LB7 - pin location question

[BigAl62]

I may have posted this pic a couple of years ago and I think maybe I asked the question at the time but I’m old now so my memory is apparently fading. This is my stable of LB7’s. The lock bar pivot pin on the second from the bottom is shifted toward the middle. I’ve seen a few other pics on here with that pin location. Does anyone know the why, when, where, how, of the location difference?

[227UH]

Well by looking through the Schrade Cutlery catalogs, 1995 shows the pivot pin closer to the blade. You will have to zoom in to see it.

1996 shows the pin moved further away from the blade.

It seems they wanted to try a new design that releases the lock quicker.
Where should the fulcrum be placed?
To lift heavy loads with minimal force (First-Class Levers): Place the fulcrum as close to the load as possible. This maximizes the effort arm, providing the highest mechanical advantage so the load is easier to lift (e.g., a crowbar).
For speed and range of motion (First-Class Levers): Place the fulcrum closer to the effort. This sacrifices mechanical advantage but allows the load to move a greater distance at a faster speed.

[OLDE CUTLER]

In the process of repairing and customizing the LB7, LB8, and 6OT I run into this as shown by the 2 lock bars below.

[227UH]

I just found something interesting.
The Buck 110 folder was introduced in 1964.
The Schrade LB7 was introduced in 1977, an almost exact copy.
Check out the rocker pin location of the first Buck 110 model, right in the center of the lock bar.
After some trial and error, they moved the rocker pin closer to the blade.

[BigAl62]

Very interesting. Thinking thru the fulcrum point, it would seem that the further away the fulcrum is from the lock, the less distance you would have to press the release. And unless the spring tension was changed, the less force would have to be applied. Conversely, the opposite would be true if the fulcrum was closer to the lock. Or maybe the lock bar doesn’t engage the tang quite as much on the newer ones? Buck seems to have moved the opposite direction.

[JAMESC41001]

I’ve taken a couple lb 7’s apart. There is a spring inside to make the rocker arm spring back after pressing down to release the lock and close the blade. Schrade used a spring made from round stock and one the was flat. I believe the change was to add strength as the knife I was working had a broken spring. The pivot point may have been changed as an attempt to solve a problem of broken springs. I have some picks somewhere. I will post when I find them.
Jay

[OLDE CUTLER]

I’ve taken a couple lb 7’s apart. There is a spring inside to make the rocker arm spring back after pressing down to release the lock and close the blade. Schrade used a spring made from round stock and one the was flat. I believe the change was to add strength as the knife I was working had a broken spring. The pivot point may have been changed as an attempt to solve a problem of broken springs. I have some picks somewhere. I will post when I find them.
Jay

Yes, spring breakage was an issue with those. I have repaired several.
https://www.allaboutpocketknives.com/kn ... len+wrench