Thoughts On Pull Through Sharpeners?

Advertise with us
Shop Knives and stones on ebay
Japanese Knives - by Tokushu Knife
Kitchen Knife Forums

Help Support Kitchen Knife Forums:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
W

Witterings

Active Member
Joined
Jan 23, 2024
Messages
30
Reaction score
5
Location
Chichester
Intersted to hear people's thoughts on pull through sharpeners similar to his one?

https://www.amazon.co.uk/Diamond-Ed...x=knife+sharpener+diamonf,aps,105&sr=8-5&th=1

I had something similar when I was a kid and used to have camping knives and must admit it kept the razor sharp but the one I had you could certainly see how it ate into the blade slowly reducing it.

There's certainly a trade off of it works really well and incredibly quickly, they're so simple to use and takes seconds to get a really decent edge and it'd still take an awful lot of use before a knife needed replacing.

If you were in a commercial situation (I'm not) and wanted to conert that into time is money, you could spend a lot of time with a whetstone but it may be more economical to buy a new knife once every few years instead and the reality is all sharpeners work by removing metal .... some maybe just a bit more than others?

Personally I would never have considered one but was chatting to a Chef today who's run some very well known / major establishments and that's what he uses and some fairly high end knife manufacturers like Robert Welch include them with their knife sets / blocks.

Interested to hear what other people's thoughts are, at the end of the day if it does the job incredibly well and quickly but maybe removes a smidge more metal than other methods so the knife lasts 6 instead of 7 years does it really matter?

Unless there's some other reason for not using them I'm not aware of?
 
They suck.

Just because someone is a chef, doesn't mean they know what is best for knives, especially hard steel knives.

Just think about the mechanics at play. When we sharpen, what are we trying to achieve? A fine apex that is well de-burred. By and large, we do this by grinding on the metal until it rolls over and forms a burr. When satisfied, we then spend time carefully de-burring that apex to hopefully leave behind a fine, sturdy edge.

How can a pull-through sharpener do either of those things? They literally rip metal parallel to the edge. What may present itself as "sharp" is a fleeting edge often with excess material removal.
 
I don't think this is the right forum for that, but basically they give you a mediocre edge that doesn't last very long. Granted that may be satisfactory in some commercial settings.

It eventually will ruin a knife but I would say you might get 3 years instead of maybe 15 or 20 using stones.
 
As to knife longevity, again, you need to think about the mechanics at play. It is less about the life of the knife and more about the cutting geometry. As you remove metal from the edge, you're going higher up into the grind and that means thicker. That's why so many of us thin at some interval.

Those pull-throughs will get you to that point much faster and leave you no way of thinning once you're there.
 
Brilliant and thank you to all for your replies ... must admit it was my initial thoughts, I guess he's in a different world of just need it to work .... and need it to work NOW ... more replacement knives is probably a small cost vs time in a highly pressurised environment.
 
HumbleHomeCook said:
As to knife longevity, again, you need to think about the mechanics at play. It is less about the life of the knife and more about the cutting geometry. As you remove metal from the edge, you're going higher up into the grind and that means thicker. That's why so many of us thin at some interval.

Those pull-throughs will get you to that point much faster and leave you no way of thinning once you're there.
Click to expand...

How do you "thin" / what does it mean, I'm guessing it's something to do with getting to the Apex (if that's the right word? ) / shoulder of the blade??
 
Witterings said:
How do you "thin" / what does it mean, I'm guessing it's something to do with getting to the Apex (if that's the right word? ) / shoulder of the blade??
Click to expand...

Thinning is about thinning the primary grind of the blade to maintain the geometry as sharpening moves the edge bevel up the knife.

 
On soft Western stainless, they remove a lot of metal, which leaves the knife thick behind the edge. Even worse, they leave behind a fairly sharp but incredibly fragile wire edge which will seem to cut well until the first board contact.

On hard Japanese style knives, they will chip the edge. On very hard, very thin BTE knives, the chips may be many mm deep.

Both styles of knife will respond much better to stone sharpening.

Note that stone sharpening is as much (maybe even more?) about removing the burr as it is about forming an apex.
 
