75 - HRc = DPS
And the answer is.....
75 - HRc = DPS = User application dependent.
Yes, soooo many variables play a role in balancing this equation, but the bottom line is user application dependent
Any tool, including knives, are designed to perform a certain function/s, and generally one would appreciate such tool to be tuned to deliver the ultimate performance.
With knives, this would imply that that the grind, geometry & edge angle are aligned to compliment performance.
Some users are very light in their application of the knife in question and may comfortably tweak edge angles so low that our eye brows touch our hairline.
On the opposite side of the spectrum there are those that are very hard on their edges & can damage the best of the best very rapidly.
Generally high HRc figures tend to be more "chippy" than lower HRc numbers - you all know this.
Lower HRc figures tend to be "tougher" - you all know this too.
So finding the "ideal" DPS for any HRc would depend on how the user applies/uses/abuses the particular knife in question.
When I get a new knife, I normally go though a trial & error process to tweak the edge to the point of failure during "MY APPLICATION/USE", then up it a notch - that would thus be my maximum performance point.
Now I could give this specific knife to a range of people, none of whom might find it suited for their use/application - some will up the edge angle & others may drop it even further.....again, there is no wrong or right here.
If it works for you, then stick to it - each person is unique, period.
Harder HRc steels can generally take & hold steeper edges than their softer counterparts.
Softer HRc steels can generally take more abuse than their harder counterparts.
Then just to confuse our minds there are those steels with relatively high HRc numbers, that are really quite tough as well - I reference specifically my Yoshikane SLD reported @ 64 HRc.
It has a true angle edge of 12 DPS and works for me.....but might not for you.....
I am no expert sharpener or professional by any means - my opinion expressed stems from personal experience only.
So yeah, without getting into "facts" & personal jubilation, I reckon one should approach this in the context intended by the OP, he gave the equation and asked....discuss...
Then please let's keep it civilized - you are all a great bunch of people & I learn daily from you - let us respect the opinion of others, even if you might disagree.
Oh, and by the way, my mind is clear - no man sodas yet...