One of the biggest challenges in this turntable build was attempting to recreate the headshell connector. This part allows for quick and easy interchangeability of needle cartridges between turntables. Otherwise, I would have to unscrew and disconnect the cartridge cables every time I wanted to remove it. Wanting this turntable to be compatible with my other ones, which accept standard headshells, I figured I had no choice but to make this connector.
The challenge here was the amount of small and complex parts needing to be made; a threaded locking mechanism, a slotted body, and insulated piece to house four spring-loaded brass contact pins, and the pins themselves. Then on top of this, figuring out how it will connect to the tonearm and wiring it.
My version did a fair job replicating it, but it took a lot of hard work, several failed attempts and a few design flaws. Part of the reason for my shortcomings was the fact that I didn't want to disassemble my Technics to see how it worked. I just did the best I could from the measurements I could get on the outside.
Here's a diagram of my headshell connector. The biggest difference between mine and the Technics is a snap ring holding on the locknut. This is because my tonearm is a larger, and having to match this larger diameter on the connector, I couldn't slide the locknut on through the back. On the Technics, the locknut is secured by a shoulder on front of the connector body.