Corrosion Resitant Springs

S

Snickersnee

Joined
May 2, 1999
Messages
1,206
What's the best way to make a spring corrosion resistant?

If there are no stainless alloys that are sutiable, I would reckon some sort of coating would be in order...
 
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Hey Snick.
I noticed you only got one answer on your inquiry about the stainless sprngs.
That is only one mans opinion.I think I would do my homework with the materials in question.
If things aren't tempered correctly they can all be brittle and snap.

The other thing you could do is offer an option perhaps?
I know it would be a little more of a hassle,but I think you are gonna offer a kick arse guarantee when you get started.It won't take long to figure out which is the best spring material.

You could also build about three of them for yourself and see what happens.This is in your field of expertise and you know best what you want and how it should work.

The last and to maybe answer this inquiry... I know that some of the new coatings like Titanium Nitride and the like are very tough and wear very well. I used drills and taps coated with some of these different materials to cut some very hard to machine materials.
Some of them weren't necessarily hard,but very abrasive like glass filled teflon.That stuff ate up regular HSS tools like you wouldn't believe. I don't know about the flexibiity of these materials though.
A simple phone call to a local shop tht does the coatings would answer that.
I recall a black coating that had just came out when I got hurt that might be suitable for what you want.
I don't recall what it was though.
HTH.

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>>>>---¥vsa---->®
The civilized man sleeps behind locked doors in the city while the naked savage sleeps (with a knife) in a open hut in the jungle.
 
Why don't you try good old 440C hardened to a spring temper (Rc 45-48) Experience has shown that it works well in lock back folders. I have had customers who also use 316 SS for very heavy leaf springs.

For increased stain resistance polish it to a full mirror.

The TiN coatings are also a good idea as long as they are applied over a very smooth substrate. A pitted substrate could lead to pinholes in the coating. Tight inside corners should also be avoided because of the Faraday effect during application which tins the coating severely on inside corners.

Note TiN coatings are applied at about 750F
the temperature may affect the temper of the substrate.

The best person to talk to about spring tempering is your local heat treater. A knowledgeable individual will be able to recommend a good material and heat treatment proceedure.

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george
www.tichbourneknives.com
sales@tichbourneknives.com

 
The springs themselves will be an eighth of an inch thick, and half and inch at their widest, and will be functionaly 3-4 inches long I reckon.

They will be requires to flex one quarter of an inch maximum.

I'm gearing up to start making navajas and I'm experimenting with variations on the clasp lock and incorporating modern materials.

I've done some prototypes in mild steel, just to see how my designs are working mechanicaly, and preparing to do some real ones for destructive testing purposes.

440C I'll have to try, but how do you use 316 in a spring? It's austentitic, so you can't temper it, do they work harden it instead or does it get its spring by shear thickness?

From what I know of 316 as a structural material, it seems it would work harden to the point where it'd find a shape it likes and stay there. I remember some meat hooks in a cow factory that did that, they bent under weight to a certain point, but then would go no further.
 
316 is used in applications where the amount of distortion is very small relative to the thickness or permanent distortion will take place.

If I were in your place I would use the 440C spring tempered. This should give you about 30 degrees of arc without fatigue or failure. I am getting 60 plus degrees on 1/16" X 1/2" fillet blades without any problems, some have been flexed by customers to 90 degrees with out failure. This is at RC58 not the softer spring temper.

If you decide to use the harder tempers be aware that the amount of force required to flex it will increase. You may be able to use that feature in fine tuning the spring tension. If you want the spring a little stiffer go a little harder on the temper.

Good luck

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george
www.tichbourneknives.com
sales@tichbourneknives.com

 
Thanks for the info, I'm going to get some steel sometime next week.

The navaja incorporates a lever-like opening mechanism, so stiff springs are less a problem as you've got some small mechanical advantage going for you.
 
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