Found a task that S110V is NOT good for

[Strong-Dog]

1095 at 62-63 RC isn't going to bend very much before it snaps..... Given the same geometry...

Now yeah at 55-59 RC with a spring temper yeah it will bend more before it breaks.... But it will still break, it will just take longer....

1095 with a Differential Heat Treatment like the ABS guys do it will bend a lot more, but the edge will crack because it's a lot harder than the spine...

At 55-59, at what amount of force will it permanently bend? Would it take more force to permanently bend a softer blade, or break a harder blade?

[senorsquare]

Hola Senor,

Perhaps you can send it to me and let us check it out?

sal

Will do. Any particular address or Attn I need to send it to?

[gbelleh]

Sorry to see that!
Here's an idea, just lay off the beer for a little while until you make your $100 back. You'll get another S110V Manix 2, and your other knives will be safe in the meantime. :D

[Ankerson]

At 55-59, at what amount of force will it permanently bend? Would it take more force to permanently bend a softer blade, or break a harder blade?

It would depend on the actual HT and tempering process.... How much spring temper it has.

[Pinetreebbs]

Donate that body for science.

[ZL1]

Sorry to see that!
Here's an idea, just lay off the beer for a little while until you make your $100 back. You'll get another S110V Manix 2, and your other knives will be safe in the meantime. :D

That sounds more painful than breaking his knife!

[paladin]

...



The blade is still firmly wedged in the log. I'll have to use a splitting wedge to get it out....

Good call Senor!

I wasn't looking forward to your next thread...

"How I wrecked my Tuff trying to rescue my broken Manix" :rolleyes:

But seriously, thanks for sharing! :spyder: :D

[arty]

The Manix is a pocket knife. When splitting wood, a hatchet or small axe will do the job. That said, I saw a workman
Break the hickory handle of a 16oz hammer when trying to lever up some wood in repairing my subfloor. You can break anything, if You are strong enough. The FRN seems to be strong stuff, since it held up while the blade snapped.

[Officer Gigglez]

I expect there will be memorial services? I mean, sometimes we lose loved ones, but life goes on.

[Scorpion]

Hey, why can't this be a thing? Destruction tests, like with the iPhones. Tons of you guys have more money then you know what do with judging by the pics of your collections, so why not? We certainly enjoyed this thread, and sal can get an idea of how strong certain steels are without putting himself in harms way. (/sarcasm..or is it?)

[opusxpn]

Sorry about your knife, it is a shame. Mr. Sal wants to see it he is going to really look into its design and he will change it and improve it, not for splitting wood of course, for that get an ax or at least a machete :D . Well at least Cliff gave you an idea it would make a nice paring knife.

[twinboysdad]

Honestly, I love that you did this. Better to break it having fun than taking it out and fondle it like the gimp in pulp fiction and put it back in its box. Safe queens are for losers :p

[sal]

Will do. Any particular address or Attn I need to send it to?

Send it to:

Spyderco
Attn: Sal Glesser
820 Spyderco Way
Golden, Colorado 80403

thanx,

sal

[phillipsted]

On the bright side, this is now the *perfect* knife to carry with you the next time you visit New York City. The Police can't give you a ticket for carrying a knife with no blade!

TedP

[bdblue]

At 55-59, at what amount of force will it permanently bend? Would it take more force to permanently bend a softer blade, or break a harder blade?

OK, some crude generalizations here- hardness of a steel is roughly a measure of its yield strength, more heat treat increases the strength of the steel. As an example common steel used in the construction industry, car bodies, etc. has a yield strength of at least 50-60 ksi and is not heat treated. Higher grades of structural steel do have some heat treat, and I've heard that some older armor plate used by the military is heat treated steel. At the top end is steel used in prestressing, with strengths of 240-270 ksi. I think this is getting into the range of steel used in knives, I once picked up a piece of 1/4" diameter 240 ksi prestress wire and I was going to make a screwdriver bit out of it. I could not scratch it with a file, but I was able to cut and shape it with a bench grinder.

As steel gets stronger it is usually less ductile. You can bend a piece of coathanger wire back and forth and it will not break. I have some pieces of PT strand that are not much larger than heavy coathanger wire. They are much harder to bend, but after bending them a small amount they fracture.

Rc is measured by putting a small dimple in the surface of the steel, essentially yielding the steel, so it is a direct measure of strength. Theoretically 1095 at Rc 59 is about the same strength as M4 at Rc 59. I have some question about how the carbides in steels like S110V affect its Rc measurements vs. actual strength. I think where the metallurgy of more exotic steels helps is in providing increased wear resistance and increased ductility or toughness, at the same level of hardness. I've read where some steels such as K390 allow for high hardness without being prone to chipping, wheras something like 1095 if heated to a very high Rc would chip too much in use.

So put those 2 principles together- a blade with low Rc will reach a yield point at lower than a blade that has a high Rc. As you start to pull sideways on the handle, the lower Rc will start to bend before the higher Rc will. Now assuming that the lower Rc is more ductile, it will deform more before it actually fractures. The higher Rc will resist more load, but will reach its breaking point before it deforms very far and will fracture. This behavior will be most obvious in a smooth bar of steel. There are many more variables than this, including the shape of the blade. The metallurgy and heat treat will influence the steel's notch toughness which would be more applicable to something like a knife blade that has curves, notches, maybe holes.

I looked back at the blade photos in this thread. The broken blade failed through the tiny hole next to the pivot hole. I am guessing that the clamping of the pivot limited the bending in the tang at the location of the pivot hole. There should have been a little more bending in the tang at the location of the tiny hole, and with the tiny hole acting as a stress concentration I'm guessing that is why it fractured there. A steel with a little more ductility could sustain high stresses around the small hole without starting a fracture. I'm guessing that a steel like S110V is a very strong steel, but trades off ductility and fracture toughness for strength and wear resistance.

http://www.bladeforums.com/forums/showt ... st13474477

I've read a little bit about carbides formed in stainless steel. I'm wondering how these affect strength and toughness, maybe all of the embedded carbides act like tiny little stress concentrations within the steel, providing the tradeoff of less ductility along with more wear resistance.

I'm a structural engineer so I know more than a little about stresses, bending, stress-strain properties of materials, even fatigue and fracture, but I'm not a metallurgist so I don't know how some of the alloying elements in different steels affect these properties. Not being a metallurgist I might have said something that would make a real metallurgist cringe. If so they can tell me to stick with stress analysis.

[bdblue]

Perhaps you can send it to me and let us check it out?

Could I make a suggestion?
Not knowing how you actually do test knives, could I suggest that you test some of the S110V blades in lateral bending compared to the S30V blades, or maybe make up some of the S110V blades without the little hole and test them in bending. I'm curious if the stress concentrations around the little hole combined with the properties of S110V are detrimental to the blade. I've read before that the little holes are used to mark blades of different materials, maybe you could devise some other way to mark the blades.

[FarmerTed]

Hold my beer and watch this!

[chuck_roxas45]

Condolences Senor...

[Blerv]

Sorry Señor. What a bummer.

[Johnnie1801]

**** Senor, I hope the gods of Spyderco's past, present and future forgive you for this. Perhaps a pilgrimage to Spyderco HQ in Golden is in order, at least you can go home with a few new purchases, lol.

I just hope Eric Glesser doesn't find this thread. As the designer of this knife, death by a thousand cuts could be the least of your worries, hahaha.