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Spring re-arching

Posted: Fri Mar 24, 2017 10:16 pm
by ken98k
Is spring bending, or re-arching something that is commonly done to correct weak snap in pocket knives?

Re: Spring re-arching

Posted: Fri Mar 24, 2017 11:29 pm
by just bob
This is from the Adrian Harris book copyright 1981.

Re: Spring re-arching

Posted: Fri Mar 24, 2017 11:33 pm
by muskrat man
krinking or kinking springs can be done to improve weak snap, sometimes it works sometimes it doesn't. depends on the hardness of the spring and how much wear is on the spring and tang.

I have to disagree with the illustration in Mr. Harris' book. Striking the spring where he shows will shorten the distance between the butt and center pin holes causing a misalignment in the holes on reassembly. Strike the spring just forward of the center pin for best results. JMO, YMMV

Re: Spring re-arching

Posted: Sat Mar 25, 2017 3:27 am
by ea42
Totally agree with Kaleb, you'll never get the pins back in, and if you do you'll likely crack the covers and pull a burr off the pin in the process.

Re: Spring re-arching

Posted: Sat Mar 25, 2017 10:41 am
by orvet
Absolutely correct! ::nod::
I use a block of micarta with a hole in it and a dead blow hammer to to bend the spring in front of the rocker pin hole. It is quick and easy and no damage to the spring from the hammer or the stiddy.

Re: Spring re-arching

Posted: Tue Apr 11, 2017 8:05 pm
by danno50
orvet wrote:Absolutely correct! ::nod::
I use a block of micarta with a hole in it and a dead blow hammer to to bend the spring in front of the rocker pin hole. It is quick and easy and no damage to the spring from the hammer or the stiddy.
Dale, can you please explain what a dead blow hammer is. How hard do you hit the spring?
Thanks
Dan

Re: Spring re-arching

Posted: Sat Apr 15, 2017 5:29 am
by orvet
A dead blow hammer usually has a plastic cover and is filled inside was sand or lead BBs.
The idea is to keep the hammer from bouncing off of what ever is struck and losing energy.
If you strike an anvil with a normal steel hammer that hammer will bounce up off of the anvil, if you strike it with the dead blow hammer it will go "thud" and just stay right on the anvil.
Since the dead blow hammer doesn't bounce more energy is transferred into the item you're striking, so you don't have to hit it as hard as you do with the steel hammer. Just how hard you hit it is something you have to learn my practice and experimentation.


Here are a couple dead blow hammers.
The Craftsman is a replacement for a hammer I purchased about 1979. I think the price when I replaced it a few years ago was about 35 or $40.
The orange colored Pittsburgh hammer is a harbor freight brand. I think I picked it up on sale for about 7 or $8.
Deadblow Hammers.jpg

Re: Spring re-arching

Posted: Sat Apr 15, 2017 5:35 pm
by danno50
Thanks Dale. I just ended up giving the spring a couple of raps with a small tack hammer. Checked the deflection of the spring after each hit. Got enough re-arch acceptable snap came back to the blade, not bear trap snap, but I didn't want to push my luck hitting the spring too many times.
Dan