Folder question

[Roughcountry]

I just finished one of the folder kit's. Had fun doing it and learned alot in the process.

My question is, why do most of the lockbacks have two spring pieces instead of one for the lock bar? I want to build a few from scratch and wondered why shape two springs instead of one.

Any folder experts? Thanks

[Lin Rhea]

Roughcountry,
              There are several types of lockbacks, but may I assume your talking about the type found on Buck's 110 folder? If so, the top piece is actually a locking bar and not specifically a spring. The spring is actually captured inside the two rear bolsters and applies pressure upward onto the locking bar. Notice that there is usually one pin in the locking bar so it can pivot. If I'm off base on the type of lock back, just disregard. Lin

[Roughcountry]

Thanks for the reply Lin.
The type you describe is what this kit had. It had a pin and lanyard tube on the rear of the liners to hold both springs side by side..
There were two identical springs putting upward pressure on the lock. They were pinned side by side and together were the same thickness as the lock. I noticed most of the kits from the supplyer were the same. Just wondered if a single spring was to thick to temper or possible to stiff.

[Lin Rhea]

RC,
    I see what mean. I think maybe your right in that ONE thick spring (in comparison to it's length) would be over stressed due to the amount of travel. Dividing it into two thinner, thus weaker, springs, might be their answer.
     This is where engineering plays a big part in the design. Very interesting. Lin

[Roughcountry]

Thanks Lin. When you put it that way it makes sense. I think Brownells has some spring steel that thickness. I noticed a tip on heat treating springs in thier catalog that I'll give a try. It's from a gunsmith with over 3000 springs out there and only knows of three failing.

I would post a picture of my folder kit but can't get it on photobucket. My ISP goes down before I can lode the picture.
Thanks again for the help. RS

[IB]

[OconeeDan]

Roughcountry, what is that tip on making springs?

[Roughcountry]

Thanks Vance, you got this confuser stuff figgered out.

Dan, It was a life long trade secret of Master gunsmith John Frazier.
Number one is all lines must be true and tapers are similar to a buggy whip. Beyond the end of the taper, leave part of the steel attached. hold the spring by this while hardening to prevent heat bled off.

In a dark or unlighted corner of your shop, heat the spring untill it just shows red color and and quench. Now grind to exact shape and dimentions. ( I asume that means grind off the extra holding spot)
Next take a quart can and pound a indentation in one side deep enough to hold the spring.
place the spring in the indent and cover it with moter oil. Set the oil on fire and let it completly burn up. Then throw a handfull of dry lime over it and let sit for a couple of hours.

The spring is now properly tempered.

I left a few words out cause of one finger typing but thats the meat of it. RS

[OconeeDan]

Wow, not what I expected.  Interesting.  Thanks for your time, Dan

[Lin Rhea]

Well, I learned something. Lin

[Roughcountry]

Brownells has two types of steel for flat springs, 1095 and 1075. They also have a chart for drawing these steels. I've noticed some of the kit folders have O1 toolsteel springs and others just don't say.

I've not found in print what stainless is used for springs. I watched a guy make round compresion springs at the Keyport navel station long ago. What ever steel he used air hardened.

[SoNevada Archer]

Well I'm no expert by any means but I have used 1084 & 5160 in high carbon steel as well as 440C & AEB-L in stainless. I have only made a couple lock backs. I drifted more to the liner locks. But I have heated the non-stainless spring steel with a torch to just red, quenched in cool olive oil then one temper cycle at 350*F for one hour with good results.

[Roughcountry]

Good info S Nv Archer, Thanks.