spring install ? in auto

[SVanderkolff]

I am once again attempting to make my first automatic. I have install the torsion spring in the blade and liner of the knife but the spring does not seem to give it enough torque. I tried putting more tension on the spring but it simply deformed. I am using a 3/8 od spring from knifekits. the blade is 4" long 3/16" thick. It is still heavy as I haven't yet ground the blade. Should I be using a heavier spring or is there some trick to installing the spring that I am missing.
Thanks
Steve

 

[McAhron]

I bet once you grind the blade you'll be OK as removing half the weight will mean the spring has a lot less of a load to propel it.Also you didn't state which model of spring,High,Maxx,Mega,etc.There is a big difference in the power between the lightest(High) and heaviest(mega).

 

[Fellhoelter]

They seem to require about a quarter turn of pre-load.

Deformation usually means the boss in the middle of the cutout is too small.

It can also mean it's too big, as I discovered when I tried to use the knifekits annular cutter on my 1st auto.
The spring tightened up on the boss and wrecked a bunch of springs before I discovered the problem.

Make sure there is enough depth in the cutout for the length the spring grows while under contraction too...

I have a formula here somewhere to calculate diameters and depths if you end up needing it.