It happens to me every week that a customer comes to see me to have their knives sharpened while at the same time they bring their pull through. The question is always the same: is it good for sharpening my knives? The answer I give is: if it were that effective, we wouldn't be here talking about it! (obviously with a touch of humor!)

I understand that not everyone has the desire to learn and spend hours trying to master sharpening and I understand that 100%. I preferred to take a little time to explain how to properly maintain the cutting edge, explain what happens when seen up close, why a knife is sharp. In short, make them understand that it is more complex than just pulling a knife through this device. Most of the time they are really surprised and interested on the subject.

Sometimes I have customers who write to me after I go to sharpen their knives and tell me that they threw away their device. A small victory 🙃
 
Witterings said:
Brilliant and thank you to all for your replies ... must admit it was my initial thoughts, I guess he's in a different world of just need it to work .... and need it to work NOW ... more replacement knives is probably a small cost vs time in a highly pressurised environment.
Click to expand...
At my work, every few days I'll give the knives a touch up on the stones. Makes it quick when you don't wait to long. In between that time, the cooks use a honing rod. We do use an outside knife rental/sharpening service, they come once a month and switch out the knives.
 
Generally, what are people's thoughts on Diamond Stones vs Whetstones and also teh ceramic rods like the Lansky Turnbox and Spyderco Sharpmaker?

I have used just a whetsetone in the past and got them razor sharp but it took me absolutely hours, I recently made a 20 degree agled board to mount a diamond stone on and use that for the "heavier" work and then finish them with a Turnbox and it seems to work quite well.

I was looking at the pull through as potentially being quicker / easier but as that's so heavily advised against will avoid.
 
Witterings said:
Generally, what are people's thoughts on Diamond Stones vs Whetstones and also teh ceramic rods like the Lansky Turnbox and Spyderco Sharpmaker?

I have used just a whetsetone in the past and got them razor sharp but it took me absolutely hours, I recently made a 20 degree agled board to mount a diamond stone on and use that for the "heavier" work and then finish them with a Turnbox and it seems to work quite well.

I was looking at the pull through as potentially being quicker / easier but as that's so heavily advised against will avoid.
Click to expand...

So, not to be snarky, but all sharpening stones are whet stones. Whet just means to sharpen. I suspect you mean water stones. Common mix up but worth getting right early. :)

Let's tackle fixed style systems first. They aren't bad. I used a KME for some time. Lansky's have too much slop and aren't worth it. The Sharpmaker is just a vertical freehand system. People don't like to hear that but it's true. The only difference is you're having to keep the knife straight up and down vs. holding it at an angle. I say if you're going to go with a fixed system, don't cheap out. Edge Pro, KME and TS Prof are good systems. Wicked Edge is too spendy IMO.

What do fixed systems bring to the party? Consistency, repeatability, and can help you learn fundamentals. That's it. In just about every other way, they are inferior to free hand sharpening on stones. They are not a miracle cure and all of them require learning and understanding. Lots and lots of people buy fixed systems thinking they do all the hard stuff for you and are sorely disappointed when they discover that is not the case. All the same fundamentals apply here as to free hand sharpening. You need to know what stone to pick when, what is an apex, a burr, when to flip, how much pressure, and on and on.

And their cons are real. They are not good for longer blades. When I used a KME, I was pretty focused on EDC/Outdoor knives and cheaper kitchen stuff. The fixed systems cannot adjust for the belly and changing geometry of the longer blades and will eventually flatten them out and create huge bevels. They are slower than free hand. I know that might hard to swallow right now but trust me, they are. The stones are almost always smaller than a bench stone so you're already behind both in surface contact and stroke. Stone swapping takes more time. And unless you want to leave it set up, you have set up time. They can also be messier with everything dripping down above your hand.

The reason it took you so long on bench stones is either your technique, your stones vs. the steel type, or a combination of both. You can learn to do it and there is a ton of information here and on YouTube to help you. And the folks are always here to help as well. Search the forum for things like "new to sharpening" or "first stones' or "beginner sharpening set up", that kind of thing.

Diamonds have their place but they are more niche than ceramic stones.
 
So if you got 100 bucks to drop on a trizor at least spend it on the rolly tumbler thingys.
 
Sorry for the snarky one liner. I have family visiting this weekend so I haven't had much of a chance to respond. I have used pull throughs extensively over the years in a commercial setting.

