Folders Vs. Fixed Blades; A question of strength

Again, that's what I'm saying. Design issues.

We're not discussing existing locks, we're discussing possibilities.

Anyway, a pivot pin needn't be thin, and a stop pin isn't the only way to do a blade stop. As I pointed out, many navajas have a bladestop that is integral to their handle, and the handle can easily be made in one piece by stamping or machining. Material can be titanium or steel, or anything else you want.

You have two surfaces contacting the bladestop; the first is a section of tang that lies flat against the handle, paralel to the edge; the second is a protrusion that's sticking out at 90 degrees and makes contact agaist the upper bolster or "tip" of the handle. This will serve to bleed out a lot of the force being transmitted to the pivot pin. The bladestop is inherently stronger than you could break by hand.

You'd have a hard time snapping a .25 inch pivot pin of good steel. And actualy, that pin could be made integral with the blade for greater strength and mitigating effects of breakage.

Let's not forget "the right tool for the right job" in this discussion. We're talking about a knife, not a chisel or hatchet. I think many folders are more then strong enough for the job of cutting reasonable materials. In most cases, if you caused a well designed, quality folder to fail, you were using the wrong tool for the job. The knife community is swinging over into fixed blades once again, and that's fine, but from a practical standpoint, it's kind of like women's clothing: trends in fashion. Of course a solid bar of steel is stronger then several pieces pinned together, but for most "normal" cutting chores (as opposed to prying or digging etc.) a good folder is strong enough. If I needed a "survival," combat, or fighting knife, I'd go with a fixed blade because these activities can abuse a knife. Otherwise, I stick with a folder. Remember, a knife is primarily about a sharp cutting edge, not an iron pry bar.
Oh, OK Snickersnee, the light finally came on. Sorry. There are knives like the Benchmade Sentinel and Gerber Covert where the blade stops against the liners themselves. This would seem stronger. You probably would break it outright. Over days and weeks of really hard use though, you would get wear in those parts that meet each other. Tolerances would increase, locks would develop some slop. Eventually a person might consider the knife worn out. That would most likely never happen to a fixed blade.

I realize that is probably not what you meant by strength when you started the thread though. I agree there are certain folders that one would probably never break doing a single cutting chore, and one could posit that that makes them strong enough. Ultimately though, the full tang fixed blade must win out.

Over a prolonged period of time a fixed blade would win out in that regard. Most likely. A folder certainly wouldn't be able to surpass the fixed blade.

However, depending on how the parts interact, and wether or not the design is made with replacable bearings or somesuch, it may take extreme use to get that lock sloppy. And even then, depending on the design of the lock, it may not matter.

But that's endurance, not strength, as you observed. Considering folders are a convenience tool that are seldom the choice for truly heavy duty anyway, it's a situation that will take a long time to appear.

A solution would be to make the blade the part that wears, since it would likely be the easiest part to replace.