Center Pin Questions

[rmfnla]

I've been thinking about knife design, especially the way handles are attached.

We are all familiar with the 2 pins per handle + the backspring pivot pin that goes through the entire knife. I am wondering if that pivot pin really needs to go through the handles. I have noticed that if a handle is cracked it seems to be at the pivot pin more often than not, especially in knives where the handle material is thin in that area.

The pivot pin gets stressed during blade opening & closing so it is conceivable that it moves a bit, which could cause the handle cracks. It would sem to me that peening the pin at the liners and drilling a relief area in each handle to accomodate the "head" would result in a stronger overall design.

Any thought on this?

[ea42]

The only way I could see that working is if you plan on glueing the handle material on, otherwise you'd have no way of pinning that area (or anyplace on the bottom of the handle) once the springs are in place.

Eric

[Knife Nut]

Interesting question you've posted. I don't see any more scale cracks at the backspring pin then I find at the pins closer to the bolsters. Due to the physics of the backspring flexure, that pivot pin should not move to cause stress on the handles at that fulcrum point. I'm interested to hear other's give their on this topic.

Paul

[rmfnla]

I have three Queen slimline trappers and all three are cracked in that area (and a few other examples as well). The handle material is a bit thin there but even so...

As to ea42's reply, how about this:

1. Peen the handle pins into place in the liners.

2. Assemble blade(s), backspring(s) and liners with pivot pin; peen pivot pin down to liners.

3. Insert steel spacer block between liners to support handle pins.

4. Place each handle into place, peen & finish handle pins.

[Another Knife Collector]

Occaisionally I've run accross vintage pearl handled knives that have center pins hidden under the handles, I don't have one anymore, but I bet there's someone on here that has an example.