Heat, salt water and magnets: choosing the right material for a spring or washer
A spring that is correctly sized and wrongly specified will still fail. Heat relaxes it, corrosion pits it, and the wrong alloy near a sensor puts a magnetic field where nobody wanted one. Here is how the material choice actually gets made, in the order the questions come up.
Disc spring stacks: how series and parallel stacking changes the force you get
A disc spring is a cone shaped washer that carries load along its axis. On its own it does something no coil spring can: it delivers a very high force in a very short installation length. Understanding how disc springs work in stacks is what turns that into a design tool, because the same part can be arranged to give you travel, load, or a curve that changes as it compresses.
Type S or type VS: how to pick the right safety washer, and fit it properly
Most of the questions we take in Ann Arbor are some version of the same one: which washer, and does it go in the right way round. Both are worth answering properly, because the wrong choice or a careless fit undoes the locking effect you paid for.
Why bolted joints come loose under vibration, and what actually holds them
Every maintenance engineer has seen the same failure. A joint that was torqued correctly at build comes back six months later with the nut finger tight, the paint cracked around the washer face, and the bolt head polished where it has been moving. Nothing is broken. The joint simply stopped clamping.