Because it will be easier to see some features in the CAD model here is the modular system. It is made of 4 parts:
1) sled which fits in a 29 mm body tube (not coupler tube).
2) Outer casing that can be put on sled directly to protect and strengthen sled for shock cord attachment. Simply using the middle screw only gave a system that only broke under 72 lbs force...adding the other two screw holes should increase that markedly.
3) Bulkhead for 38 mm Nose cone mounting. This fits Wildman available injection molded composite cones and Madcow available RW filament wound fiberglass cones with one wrap of masking tape (the IDs are really close, but not the same).
4) Drill guide so the holes in a nose cone shoulder/coupler line up with the holes in the bulkhead. This fits both NC types as their IDs are very close.
I will be offering a limited number of these for sale as a test of the manufacturing and shipping process as a way of making an informed decision about going forward with becoming a niche vendor. I have been contacted by several folks so far and have 3 units committed, so if you have interest please let me know via PM. I will be invoicing through PayPal, so you will have PayPal protections, and I won't invoice anyone until I have the desired unit ready to ship. I would expect to be ready to ship units next week as I have all screws and shipping supplies in hand.
The kit will come with appropriate screws for NC and outer case mounting (along with a few extras too). The buyer will provide eye bolt and associated hardware (nut capture is 11 mm), and mounting screws for EggFinder mini. I have to get final print times before I can firmly set pricing, but I plan to offer three versions:
1) NC mounting kit: Sled, Bulkhead and Drill Guide...~$20
2) Shock Cord mounting kit: Sled and Outer case...~$20
3) The Works: Sled, Outer case, Bulkhead and Drill Guide...~$30
Shipping will be standard USPS for a flat rate of $4 (CONUS) for up to 4 units.
I want to thank the folks that have beta tested the earlier version, and provided really helpful suggestions. I'm very sorry for the eyebolt failure with Salvage-1's unit...I was so focused on the printed part that I didn't give appropriate thought to the hardware.
I'll post up some real pictures tomorrow evening along with updated breaking strength info. I've used almost a Kg of filament designing, test fitting, breaking, and redesigning these so I think I have reached a sound design. Also of note, these are printed at 100% infill, so there is no void space within the printed parts. As a test one of these sleds has also been sitting in my car for the last 2 weeks spending parts of each day (up to 97 deg) in the direct sun with no sign of deformation or warping...I love PETG.
Comments are welcome as I've tried to do this as transparently as possible.