Dan,My boxes are ABS with non magnetic brass inserts and screws. The box size is a little over 4.5 in wide from the front 2.5 in tall and 6 in long.
Dan,
Can you share the part number and source for your ABS boxes?
So it sounds like they are not standard 6mm shafts. Where did you find knobs that worked? I'm reluctant to file down the shafts.
email back from dave; says the data sheet shows shaft = 6.35mm, which is same as 1/4"