Pull Through Sharpener Angle

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Guy McVer

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Mar 22, 2022
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Before you get on me about not using pull through sharpeners: I know. I don't use them. Don't worry about it. ;)

I am just curious about what the typical angle of a pocket pull through sharpener is. That's all. I've seen a ton of them and the angles are almost never labeled.

So I happen to have a couple of them. One I got as a freebie because I placed an online order over a certain amount of dollars. I forget what it was and from where. I think it might have been SMKW. I would also like to take a moment to thank them for sending me all of those catalogs even though I asked them multiple times to stop sending them, but whatever. It's free paper cut testing material. The other pull through sharpener is one that I bought years ago in a moment of stupidity.

Anyway, I measured the angles myself by eyeballing them with a see-through protractor and a straight edge. Both of them appear to be exactly 40 degrees inclusive. So that got me thinking, "Is that typical? Are they all like that? Or is it just a coincidence that both of these are the same?"

Yeah, I know 2 is a small sample size. That's why I am asking about it.
 
Brands like Lansky or Smith's often - not always - give the preset angle. Smith's seem to use 20°, Lansky 22,5° as a standard angle. Lansky offers several sharpeners that offer multiple angles (17°, 20°, 25° and 30°). Victorinox seem to use 20° with their pen style sharpener. That's all I know.
 
I don't think I've seen a crossed carbide pull-through with anything narrower than 20° per side. And considering what the crossed-carbide types do to an edge, by literally pinching it in scissor-like fashion as it's drawn through, I'd not want to go any narrower than that anyway. A thinner angle is just going to exacerbate the tendency of these sharpeners to more easily RIP the edge as it's pulled through.

Other pull-throughs with rounded rod-type ceramic or diamond inserts won't do the same sort of damage and potentially could do better in a narrower angle configuration.
 
Generally, they're 20° or MORE since their job isn't to actually sharpen your knife at good angles, but rather to impress lay persons at how quick they're able to restore an edge, and that's easiest/fastest to do when your angles are thick.
 
FortyTwoBlades said:
Generally, they're 20° or MORE since their job isn't to actually sharpen your knife at good angles, but rather to impress lay persons at how quick they're able to restore an edge, and that's easiest/fastest to do when your angles are thick.
Click to expand...

Yeah I was thinking along similar lines since the quickest way to reach the apex is to have an angle that's at least as wide or wider than the existing angle on the knife. If your angle is too narrow then it will take forever to get to the apex. Around 20 per side is probably good for that, which explains why the two pull-throughs that I measured looked to be at exactly 40 degrees inclusive.

I don't think it's necessarily to impress people who are ignorant about such things, but instead it is probably more of a practical concern since it does make sense when you break down the logic behind it.

Papilio said:
Victorinox seem to use 20° with their pen style sharpener.
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Which would be weird because the angle on a SAK's main blade is supposedly 22.5 degrees per side. You've reminded me that I have a few of those Vic pen sharpeners. I'll have to get one out and try to measure it.

edit: it's bigger?

The tip of the pen sharpener where the V-notch sits is too small and rounded for me to measure it the same way that I measured the other two pull-through sharpeners, so what I did was to use my big boy brain. I drew two angles on a piece of paper, one at 40 degrees and the other at 45 degrees. I then cut them out with a pair of scissors and matched them up to the v-notch. The 45 degree one looks like it fits, whereas the 40 degree one looks like it might be just a hair too narrow.

It's a bit hard to judge because the notch is so small, but that is what it looks like to me. The 45 degree angle seems to be the correct fit. If you split that in half then you get exactly 22.5 degrees per side.
 
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Guy McVer said:
Which would be weird because the angle on a SAK's main blade is supposedly 22.5 degrees per side. You've reminded me that I have a few of those Vic pen sharpeners. I'll have to get one out and try to measure it.
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A few days ago I sharpened brand new SAK Hiker and the factory angle was 20 degrees per side .... at least that's what permanent marker and angle cube showed.
 
TheOne45 said:
A few days ago I sharpened brand new SAK Hiker and the factory angle was 20 degrees per side .... at least that's what permanent marker and angle cube showed.
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Well maybe it was 20 then. I don't know. I've always heard it was 22.5 from the factory though.

I sharpen all of mine at 20 degrees per side as well just because it's easiest to manage that way. I have a spyderco sharpmaker and some angle cubes and so it's just more manageable to keep it at 20. I haven't had any issues going from a factory edge to a 20 degree per side edge but 2.5 degrees is such a small difference and SAK steel is soft enough that you figure it wouldn't be a significant jump anyway. 🤷‍♂️
 
I can remember that Victorinox has some sharpening instructions on their homepage. They say 20° per side. Opinel knives have a sharpening angle of ~40° (i.e. 20° per side). Although I haven't used the Victorinox pen sharpener for a long time: Both Victorinox and Opinel could be sharpened quite well with this sharpener.
But I don't know if these 2,5° would make a huge difference.
 
Guy McVer said:
Well maybe it was 20 then.
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Well, 2.5 degrees is a small number if you 'measure' it with permanent marker on the edge. Not exactly 3 digit lab precision if you know what I mean. I removed the marker with the stone and measured the angle with angle cube and it showed 20 degrees.

FortyTwoBlades said:
I personally suggest no greater than 15°
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I sharpened my coworkers SAK Hunter a while ago and first I tried 16 degrees but the knife didn't hold the edge. After sharpening I tried whittling my spruce stick but after that it didn't cut paper any more. At 19 degrees it was ok.

https://drive.google.com/file/d/1BcWl3343y0K0fJtZ9VO7F8jrGKsBxOzC/view?usp=drivesdk
 
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TheOne45 said:
Well, 2.5 degrees is a small number if you 'measure' it with permanent marker on the edge. Not exactly 3 digit lab precision if you know what I mean. I removed the marker with the stone and measured the angle with angle cube and it showed 20 degrees.


I sharpened my coworkers SAK Hunter a while ago and first I tried 16 degrees but the knife didn't hold the edge. After sharpening I tried whittling my spruce stick but after that it didn't cut paper any more. At 19 degrees it was ok.

https://drive.google.com/file/d/1BcWl3343y0K0fJtZ9VO7F8jrGKsBxOzC/view?usp=drivesdk
Click to expand...
Honestly a SAK should hold an edge fine at 15° per side. The hardness is sufficient. It makes me wonder if there was a stubborn burr on it that had rolled over during carving.
 
TheOne45 said:
Well, 2.5 degrees is a small number if you 'measure' it with permanent marker on the edge. Not exactly 3 digit lab precision if you know what I mean. I removed the marker with the stone and measured the angle with angle cube and it showed 20 degrees.


I sharpened my coworkers SAK Hunter a while ago and first I tried 16 degrees but the knife didn't hold the edge. After sharpening I tried whittling my spruce stick but after that it didn't cut paper any more. At 19 degrees it was ok.

https://drive.google.com/file/d/1BcWl3343y0K0fJtZ9VO7F8jrGKsBxOzC/view?usp=drivesdk
Click to expand...
That's the best way to figure out what angle works.

I don't go to 15 deg on them stainless steel European kitchen knives either even though some makes have went to that angle.
 
FortyTwoBlades said:
Generally, they're 20° or MORE since their job isn't to actually sharpen your knife at good angles, but rather to impress lay persons at how quick they're able to restore an edge, and that's easiest/fastest to do when your angles are thick.
Click to expand...
Who would you describe as "lay" people?
RF
 
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