Wow that's a great close-up.... I'll tweak all of the little stuff down the road, but I wonder why they left that off?
I want to almost guarantee that the front tumbler tops are found parts. I recognize the style of assembly, just can't think from where.... If I remember correctly, you could reach down and lift the 12-slotted ring on the top of the tumbler, then rotate the tumbler (or whatever is originally underneath that piece) to another position. The tumbler section would have a pin sticking out of the top that could seat into one of the holes in that top ring, so you could pull up on the top, turn the tumbler to one of 12 positions, and then let it drop back down to lock the position in. Those two thin metal strap pieces under the knurled top knobs work as 'springs' to hold the top down against the tumbler keeping it locked in place. I probably described this poorly, but I know I've seen something like this before.
opcorn
