Astrophotography Mount for Sigma 150-600mm DG Contemporary - V2

This is an updated version of my original bracket for mounting the popular SIGMA DG HSM 150-600mm F/5-6.3 telephoto zoom lens into equatorial-style astrophotography tracking mounts.

The main updates are better tolerances, especially for the roller-bearing track that the back of the lens sits within, and also the type of screws used to hold the lower "base" and upper portions together. I decided to upgrade the design to use metric M4 screws housed within custom thumb knobs for ease of assembly/disassembly, especially when using the lens for on-the-go astrophotography sessions or in the cold when wearing gloves.

I STRONGLY recommend printing this part with an engineering grade plastic material, such as ABS, ASA, polycarbonate or Nylon 6, 12. I would avoid using PLA entirely. For such a functional part that holds a very expensive piece of equipment, the durability, rigidness, and heat-resistance that these higher-end materials offer is crucial to the reliability and accuracy of this part.

The hardware can be purchased in the U.S. from the following supplier -->

Threaded inserts

4X - https://www.mcmaster.com/catalog/131/3643/94459A796

10X - https://www.mcmaster.com/catalog/131/3643/97171A120

4X - https://www.mcmaster.com/catalog/131/3787/93365A160 OR https://www.mcmaster.com/97171a230/

Screws

10X - https://www.mcmaster.com/92196a108/

4X - https://www.mcmaster.com/91287a710/

1X - https://www.mcmaster.com/96006a702/

3X - https://www.mcmaster.com/catalog/131/3572/96006A703

For the screws, I recommend using all stainless-steel grade, as depending on your specific use-case like if you have this lens as part of an observatory or under a tarp like myself, the SS will offer much better corrosion resistance that other grades such as zinc-plated or black oxide coated.

For strength when printing, I recommend a minimum of 3 wall perimeters, with at-least 30-50% infill.