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Bevel angle rule of thumb?

Tue Mar 25, 2014 11:20 pm

This came to me as I drifted off to sleep last night.

75 - HRc = DPS

Discuss.

Re: Bevel angle rule of thumb?

Tue Mar 25, 2014 11:30 pm

Sharp = Sharp

Re: Bevel angle rule of thumb?

Tue Mar 25, 2014 11:45 pm

I don't think the HRC dictates what you are using the knife for or how you use it. One person may use a knife, of the same HRC, completely different than another.

Not to mention the knife's intended purpose. A Gyuto is much different than a petty is much different than a suji.

Mowgs

Re: Bevel angle rule of thumb?

Tue Mar 25, 2014 11:55 pm

Jeff B wrote:Sharp = Sharp

+1

Re: Bevel angle rule of thumb?

Wed Mar 26, 2014 2:16 am

The hardness does dictate what a knife can be used for and how it can be sharpened.


As for the formula above I don't see how it translates to anything.

Re: Bevel angle rule of thumb?

Wed Mar 26, 2014 3:37 am

What drove this was a PM discussion early yesterday about bevel angles and it got me thinking

In general, and as a starting point, what bevel angle would you put on a Rc 65 HAP40 blade? Rc 63 Aogami Super? Rc 60 AEB-L? Rc 57 German stainless?

Obviously pettys and slicers that don't see impact can be sharpened somewhat more acutely. And anyone sharpening a yanagiba likely isn't even thinking about the bevel angle.

Re: Bevel angle rule of thumb?

Wed Mar 26, 2014 4:33 am

I like this question. I'd like to answer it by a poem of sorts...

"Bevels are like beer. They come in all shapes and flavors. They all have a place."

I teach physics, not English. Best I could do.

Re: Bevel angle rule of thumb?

Wed Mar 26, 2014 4:37 am

The bevel angle should always be the lowest a blade can handle for the cutting tasks it will perform. It could mean that every steel and hardness you named were all sharpened at the same angle just finished at different grits. Thinner blades are often sharpened to thicker angles for edge support while thicker blades are sharpened thinner trying to compensate for poor geometry.

The main advantage of hardness is the ability for a edge to hold sharpness and higher levels of refinement longer. Once you start talking about high alloy steels then it becomes a individual subject that is no longer simple or comparable.

Re: Bevel angle rule of thumb?

Wed Mar 26, 2014 4:44 am

I believe too many factors are being left out of play. AEBL and AS are going to each take a more acute angle(respectively) than the other two. AS will hold a slightly more obtuse angle longer, than aebl but getting to that angle makes hap40 a huge competitor. This is all assuming proper heattreat on all steels to their specific nature.

I have aebl by dt and a hap 40 gyuto currently. Used blue steel by many makers, never super tho. When I sharpen the kohetsu for the first time and give it a real work out I'll get back to you.

Re: Bevel angle rule of thumb?

Wed Mar 26, 2014 6:26 am

Sorry Jason but I strongly disagree. No matter what kind of steel is used the individual user is going to have a strong personal preference for one kind of edge steepness or bevel geometry.

Is it not an individual subject of any steel regardless of super duper alloys? What makes it not comparable? It's all subjective BS really. Some people think Cutco is super steel :)

If the object of using powdered metal steels is ultimately edge retention it would make sense to convex the hell out of them and beat the hell out of them :)
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