Not a shim as in a washer component. A shim (feeler gauge might be better terminology) is placed in the joint when peening to leave a little slack. Without it on a non-spring knife you would get it so tight you have to push open/closed. GEC uses such heavy springs to minimize the need for leaving slack to alleviate resistance; but for makers that want a lighter spring and a smooth flow they much minimize the resistance of a tightly peened joint. Each knife could leave the factory with a perfect setup, but I am not sure we could afford the extra time to gain it.
Take a blade out of a knife and put it back. You will gain a ton of understanding on the complexities of this process.
After a little thought this evening, I wondered if that might be what you were describing. I usually hear them called a "slacking tool" or "slackener." Basically it functions as a spacer, to establish a pre-determined amount of play in the joint.
I've had "a few" knives apart with the intent of re-assembling them, most recently an "Army & Navy Exchange" 6 blade congress I was repairing for a friend. (More often, lately, I am taking them apart to measure dimensions and study the designs, test hardness, etc.) I do have a vague idea of what's involved. I was pretty sure I hadn't seen a shim in place on the S&M I took apart, but had the thought that if there was
supposed to be one, the absence might explain the problem.
(Just a sidebar, but the different approaches used by consumers and factories are interesting. The cutler uses a spacer to pre-establish a certain amount of play at the
joint; consumers usually look farther out, even at the tip of the knife to see how much play the blade has. Some factories measured the amount of pre-load a spring tip has on the blade, while we consumers tend to look at this as how hard the pull is at the nail nick. It is no wonder we get confused trying to discuss different aspects of cutlery at times!)
Steven, thanks for posting the picture of the Halfrich knife! That is a beauty!
