Pivot pins and stop pins

[straitshot]

Both slip joint and locking folders find their way into my pocket, but I'm always wondering about the pivot integrity. I've only had one fail yet it was enough to plant that little doubt when considering a new one.
I'm unsure of such things as:
1) do brass bolsters mean brass pivot pin, and stainless or NS mean stainess pin? I once read one mfg. used hardened pins instead of wire but don't remember which one. Wouldn't a brass pivot be less durable? On one thread I saw a Buck in NS with a brass pivot pin. I bought NS because, for one reason, I wanted a stainless pin. But is it a NS pin?
2) Stop pins are always suspect to me. Some blades have a radiused base that bears against the stop pin (liner lock usually) and would appear to have a propensity for overriding the stop. Chris Reeve knives illustrate how they design a positive stop pin notch in the blade base- very well done.
3) I have usually gravitated to threaded pivots with large "heads" but then I got one that was cross -threaded... not very comforting in what is considered a midrange quality knife.
4) Some pivot pins and stop pins just appear too small. The spine whack test doesn't answer it for me and I've never seen a test on how much force is necessary to cause a folder to "over-open".

The one that failed (a popular knife) was due to a radiused blade base ground too much so that it wedged the stop pin enough to open "too far". This is one reason I now prefer a slip joint or lockback, yet liner locks usually have less steel cut away from the blade base than lock backs.

Am I just being too picky?

 

[STR]

The pivot and bolster are separate items.

NS is usually referring to Nickel Silver.

Even a 1/8" diameter pivot barrel is quite strong. It takes a great deal of force to shear a barrel that size or the #2 screws that are used in it. In all likelihood the barrel that size is still stronger than the lock or the body of the folder unless it is steel lined. Again it isn't written in stone but in most cases.

Like anything mass produced as these barrels and pins are there are on occasion one or two that don't get threaded correctly or are out of tolerance one of several other ways.

Solid pins are going to be stronger usually than a barrel but both are certainly stronger or at least equal to all other parts of the system to make it work in a folder.

STR

 

[plowboy]

straightshot, I've wondered about this too. I had reached the conclusion that they are relatively strong since there isn't too much discussion of pivot pins or stop pins failing. Now locks....it seems everyone wants to discuss lock failures.

One of the bits of data that helped me put this issue to rest is lock strenght tests that are done on some brands. For example, Spyderco, Cold Steel and others do tests often. I also read a post by Chris Reeve himself (at least I'm 99.9% sure I'm remembering correctly that it was Mr. Reeve) that stated that Spyderco had tested lock strength on the Sebenza for him. The test revealed that the Sebenza took approximately 400 pounds before the lock failed. It's my understanding that some Spydercos (and SOGs) take considerably more pressure to generate lock failure. If my thinking is correct, the pivot pin is also bearing this pressure. If this is so, and STR can probably provide more detail on this, then the pins are strong enough to handle anything we do with our hand and arm strength.

STR, is my thinking correct in the previous paragraph?

Great question for discussion, straightshooter.