Issue sharpening knife with flex on Sharpmaker

B

Brew-Jitsu

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Oct 22, 2012
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So, I'm in possession of a knife that I am supposed to sharpen for my sister-in-law. Normally I have no issue putting an edge on any knife using my Sharpmarker, but this 8" Zwilling Henckels slicer has a lot of flex to it and tends to bend unless the pressure is so light that it's hardly removing material. I've tried holding the knife in a few different ways, but they weren't effective (and probably not too safe).

I'm hoping someone has some suggestions using a Sharpmaker on a blade that wiggles as much as this one does. Thanks!
 
Alex, I have sharpened fillet knives that do the same thing. The key is to use the medium stones, slow and steady should do the trick. Light pressure is all that should be required, but you will end up doubling the amount of swipes.
 
When only supporting the knife by the handle, as when sharpening on the SM, the need for feather-light pressure also dictates a much more aggressive abrasive is needed. For blades like this, diamond rods will still remove material quickly, with just feather-light strokes. Diamond rods have almost become the default for me, when sharpening flexible blades on devices like the SM.

The alternative is to sharpen in more conventional 'freehand' fashion, using conventional benchstones and supporting or backing the flexible tip of the blade with your 'off' hand, to regulate the angle and pressure in specific areas of the edge.


David
 
RevDevil said:
Alex, I have sharpened fillet knives that do the same thing. The key is to use the medium stones, slow and steady should do the trick. Light pressure is all that should be required, but you will end up doubling the amount of swipes.
Click to expand...

Thanks for the tip! I will definitely try that.
 
Obsessed with Edges said:
When only supporting the knife by the handle, as when sharpening on the SM, the need for feather-light pressure also dictates a much more aggressive abrasive is needed. For blades like this, diamond rods will still remove material quickly, with just feather-light strokes. Diamond rods have almost become the default for me, when sharpening flexible blades on devices like the SM.

The alternative is to sharpen in more conventional 'freehand' fashion, using conventional benchstones and supporting or backing the flexible tip of the blade with your 'off' hand, to regulate the angle and pressure in specific areas of the edge.


David
Click to expand...

Using traditional stones definitely crossed my mind. I no longer own any, but maybe I should pick one up for cases like this.
 
Grit No I don't thinkso. It flattens the edge takes all the nicks out.don't actually sharpen. In other words it just refins the steel.
 
AlexWitte said:
I thought steels were more for honing than sharpening? Is a steel equivalent to a particular grit size?
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The grooved steels can be extremely aggressive on softer blades, like a coarse file. Smooth steels without the grooves do little more than realign or burnish (polish) the edge, which won't help much if the apex is already dull. Between the two types, sort of opposite ends of the spectrum in aggressiveness. The grooved steels will also raise a big burr in a single pass; more so, if pressure is heavy. I have a tiny little 'Sheffield' grooved steel that came with a Victorinox SAK, and the working length is about 3", maybe less. Even so, it has never ceased to amaze me how easily it'll raise a big, honkin' burr on an edge, in only one or two passes. If you get your 'touch' in tune with one of these, they can be handy on simple kitchen knives. I'd not want to use them on better blades, because they're so coarse. Harder blades might be chipped on them.


David
 
Jason B. said:
A benchstone is your best option.
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I think I have a DMT EF "stone" (plastic base) that I could use. I'm getting results with the Sharpmaker, but it's uneven, but the edge also came uneven in the same areas. It's a learning experience for sure.
 
For kitchen knives that need more than a regular steel I use a Wusthof diamond-steel.
I find using the oval steel like that one works extremely well even with very thin blades that have bent/wavy edges from someone twisting while cutting(abuse).

I agree on using the benchstones if the edge is uneven to start with.
 
The main issue here is flex and without using a stone and both hands to sharpen you will never be able to apply the proper amounts of pressure to the edge. When sharpening a knife with this much flex you literally have to flex the blade into the stone when sharpening in order to prevent uneven bevel lines. It will feel wired but work wonders.
 
Obsessed with Edges said:
The grooved steels can be extremely aggressive on softer blades, like a coarse file. Smooth steels without the grooves do little more than realign or burnish (polish) the edge, which won't help much if the apex is already dull. Between the two types, sort of opposite ends of the spectrum in aggressiveness. The grooved steels will also raise a big burr in a single pass; more so, if pressure is heavy. I have a tiny little 'Sheffield' grooved steel that came with a Victorinox SAK, and the working length is about 3", maybe less. Even so, it has never ceased to amaze me how easily it'll raise a big, honkin' burr on an edge, in only one or two passes. If you get your 'touch' in tune with one of these, they can be handy on simple kitchen knives. I'd not want to use them on better blades, because they're so coarse. Harder blades might be chipped on them.


David
Click to expand...

A butchers steel's job these days is honing or realigning the edge. When they, " The Europeans " made carbon steel blades that were a little softer these steels would work like a file a put a crude but serviceable edge on culinary and other carbon steel knives. These carbons steel blades are about a 54-56RC

With modern stainless steels having an abrasive resistant quality and the knives being HTed to a rockwell of 57-59RC, the heavy lined steels really just tear the edge up and its worst on Japanese culinary knives which can be up to a 62-64 RC.

I polish these butchers steels to 600 grit for many of my customers, which it the grit I finish sharpening with so these then hone or realign the edge just right or I suggest that they get a Diamond coated butchers steel. Even after you wear all of the diamond off they will work fine for honing any of your cutlery.

What RevDevil said for a sharpening technique should work fine.
 
I googled that slicer and it doesn't seem like it would flex much at all. But I've probably got the wrong blade and of course I *believe* you that it flexes! I've had similar experience with very thin blades and just don't use the SharpMaker with them any more. At least not much.

Before I got really comfortable with the SharpMaker, I thought doing long blades (more than around 5") was awkward because of the various pressures and the length of the stroke I had to make, all while trying to keep the blade aligned in 2 dimensions, while pulling backward at the same time. As a way of making this easier, I bought a screw adjustable C clamp for about $3 at Harbor Freight, and used it to clamp the SharpMaker to a table. Then I'd hold the long blade with the handle in one hand, and my other hand guiding the other end of the blade. This improved stability dramatically, but required me to switch hands when I switched sides, otherwise my off hand would be in a funny position on one side.

I'd like to tell you how this is SUCH a great method and how I used it on a kabillion knives... but the truth is I only experimented with it on a handful of blades. Now I'm ok sharpening 9+ inch blades on the SharpMaker with just one hand on the blade and the other holding the SM in place.

Honestly though, I only use the SM for touch ups or minor sharpening. When it goes beyond medium dull, I break out stones, or the WorkSharp Ken Onion every time. The SM can only do so much with the medium triangle rods.

Good luck to you!

Brian.
 
Use the corners. In the SM's instructional video, Sal sharpens a filet knife using only the corners of the stones. He skips the flats.
 
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