That’s a 0.035 inch = 35 mil hex wrench, of which Eks reminds me “Any time your design requires a tiny [obscene gerund] wrench, you’re doing it wrong”.
The sequence goes like this:
- Loosen that tiny setscrew
- Unscrew & remove the mirror boom
- Remove brass screw & azimuth pivot
- Tighten screw in elevation pivot
- Tighten tiny setscrew on elevation arc
- Reinstall & tighten azimuth pivot
- Reinstall mirror boom
- Tighten tiny setscrew
Going strong after seven years!