Back springs.

[Matches]

A few years back, I began to wonder why the blades on a new Uncle Henry stockman I bought opened so easily and the Old Timers were considerable more difficult and varied in difficulty. I posted the question here to the Schrade rep. (Tim? Tom?) and his response was only that they were all manufactured the same way and with the same spring material.
Reading another post here now (regarding display cases), it was mentioned that springs may be adversly effected if the knives were displayed opened half way. This has rekindled my curiosity about back springs. Does anyone have any concrete information about why some new Old Timers might open easier than others and do the springs lose their "springiness" over time? Thanks for any input

 

[Codger_64]

Hopefully you will soon get a more educated opinion than mine, but I think, spring heat treatment and material being equal, it boils down to tolerences. How close were they manufactured to specifications? Were the tangs and/or springs over or under polished, opening the tolerence gap? A spring's tension rate is dependant on it's compression/flexing. It gets stiffer the further it is pushed from it's relaxed state. Closer to it's relaxed state, it exerts hardly any counterforce. I think the later assembled knives in particular had less careful assembly and quality control.

On storing the knives with the springs compressed, I think it is like the old style leaf springs in cars and trucks. A constant load over time will take out some of the arch, and the ability to resist flex. You get a '63 Buick taildragger. That is my thinking. I have a UH lockback that has a weak spring. I have a UH slipjoint that has an overly powerful spring.

Codger

 

[Matches]

Thanks for the reply Codger_64...sounds educated enough for me I enjoy my Schrades and believe they are terrific for the price. I just get to wondering why all my Case knives seem to have the same tension and the Schrades vary. I'll assume that's one reason the Case knives cost more.