Have your welder repurpose a vice. You could fabricate any jaws you want. Have plates cut at varying angles. Or build up flat plates to different angles. To accommodate various angles bolt on different angled face plates to your fabricated jaws. Big steel plates with bolt holes welded to standard vise. Then you could pull cleats with your slack snap machine. That are held in place by a modified bench top vice. Weld a nut on the end thread and you could make quick changes with a cordless driver.

You could use four bolts with swivel heads welded to the back of the plates to get the adjustability and rigidity you need.

There are a few comments about welding the bolts to the back of the plates, and I think that's a cool idea. The BlackDiamond guys did the same, so maybe it _is_ a good idea. One idea could be to have some kind of guides on the top (to guide the plates and hold the weight) and bolts on the lower part of the plates, having 3 or 4 bolts per plate to hold it in any position

I would probably go for three different sizes. Even with inserts, the holder will have to be big enough for the largest size, which is awkward for the smallest size. Also, metal on metal will slide. It is not the same as metal on rock. So you need a liner/insert made out of stone for the holder. How about a holder where you slide in the cam from the top, handle first? This would look like a crag with an opening that gets smaller going downwards.

“CAD” Cardboard and Ductape 😂. I can’t believe I haven’t heard that before! Very exciting video ryan! I love hearing your ideation and prototyping process. Have you considered getting a 3D printer for some prototyping and such? It would definitely help figure out the sizing options, mounting positions and other variables for a fraction of the cost! Let me know your thoughts, I’d love to help out with 3D modeling or prototyping if you need! 👍🏻 keep it up

You should probably make the bottom part attached too, and leave a window hole for filming. Otherwise I worry it would torque open.

Maybe something ball and socket style, think the cup on the screw side of a c-clamp, welded onto your plates. Maybe repurpose c-clamps instead of the 3/4 bolts? Would allow for the plates to move but would stop them from falling out.

I’d suggest bugger C channel, use SHS. Much simpler to cut a sight window with a grinder than weld up 2 sides and a spacer at the back. Also, I reckon you’ll still be fighting flex using bolts to position it. Instead, use a timber wedge on each side to space out the rock plates. To neck it down for smaller gear, use flat sections of timber behind the wedges. The timber will only ever be stressed in compression, where it’s super duper strong. You want to avoid (hah) any voids behind your plates as that is where they’ll flex and fail. No way around that with bolts. Retain it all at the bottom with flat bar welded on. Leave the top open and load the places and spacers from there.

you could weld on 4 U shaped groves on the plate that are as deep as a bolthead with the open end of the groves pointing up, so when puting the plate in it 4 bolthedas would slide in those groves and when you tighten them half an inch or less the plate would be held in place by the bottom lip, or alternativly have two long U groves hope that what i said makes sense, too bad youtube dosent allow pictures, but i think you will figure it out(if its still unclear say so i will send sketches on twiter facebook...) best of luck

How about a long hinge like a barn door hinge , with the interior lined with concrete and 2 bolts at the bottom to control the angel ( to simulate a crack in rock ) ?

What if the plates are held captive by a dovetail rail across the inside top?

Are those rock empire cams?