I'm building a 10 inch F3 DOB scope. I decided to try a 3D printed mirror Cell. If it fails to hold collimation for what ever reason I can replace it with something better. It is printed in PETG and is 1/2 inch thick with a hollow grid structure inside as is usual with 3D printed parts. It has about $20 in stainless Steel hardware some used to hold it together. It was too big to print as one piece on my printer. Took about 8 hrs to print all parts. However there was an incremental design process so parts where printed many times through each iteration.
The 3 collimation bolts (springs not shown) move the whole thing so the lateral mirror supports move with collimation and always touch the mirror in the same spot at the center of Gravity of the 10 inch 1.1 thick mirror. The top radial arm hold the collimation bolt. A separate finger at the top of the mirror box will keep the mirror from falling forward.