Thread: Zowada Website - double bevel info. updated

"I think it would be in BIC's interest to produce blades that cut very comfortably and dull rather quickly. I believe the days that engineers in large multinational firms were actually trying to design something to make it better are long gone. I'm pretty sure the major concern is cost-effectiveness and short term profit. I bet they even conduct tests to make sure that those blades don't stay sharp longer than the marketing division has instructed."

So the double/triple bevels that they spent precious time and money on researching provide a smoother shave? Because then great, we agree on one point. (but not really for the same reason)

And no matter which way you look at it (slicing, guillotining, chopping) on the scale that we are dealing with, the metal composition (and heat treatment/tempering thereof) would play much more of a role than the double bevel in making the blade dull more rapidly. So quicker degradation is not a logical result of the double bevel in this case. It would save them much more to skimp on quality of materials than to spend money grinding double and triple bevels to get the same resultant decreased working time.


"My initial point was that one can draw two graphical curves for each bevel angle when one was to conduct standardized lab tests: one graph that would illustrate decreasing bevel sturdiness with a decreasing (acuter) angle and one graph that would illustrate increasing bevel stress exerted by the material being cut with an increasing (obtuser) angle.
For each given material there is a given point where the best of both worlds meets up. "


But, if things were to work as you claim then both of these graphs would have a similar curvature, like the graph of Ax^2 and Bx^2, both curves are x^2 but are altered by an arbitrary constant, A or B. They would start at 0 and move in a smooth curve up to some asymptotic position or linear slope. More than likely though they'd be different translations of a portion of the sine wave and still separated by some arbitrary constant, which means they wouldn't cross.

And those types of tests are done routinely to determine the best angle to put on a cutting utensil, there just isn't a quantitative point where the graphs cross, the variables have to be weighed in terms of functionality, durability, cost to produce etc.


"In the end I trust the engineers that designed razors for those lustrous brands like Puma, Dubl'Duck, Thiers-Issard, Dorko and others more then I trust those at BIC."


This is a logical inconsistency because they didn't "design the razors", the design was in already place, so it is not a basis for determining whether or not they were correct. And it has no bearing on whether or not BIC's design and the double bevel in general can hold an edge longer. But, if in fact the "traditional design" turns out to be the superior, excellent! I'll re-adopt it.



"In the end I don't think the slight angle increase that Tim Zowada suggests would make much difference. I just don't think that you could conclusively say that the edge would last longer, just for the reason that the bevel is a little obtuser. And I'm pretty sure that it would not be sharper than a properly honed edge with a single bevel."


The argument is not that one or the other is sharper, they would essentially be the same, as the edge can only be as fine as the grit used to polish it. But the double bevel ought to be more resistant to abrasion (chipping really, on the scales we are concerned with) because the cross sectional area would be differentially greater. A=[2x^2(tan(angle~7deg.))].

This argument is like someone saying "my face won't tolerate even the slightest micro chip in the edge." While that statement has a good deal of validity, the truth is that you will never be without some degree of micro chipping, it just depends on the scale you are talking about. The same applies to this. At some point yes, an obtuse angle hinders performance, but at some point it can only help, just like the micro serrations of .5 CrO help to cut through hair, but are too small to be felt by the skin.

BTW I think this is great that we are really getting into the fine details of cutting edges, I wish we could have some more people weigh in with their expertise. It's good to debate, things, life becomes much more interesting with alternate opinions and viewpoints.