Trouble Sharpening a 10YO Sabatier Kitchen Knife

[peanutaxis]

Hi Guys,

Thanks in advance. I can sharpen my Wusthofs and Japanese knives pretty well but I'm struggling to sharpen a Sabatier 6'' chef's knife.
What keeps happening is that after it gets used even only a little bit it develops what I would describe as a burr on both sides. I assume that what is happening is that - because it is softer steel than I'm used to - I am not removing the burr properly; when I do my burr removal maybe the burr is just standing up straight and seeming sharp, but with use it just gets mashed down and so it feels like a burr on both sides. I am sharpening on a Sharpal 325->1200 diamond plate. The last time I sharpened it I increased the angle to 20° on each side and then did many - like 50 each side - of burr removal strokes, but only very lightly. But the problem still happened.

I'm wondering if what I'm doing wrong is that you really need to start burr removal strokes at sharpening pressure and then gradually reduce them, whereas I went straight to very light strokes. Or maybe I'm way off track.

Thanks for the help,
p

 

[Obsessed with Edges]

What sort of cutting surface is the knife being used on? Sounds like it's hard enough that it's flattening and mushrooming the apex of the edge. That would create the burr-like effect on both sides of the flattened apex. Either the steel near the edge is much too soft to be durable, or the cutting surface used is much too hard for the edge.

It's possible there is a standing burr, as you mentioned. But ordinarily, if it's there, it would more likely just get rolled to one side or the other.

A family member of mine used to use a paring knife to section an apple on a ceramic tile countertop, pressing the blade through until it smacked hard against the tile. And predictably, the edge would get that flattened, mushroomed apex as a result. But that's the only time I've seen that sort of damage on a knife's edge.

 

[peanutaxis]

What sort of cutting surface is the knife being used on? Sounds like it's hard enough that it's flattening and mushrooming the apex of the edge. That would create the burr-like effect on both sides of the flattened apex. Either the steel near the edge is much too soft to be durable, or the cutting surface used is much too hard for the edge.

It's possible there is a standing burr, as you mentioned. But ordinarily, if it's there, it would more likely just get rolled to one side or the other.

A family member of mine used to use a paring knife to section an apple on a ceramic tile countertop, pressing the blade through until it smacked hard against the tile. And predictably, the edge would get that flattened, mushroomed apex as a result. But that's the only time I've seen that sort of damage on a knife's edge.

Thanks OwE. Yes I checked with the owner and they say they are only using it on their end-grain wooden board and not their marble benchtops. I plan to re-sharpen and use it heavily in my kitchen and see what happens. Do you have an opinion on the angle I am using, given that the internet tells me that Sabatier is HRC = 54-56? Thanks.

 

[Obsessed with Edges]

Thanks OwE. Yes I checked with the owner and they say they are only using it on their end-grain wooden board and not their marble benchtops. I plan to re-sharpen and use it heavily in my kitchen and see what happens. Do you have an opinion on the angle I am using, given that the internet tells me that Sabatier is HRC = 54-56? Thanks.

I think for the time being, the angle you've chosen (20° per side) should be OK for most any kitchen knife in that hardness range.

Another thought occurred to me yesterday. If for some reason, the knife had previously experienced some heat damage to the steel, as by powered grinding or whatever, then weird issues like you described could be possible until the heat-damaged steel is finally ground away near the edge. I've had one or two knives with strange issues like this, with very unstable steel near the edge. It took many resharpenings over time (weeks or months) to get rid of the weakened steel at the edge, after which they finally started behaving normally in typical uses. So, if you continue to see this odd behavior from the edge, it might just take some time to sort it out.

 

[Gottagofishn]

In regards to stropping...
I find the steel and hardness mostly determine the pressure needed and abrasive type when stropping. For example, Bucks seem to develop a hard burr for me. I use more pressure and a higher angle the first couple of passes, always finishing with very little pressure and the exact or very close (+.2) to the edge angle to finish.
Some stainless burrs just fights you all the way.