Pull through sharpeners are very damaging to knives. One step up from using an angle grinder in terms of its crudeness. Not the way to establish good knife geometry. And kitchen knives performance is all about the geometry. The apex is incidental. The pull through often wrecks the geometry and leaves wicked burrs sticking out from where the edge should be pointed in several different directions except toward the food. I did work with one person who ran the garde manger dept at a big ass hotel. She used a motorized pull through on her extensive kit of cheapo restaurant supply knives. She got better results out of that thing than anyone I've encountered. Far superior to what the bench grinder in the van rental knife guys can do. And once I showed her some simple deburring / stropping techniques to do after the machine. I would say the results were pretty acceptable. But acceptable in that context. 5-10$ knives that she uses for a few months or a few years, grinding them once a week or so and replacing them if they get ground down too far. Working 12 hour days chopping chopping chopping for up to 2000 covers a day.

If you are using cheapo restaurant supply knives and your options are can rental knives or using one of the nicer pull through things then I would go with the pull through things.

However, learning to freehand sharpen is far more valuable and versatile. A fine ceramic honing rod works great in a pinch. Otherwise I like diamond whetstones for dealing with cheapo stainless. I am a teacher more than chef nowadays. I maintain a fleet of about 60 Amazon basics knives that get used by everyone from 8-88 years old. Here is my field kit:

First line of defense is a 12" white Mac ceramic honing rod for sharpening the microbevel.

If it needs a little more then I go to the Naniwa Diamond 600.

If there is damage or I need to do thinning then I use a Norton Crystolon combination coarse/fine.

I do not find ceramic whetstones to be ideal for cheapo stainless.

If you have nicer, harder Japanese style blades then I would start to think about ceramic whetstones. But I don't really recommend going that route if you are in a serious commercial situation.
 
Robert Welch is fairly high end? Well I guess it is april 1st...

As for pull-through's... IMO they only really start making sense when they invent a pull-through that also thins behinds the edge... or when the alternative is 'not sharpening at all' as you see in many homes.
 
stringer said:
I have honestly never heard of Robert Welch.
Click to expand...
They're a British brand...basically fancier looking yet bog-standard mass market crap... no mention of where it's made so definitly not in Britain.
Originally they're into tableware so cooking knives are probably just a side hustle for them like you see many brands doing these days.
 
And I guess the biggest advice I can give (that lines up what others have said):
Stop overfocusing on the actual edge / apex, and worry more about the area behind it. This is also the weakness / flaw in most guided systems. They're all about 'perfectly holding angle X'. But for cutting food it's not really all that relevant for cutting performance whether your angle is 15, 18 or 20 degrees as long as it's thin enough behind the edge. You only really start noticing such differences if the knife is too thick in the first place.

You can have a knife that's sharpened to the most perfect 1 atom apex in existance but if it's too fat behind the edge it still won't cut carrots worth a damn. Yet if a knife is proper thin you can even outright blunt it and it'll still do well on many things.

That's also why you almost invariably end up with whetstones, because they're the one tool that really allows you to easily tackle all aspects of performance, both the edge itself and the area right above the edge.

As for diamonds, they mostly excel when you get into fancier super steels with alloys where regular stones start to struggle. So how useful / needed they are depends a lot on the material in your knives.
 
Jovidah said:
Robert Welch is fairly high end? Well I guess it is april 1st...

As for pull-through's... IMO they only really start making sense when they invent a pull-through that also thins behinds the edge... or when the alternative is 'not sharpening at all' as you see in many homes.
Click to expand...

The nicer motorized ones do have a couple different settings that approximate thinning. And like I said, especially with some basic deburring at the end. It might make sense for bog standard stainless if the other option is rental knives or not sharpening at all. Learning to use a honing rod and a sharpening stone is far more valuable and effective.
 
Jovidah said:
As for diamonds, they mostly excel when you get into fancier super steels with alloys where regular stones start to struggle. So how useful / needed they are depends a lot on the material in your knives.
Click to expand...

I don't have any super steels. I use diamonds for crappy stainless. Crappy stainless doesn't do particularly well with Japanese style whetstones. Much easier with oil stones or diamonds.
 
You must log in or register to reply here.

Latest posts

Back
Top