that the the shape of the peaks is different than the sharpness of the edge at the peaks, and that in fact round (yet sharp) peaks cut better than pointy peaks, because there is less chance of snagging and dragging with rounded peaks. And it is clear that the Sharpmaker can make the peaks sharp, regardless of the shape.

Hi KnifeGrinders,

Interesting discussion.

A bit of history might open the discussion some?

I studied serrations quite a bit, especially under the microscope from 1975 on. We introduced our Triangle Sharpmaker in 1978 which I invented to be able to include sharpening of serrations. I have been studying serrations ever since. I'm all about the cut. We make what we call "High performance matter separators".

We introduced our first serrated kitchen knife in 1982 and our first serrated pocket knife in 1982. We had to solve the sharpening problem before we could offer teeth. We felt that most people buying our serrated knives would also buy our Sharpmaker, That proved to be wrong.

For the first 10 years, the "Professionals" would tell customers with serrated knives that they couldn't be sharpened. "Here, let me grind those serrations off and give you a real edge". We received hundreds of knives back from customers asking us to try to re-serrate their knives and felt they had been "ruined" by "Professionals".

I worked with many makers to try to get the serrations made at the factory in what I thought was the best shape and angle. This was and still is a daunting task, because they all considered themselves to be "Professionals" and they kept trying to tell me: We have been making knives for 3 generations, who do you think you are to tell us how to make knives"? We re still working on the best way to share this information so the knives can come from the factory a little better.

I recognize that different edges work better for different things, but I learned that in the world of teeth, there is little real useful overall understanding. We're all learning since the folding pocket knife with teeth is a relatively new offering (1982). That's one of the values of this forum. We feed each other knowledge and experience.

I've been bucking this for most of my "professional" career. Many have always thought that the teeth need to be long and sharp. I guess they think that penetrates better or "looks" better. I have learned that the function of the teeth was to provide penetration, such as starting a tomato, and to protect the "real" cutting edge which was protected by the teeth from hitting hard stuff. In fact our K04 and K05 serrated kitchen knives have one of the 3 teeth in a set that is longer to protect the other 2 teeth.

While there are many opinions on serrations and mine is just one of those, I believe the teeth need to be rounded a bit so they don't snag. I feel this way about points in general, but that's a topic for another discussion. :cool:

In my humble opinion, I think that to preserve the long pointy tooth would be good for re-serrating blades that have worn down too much and need regrind?

Just my thoughts to share.

sal

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"Improvement is our evolutionary obligation to humankind".

^ yep


I'm going on 4 years of carrying nothing but serrations. Rounder teeth are without a doubt less snaggy and still cut very aggressively. The teeth (whether sharp or rounded) focus the pressure of a cut into a much smaller surface area than a plain edge, and so even rounded teeth will penetrate and initiate a cut.

In our sharpening we take utmost care to preserve the original geometry of the Spyderco serrations, the peaks and the valleys.
From this thread I've learnt something new about rounded teeth, and this is good.