are all torsion bars created equal?

S

s.c.

Joined
Mar 2, 2003
Messages
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I've had a chive break on me after repeated uses...probably wasn't from the absolute number of times I opened it, but the fact that I opened/closed it repeatedly, thus heating up the spring. I was actually surprised it lasted as long as it did, and content with the life of the torsion bar. I have a Leek that's going several years strong with no problems, and I played with that thing incessantly as well.

However, my mini-cylone torsion bar failed within 10 days of normal usage. The novelty of speed-safe is gone, so I didn't obsessively play with it. (it was replaced by kershaw, btw). While that knife was at kershaw warranty, my ZDP/Ti mini-cyclone failed within 3 weeks. Admittedly, I did 'play' with that one more, but it was definitley a premature failure.

So, are all torsion bars (from different models) created equal? Are some models prone to failure? If so, which ones? Does Kershaw keep stats on such things? Any input would be greatly appreciated.
 
I have only had 1 torsion bar break and that was on a leek that was a several years old, I called Kershaw and I had a replacement torsion bar a few days later.
 
Antihero17 said:
I have only had 1 torsion bar break and that was on a leek that was a several years old, I called Kershaw and I had a replacement torsion bar a few days later.
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Same here.

Kershaw tests there torsion bars to 10,000 cycles.
Think you just got unlucky with a couple.
I think this is the 1st post I've seen about a broken torsion bar on a Cyclone.
And as much as they get talked about.....that's saying a lot.
 
The torsion bar on my leek broke within a month.

I was considering sending it in for warranty fix, but I'm not sure it is worth the hassle.

I like this knife so much that I just use it without the speedsafe
 
i have only had one speedsafe fail on me and it was on the mini-zdp cyclone. however i used that to much more than 10000 openings and within two months it snapped. they sent me a new one and after a thorough cleaning and some militec i went back to work with it....that being said it is kind of sluggish again....i hope i didnt opening it another 10000 times hehe
 
riffraff said:
Huh?!? Exactly how many times per second are you able open and close a knife? :eek: :rolleyes:
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about 1.4 times per second :p

I think it would be safe to assume that opening and closing the knife 1000times in an hour while mindlessly watching t.v. would stress the bar much more than opening it once a day over 1000 days. Why is that? Did you ever do an experiment in grade school where you bend a paperclip or other piece of wire repeatedly to get it to warm up? I'm not saying I do it so fast that there's smoke coming from my knife, but surely obsessive knifesturbation will heat and weaken the torsion bar.
 
Ok, someone correct me if I'm wrong on this, but my understanding is the heat generated is pretty irrelevant.

When you bend a paperclip back and forth, you work-harden the steel on the inside of each bend. You bend it and one side compresses, then when you unbend it and bend it the other way the compressed side doesn't expand back, you just compress the other side. As you do it it becomes more and more brittle until it breaks.

Take a paperclip and bend it one way, then sit it down and 5 minutes / an hour / a day later unbend it and bend it the other way. It should break after about the same number of bends. I think you're scale is off (and not by a factor of a couple, but more like a couple orders of magnitude) regarding how fast you'd have to be bending the thing to generate significant enough heat levels to cause failure.
 
The original torsion bars in the min-cyclones (Ti and standard) - had a ground out portion in them - the replacements do not . My guess is the lack of the ground out portion probably will make the replacements last noticably longer. Having said that - if you're flicking any knife open and closed constantly - ahh - hell -I'd just be startin somethin -so.
 
s.c. said:
[...]but surely obsessive knifesturbation will heat and weaken the torsion bar.
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Weaken it, maybe. Heat it, not a chance. You could heat the torsion bar with a flame and it wouldn't create enough heat to affect the spring's temper (which would be the only way heat could affect it).

Methinks you just got a bad one. It happens.
 
I have no doubt that I got a bad one, but it was the coincidence of having two mini-cylones fail within a month that got me thinking if some models were more prone to failure.
 
I have a 1660st and my speedsafe only opens it halfway and i have to pull it the rest. Is there any way I can fix it without sending it in for service? I couldn't if I wanted to, i'm not the original owner and don't have the receipt.
 
Welcome Brian!

First, about Kershaw's warranty. They warranty the knife, not the buyer, so no receipt is necessary. Their CS is first class, and will help you with those things that can't be fixed by yourself. Someone recently mentioned here that they ordered some parts for their Kershaw, and had them in one week. Normal, you say? They were in Australia!

As for the sluggish SpeedSafe, I'd suggest taking the knife apart and cleaning and re-lubing it. It's not hard to do. WD-40 or Hoppes Solvent makes an excellent cleaner, and Mil-Tec or Hoppes #9 Gun Oil will work as a lube. Use it sparingly. Make sure to have a little dab of grease on hand to put in the spring cavity. This helps cut down on potential rattling issues. That should do the trick. If not, then a replacement torsion bar and PB washers from Kershaw will fix it.

Just remember to make a mental note of where each piece goes, and before you start to remove the handle, make sure the blade is fully open!

It's really not a biggie. You can do it!
 
SPXTrader said:
It's really not a biggie. You can do it!
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Exactly. If you have ever put a model car together, that's like rocket science
compared to taking a Leek apart. Once you get her open, you'll see just how
simple it is.

And as SPX said, Kershaws CS is top notch.
Australia, In one week!!....That's something to think about
when you go buy another knife. :thumbup:

Welcome to the forums.

SV
 
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