Leaving a single blade, Slipjoint joint knife blade always opening for displaying - bad idea?

M

minibus93

Joined
Dec 30, 2021
Messages
9
Hello,

I have a Slipjoint knife that has only one blade (it's not one of those multi tools). It also has a 30 degre half safety stop, but I would like to keep the blade always fully open for displaying purposes

Is it a bad idea? The knife isn't sharp and not really pointy so it wouldn't be a threat, I'm more wondering about damage to the knife itself or the spring...
 
Springs are worn through use. The only time a back spring is experiencing tension and flex is when it overcoming that tension to hold it open or closed or at the half stop.

The only danger is, as you said, the knife being free and open. There is next to no chance of it damaging the knife.
 
It shouldn't be a problem, as mentioned. Only other advice I'd give is oil the springs and inside of the knife periodically. I've seen opened knives on display develop a surprising amount of rust on the inner springs sometimes.
 
Steely_Gunz said:
Springs are worn through use. The only time a back spring is experiencing tension and flex is when it overcoming that tension to hold it open or closed or at the half stop.

The only danger is, as you said, the knife being free and open. There is next to no chance of it damaging the knife.
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Thanks!
 
The spring is at the exact same tension in open and closed postion. No problem whatsoever.
As others have said a well designed spring only sees "use" when it is in active bending.

I'm an engineer with a heavy background in material science. Springs fascinate me. Only Steel and titanium have the potential to have something called infinite life. A properly designed steel spring can actually be flexed (within it's design parameters) an infinite amount of times and never break. Unfortunately most springs are not "properly" designed, and all high performance springs (such as in a slip joint) are intentionally not designed for infinite life because it would require a very long handle, but steel (iron) is ironically the best element to make springs out of and we happen to have them on most every slip joint!

The scary side to infinite life is that materials such as aluminum cannot achieve it. The aluminum that your plane, car, and bicycle are made out of will eventually fail 100% of the time under any stress...
 
Macchina said:
. Springs fascinate me. .
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One afternoon I had a fascinating conversation with a man who worked at a Shipyard from WW2 until the 1980’s. Mostly Navy ships.

His only job was designing spings for ships. Springs have to be the correct physical dimensions but also have the correct rates of stetch or compression.

I wish I had recorded him. We talked for 20 minutes just about springs and it was truly fascinating.

The 2 of you could have talked all day about springs and not be boring.
 
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I would recommend using some grease so it doesn't develop oxidation that might freeze it open.
 
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