I had purchased Fowler 52-520-109-0 Dial Indicator with 1″ Travel with +/-0.5% measurement accuracy.
I wanted to measure the alignment of my table saw blade and fence. You can buy tools that do this using the miter slot track with a dial gauge included for about $70. For example, this one:
This had fairly limited travel and I already had a dial gauge. So I designed one. I did the design while I had my morning coffee before work. I cut it while finishing my email so I built this with about 30 minutes of total time. Lockheed provided access to the laser-cutter and also provides the material for hobby use:
I made the part from 1/4 inch think acrylic and manufactured it on a laser cutter (Glowforge). I tapped two M6 holes (5mm hole diameter) in the back so I could get a secure bolt.
In order to cut this, I used the arrange and post processing with a 0.1778mm kerf:
Fusion 360 renders this in a full joint analysis.