Spectronic-20 Sample Chamber Lid

thingiverse

The Spectronic 20 is a legendary single-beam spectrophotometer that was originally manufactured by Bauch & Lomb, a renowned company in the field of analytical instrumentation. With a staggering production run of 58 years, an estimated 600,000 units of these iconic devices were produced. The reason for its enduring popularity lies in its simplicity, durability, reproducibility, and ease of use. All fundamental components that can fail are easily replaceable off-the-shelf parts, making repairs straightforward, especially in the older fully analog versions. The source is a standard GE 1630 bulb, the monochromator is a diffusion mesh, and the detector is a simple phototube. The display is simply a calibrated analog voltmeter. In newer electronic versions, the detector is replaced with an off-the-shelf photovoltaic cell and the display is a very simple board using standard electronic components and ICs. Both devices are easily repairable by anyone with basic electronics knowledge, a multimeter, and a soldering iron. This design aims to replace the only component that actually breaks - the sample chamber lid. While you can use the broken lid or set a painted styrofoam cup over the chamber to block light out, these solutions don't always work well. You'll eventually lose the lid or paint will flake down into the chamber and mess up your measurements. My solution was to design a cover for the original sample chamber that is fully 3D printable and can screw into or be glued onto the case or body of the device. For more information on the Spec-20, see the relevant Wikipedia article. The design for the hinge is shamelessly ripped off from NCHippy's Large Hinge, which is a testament to its effectiveness.