Can be titanium (gr.5) used as spring for back lock folding knife?

H

Honzis

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Jan 12, 2018
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Hey simple question, can be a titanium of appropriate quality used as a spring for back lock on folders?
 
My usual caveats: I defer to someone more knowledgeable. I barely know what I'm talking about.

My guess:

The yield strength would dictate how well it works in surviving as a spring. Ti has a great strength here, and would be valid for this purpose.

Titanium has a much lower wear resistance than hardened steel. If the rocker and pocket are hardened steel, it would be far harder than the Ti and wear it away over time. This takes into consideration grit (sand, etc) getting inside and acting as an abrasive.
I doubt it would be noticeable for a long time, but it would probably first get "sticky" as the Ti galls, then the spring exert less force as it wears away.

Since the spring force isn't likely to ever increase beyond where you set it, and it would probably be far lower than the maximum strength, it shouldn't matter which you choose (steel/Ti)

So the degradation over time would be the reason I would view it as an inferior choice.
 
I'm curious to hear what people have to say about this. I have been working on a lockback design. I bought the (steel) springs from Jantz. I don't see why titanium wouldn't work, you would just need to work out the material thickness/dimensions/bend to get the right spring pressure. I was kicking around the idea of making an integrated back spacer/spring out of titanium.
 
I guess that one would want to carbidize the section of titanium that comes into contact with the steel blade tang (or lockbar! Oop) to avoid galling. Can't say I've seen it done in a back lock, but that doesn't mean it hasn't been done!
 
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For just a spring, with a steel back lock bar, absolutely would work and work well. For a one piece backspacer and lock bar You could, but I’d suggest carbidizing the end as suggested above.
 
Steel facing the titanium where it would contact the blade tang would solve the wear problem. This is what many higher end frame locks do. Have you looked at the Lion Steel Thrill? It's a slip joint with an integral handle and back Spring machined from aluminum. The end of the spring arm has a steel face. If you're u had Ti liners and Ti spring you would probably need a clearance gap to prevent galling.
 
Late to this thread, but yes. I make All-Ti knives and the folders i make are all back locks. The spring, hammer (lockbar), spacer and screws are 6AL4V with another Ti alloy as blade which can be heat treated.
 
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