I was looking at a couple of my knives the other day and got to thinking about lateral strength. What I was looking as specifically were the S5 and the WarDog. Now the S5 is 3/16 inch thick and the WD is .200 BUT it is a ffg whereas the S5 is a conventional sabre ground blade we are all used to.

Now Which one do you think would have the greatest lateral strength, meaning which one do you would think would break first if pried on sideways?

Now this thread isn't limited to just these two knives, but It's what I was thinking about at the time. Oh I guess I need to specify that the S5 is SR101 and the WarDog is INFI.

And YES, we all know that knives aren't pry bars. BUT we also know we all do pry with them.

Randy, I had to get through a piece of fairly thick wood with a holesaw, it was about 1,5 as thick as the saw thingy. I went one deep and had to get the wood out, I had ffd AD and Rat Shaker on me.
AD was flexing to the point I was afraid to push any more, RS just popped the wooden ring off just like that, no flex and no stress for me.

I would bet on Infi,with its superior heat treat.

I would expect the thicker (albeit FFG) INFI to have greater lateral strength, but you've not listed another determining factor...blade height.

The majority of strength of steel is dependent in the direction of load (this is why "I" beams are not "H" beams....which by the way are called "wide flange" in the trade). However, there are more dynamic factors involved than just shear unless you're applying the forces perfectly perpendicular to the axis with calibrated laboratory equipment (with fixed ends). In short, prying also induces (bending) moment. Bending moment is resisted differently than shear stresses.

If you graphically charted the shear stress you'd see a steady "force" with a perpendicular "break" followed by steady/even stress.

If you graphically charted the bending moment you'd see a parabola that increased until failure.

The fact that prying is a cantilevered non-hinge force complicates things a little too.

I'm busy today at work, and not explaining these principles well. This diagram should clarify...

All told, I'd GUESS they would perform similarly given thicker INFI has greater yield strength, but the "taller" S5 blade could help resist bending moment.

These are just my uneducated guesses.

They're both covered by the same warranty...no sweat.

UNEDUCATED! Your "drawings" look like a beanie hat with a propeller on top. Now THAT'S uneducated! (Meaning ME)

I think that I do understand what you're saying though.