Other than the wheels and handles, I use 1/4-20 threaded knobs and inserts, a couple of washers and lock[-bolts.. I drill the holes to the front and rear edge -- 1/2 way from the large holes in the rocker box sides and angle them of course. It's a pretty straight forward process. If you need more info and would like to ask questions do feel free to email or call directly (650-315-6578). Dennis
I use 3/8-16 T- nuts glued on the inside.
My Obsession and Starsplitters all use 3/8-16 steel knurled grip knobs instead of T- nuts. I believe these are what they use:
Note: these are knobs but they're not used as knobs, they are inset into the rocker box.
What's nice about them is the hub is 3/4" in diameter so the nuts on the mounting bolts are riding against steel, no washers or metal against wood.
The through hole is 3/4" and there a 1.5" counter bore on the backside where the head fits.
The downside is they are 1 inch in length so the sides of the rocker boxes need to be double thickness, my 13.1 inch Starsplitter rocker box sides are ~ 1.4" thick.