For me, setting the proper amount of tension depends on the size of the knife, blade and the thickness and shape of the spring. I have a piece of precision ground steel that I put holes in at the proper spacing to allow me to get a feel for how much resistance the spring is going to have. When I find the spacing that seems right, I transfer that hole pattern to my liners. (Stack your liners and drill them at the same time.) Also remember as you grind away any spring material, especially between the center pin and the pivot pin, you will change the characteristics of the spring tension.
You said yours was a kit so I am guessing it came with liners and a spring that was already hardened and tempered. I suspect that these would be preset by the creator of the kit.
As far as compressing the spring for assembly, I have had good luck with using a vice.
I put the rear pin in and the center pin through the spring and have my liners on both sides of the spring.
Then I take a thin piece of micarta or G10 (About 1/2 inch wide by 2 inches long.) and place it between the liners with one end against the spring about half way between the center pin and the pivot pin hole.
I open the jaws of the vice and place a piece of leather on one side. With the knife on its side (parallel to the floor) I put the back of the knife against the leather and close the vice to put tension on the peice of micarta.
As I gently close the vice, the micarta piece will push against the back of the spring and allow me to put the blade tang into position. I then put my pivot pin in and release tension from the vice.
This is probably as clear as mud but hopefully it will help.
Johnny Roberts
