Chefknivestogo Forums

Re: this technique from 6:16-6:18
https://youtu.be/jWPI6IFKPFE?t=373

A chef buddy of mine told me to never 'rock and rotate' (is it clear what the technique is i'm talking about? If not i'll let me know and i'll try and clarify) a hard knife like he does at the end of this section because of the serious potential to chip the knife edge. Is this a moment of bad technique, or is my buddy over protective of his knives?

Welcome to some gray area. For many knives, rocking like this is in no way a bad technique; however, for some knives it is a potentially hazardous one. Hard, thin edges aren’t suitable to the lateral force that can happen where the edge turns on a board, particularly if too much force or a second hand on the spine is involved. Softer steel knives often excel in this area and are often designed with this technique in mind. With a careful hand it can be done without damage using any knife, or you can use push/pull motions instead to eliminate the chance of lateral force. I don’t fault your buddy for having reservations of other people using that technique. Anyone who’s ever fixed other people’s knives knows it’s a fairly common chip spot. The chances of damage certainly are real; however, the rule isn’t an absolute. There are people who treat knives like bludgeoning devices that can cause serious chips with the rock and rotate, typically these people are accustomed to dull knife shaped objects as opposed to knives.

Fwiw, if I’m ever needing an amount of minced herbs and using a hard, thin knife, my personal technique is to use push cuts as thin as possible through in a chiffonade manner, turn the product and repeat, and finish with a few light rock rock rocks at the very end. I’m still running the risk of damage with the motion but reducing the likelihood by using a different technique for the majority of the product. I’ve never personally experienced major damage from doing so; however, with other people’s knives I’d respect whatever boundaries they set.

Wow, thank you for the in depth answer. That makes sense to me; it sounds like he wasn't paranoid and I owe him a beer =D.

EDIT: Also, this is why I love this forum. Not only did a get a literal answer to my relatively amature question, I also got specific details as to when a method is valid or not and a good correction to a potentially poor technique. Just saved me 80$ in a knife skills class =)

Glad to help, let us know if you have more questions.

Let me second the advise on thin hard edges, I got careless in my technique and ended up with a 1.5-2mm chip. Knife was a perfect fit for this type of damage; single bevel gyuto with a 9-10d edge grind in a B1 steel. Never felt it happen but I think it may have stuck slightly in the end grain board and the lateral force when I rotated just took out a big piece. It took a long time to repair and cost me some height on the knife. I'm more careful now.
Ron

jmcnelly85 wrote: ↑Fri Jun 15, 2018 2:15 am ...particularly if too much force or a second hand on the spine is involved...

That is the biggest key, the second hand on the spine is when damage is most likely. I cringe when I see people put their off hand on the spine of any knife when they start rocking. Always avoid that second hand on the spine.

I've looked at the video several times, and I don't think it's poor technique. The blade is moved when only the tip is in contact with the board, nothing wrong with that. There is no torquing of the blade when the cut is executed, either. I think your buddy isn't looking at what is actually happening.

+1 jmcneally. Pretty much says it all.

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Ken