Folder design with best lateral/prying strength

Thick tip and blade will help some. No folder is really made for prying, but being robust will resist snapping off a tip some . Most seem to break at the thumb stud or spyhole(or generic version), if not the tip ,so maybe a robust flipper. Better yet a replacement no matter what you do warranty.
Myself I would rather use a knife for cutting and pick up a prying tool for prying-right tool for the job

 

I can't believe nobody has mentioned it yet, but the big blade stops on an XM-18 should help it resist lateral force.

 

But you are.

What good would the strongest lock and frame be if it was paired with an Opinel's blade?

If you're designing for a specific purpose then all aspects must be considered or it will fall short of the goal.

 

While i dont pry with my folders, external stop pins and large washer pivot systems will help with strength against lateral forces along with a robust tip of course.

 

The reason lock strength and vertical force is talked about is because it directly relates to the function of the knife. If a knife lock cannot resist an amount of vertical force it has a risk of failing, resulting in injury to the user. Lateral force is not talked about because it is not related to the function of the knife, a knife is not intended to be pried with.

 

Tom brown tracker is a good prybar knife, since its a thick slab o steel.

It has awful cutting and slicing ability, awful chopping ability, useless serrations, but pry-power is excellent I bet

 

We can discuss this indefinitely, but the fact remains that a folding knife's vertical blade play can be boiled down to two criteria: Safety and Performance. A knife with a good deal of vertical blade play or weak lock up can slip its lock and fold on your fingers. This is why Lynn Thomson's guys make a big deal about doing pull ups on the knife to test the lock strength. A knife with a good deal of up and down play may disengage the lock. A blade wiggling from side to side would bug me a great deal. A knife snapping shut on me when it's not suppose to could ruin my day.

As for performance, this gets into the weeds of perception. Vertical blade play can make a knife "feel" like it's not doing the cutting job or requires extra effort. OTF autos have more blade play than would be acceptable for most knives simply due to the design. A $300 Microtech does not lock up as tight as my 12 year old $70 Endura. However, it is baked into the design. My Microtech cuts just fine, but when I bear down on it, I can feel it move a smidge.

There is actually a thread about blade play on the CRK forum. Probably the most exacting production knives out there in most regards. I believe someone mentioned a tolerance of .0005 or some such to account for the grease between the tang and washers. My Inkosi is dialed in to be smooth to open and close with no detectable up and down play and only the faintest side to side if I flex it hard enough to cut myself (which I did). I can crank it a touch tighter and it doesn't budge in the least. Maybe in a vice, but not using my arm strength. However, when I do that it opens like a wooden door with water damage.

I'm not sure you can reinforce a folding knife enough to make lateral play go away to the point where it is both undetectable and doesn't hinder the function of a knife. A solid frame of expertly milled and finished titanium using a ceramic bearing and washers tightened down by a big ol stainless screw and bushing comes about as close as I have held to "zero" lateral play.

 

Most are actually pretty stout but not the best for prying. Emerson may be the strongest - they seem designed for abuse.

 

A balisong would probably last longer prying than a typical folder but it would still be a bad idea. If I have to pry something I definitely don't reach for a knife.

 

If you are putting 100lbs of vertical force on a folding knife, in my opinion, you are doing one of two things: A) using the wrong tool for the job. Forcing the knife to work outside of its parameters instead of getting a stronger tool with more leverage that will do the same work with less effort. Which is just dangerous. Or B) frantically cutting/prying yourself or someone else out of a dire once in a lifetime event where thrashing the tool is the quickest/best option. It's not what the life is going to be doing for a living, it's just what you can reach in an emergency.

I still see lateral play as a prying issue which up to the end user to decide if that's something important they need in a folding knife. I have seen lateral tests where the blade lock up and scales flex sideways in a vice with a cheater, but this was shown how durable the knife was constructed and how much abuse it would take and pop back into spec and had nothing to so with attempting to limit said play.

Thinking of a knife that can fold and nearly behave like a fixed blade, the one that comes to mind is the Cold Steel Pocket Bushman. Once the RAM is engaged, there really isn't anywhere for the blade to move. The whole handle is rolled steel. So you have a solid piece of steel plunging into the tang and a monolithic grip. It might cut your fingers off when you try to close it and have the ergonomics of a piece of angle iron, but it's pretty solid.

 

Cold Steel folders with the Tri-ad lock are probably the overall strongest of any practical and affordable for "hard use" .

Their 4Max would probably do pretty good in any reasonable test . But most people don't want to carry something even that beefy for EDC .

To get increased lateral strength you'd have to go thicker and the market demand seem to be going opposite .

I consider the question to be perfectly valid and interesting .

So far as stabbing , if you mean flesh and blood , you don't need extreme strength for SD use . But you do need a lock that will stay locked = Tri-ad .

 

I don't know what kinds of things you want to use a folder for, but as Steely said it sounds like you're using the wrong tool. Folders marketed as "tough" are not do all indestructible, they are relatively tough compared to folders in general. And they certainly aren't fixed blade replacements, or prybar replacements for that matter.

 

I wouldn't try prying with any folder! but found the large pivot pin in the Inkosi along with CRK's excellent tolerances on titanium handles makes a Wonderfull work knife, absolutely no side to side movement what so ever, but most people would use a Crowbar for prying things.

 

Folders have maintenance and sanitary concerns that also make them less popular for hard use / survival .

Fixed blades are cleaner and less costly at any given level of performance .