Torsion spring test

coop1957

coop1957

Joined
Oct 22, 2002
Messages
2,624
Recieved a new Kershaw Leek 1660 CKT on 1-3-11 and decided to do a test to see how many cycles before the torsion spring fails.
I drive a deliver route of 190 miles monday - friday. So I got plenty of time on my hands. I open the Leek 200 times per day. Not quickly, the spring does not heat up. Haven't taken it apart to lube.
So my math is 200 X 5 days a week x 10 weeks = 10,000 cycles.
Have not detected any weaking of the spring.
Not sure what the average time between failures is. Not sure what type of steel is used in the torsion springs.
I will keep close tabs and let you know when it fails.
 
the torsion bar in my shallot broke in 26 days. not too sure how many times i opened it... at least it was an easy fix.

look forward to see how long yours lasts.
 
probably not the best place to be opening and closing a knife 200 times a day, good luck though.
 
here is something strange.

My torsion bar in my cyclone broke while the knife was in my pocket. i went to sit on the floor and felt something jump in my pocket. The blade didnt open, i felt the torsion bar pop. I pulled my knife out immediately after and the AO was gone and the broken torsion bar was getting caught inside the hollowed out handle cavity. i removed the broken bar shortly after.

i am guilty of flicking open the knife just for the fun of it, but i was at work when the bar broke and i dont recall using the knife a lot that day. for some reason, it broke. but i probably got 2 or 3 years of life out of that torsion bar.
 
12,000 cycles. I have a new torsion bar at the ready, just for when it does break.
 
I've had a chive(same type of bar) since around 05 and i play with it constantly when im sitting around the house. It started noticing that the flipper wouldn't open it all the way and i would have to use the thumbstud. About the 3 months after that i finally heard the snap. I dont know how many times ive opened it but but 5+ years out of one spring isn't too bad especially considering how often i hear about other peoples breaking.
 
interesting test, but I think you're going to need a larger sample size. I had a brand new mini mojo "break" after just a month of light use, and I've had a dozen other knives last for 5+ years of substantial use.

The torsion bars are, overall, very resilient, but it seems like they're hit and miss. You get a good one and it'll last you a decade, you don't it'll last you three weeks.

But anyway, interesting stuff. Lol, but be careful playing with a knife while driving. I imagine that it would be hard to explain how you got stabbed by a knife during a fender bender lol.
 
I've had my Random Leek 1660 GRYST model for a year and open it about 20x's a day. I opened it once about 3 mos. ago for a cleaning and lube. Its still firing very hard - like new actually. Let's round it up to 7000 openings. :)
 
I have owned about 10 production auto or assisted folders and have never had a torsion bar fail...and I play with them ALOT.
I do have an incredible amount of faith in my Benchade's as well. Anyone ever witness the failure of a BM torsion bar?
 
My bad. I did call the torsion spring a torsion bar. It is a spring that compresses and expands. Benchmade Axis knives have two omega springs and yes they do occasionally break but when one breaks the other one ensures proper operation.
 
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