I decided to tackle the spoilerboard next. I debated several options and decided to try something call slotwall. I bought a 4x8 sheet of slotwall and some sheets of 1/4" and 1/8" MDF to use as the real spoilerboard.
I've found that the MDF is extremely flat and I'd prefer to ruin small little pieces rather then the slotwall.
This is what the profile of the slotwall looks like:
All of my woodworking jigs use 1/4"-20 hardware, so I decided to use that for my holddowns. I used 3-pronged Propell nuts along with a printed piece to make my T-nuts:
I wound up putting a recess on the bottom and used support:
This was removed quite easily. In hindsight, I probably could have made the T-nut a bit thinner and not needed support.
Here's the propell nut installed:
And how it fits in the slotwall:
Oops. I didn't quite center the slotwall. The left most slot just clears the corner bracket, but the right most slot needed a wee bit of "adjustment", which was done with a file:
The OnShape document can be found here.
The STEP and STL files are here.
Related: Unboxing, Part 1, Part 2, Part 3, Part 4, Part 6, Clamps