If you're making your own pedal box this is the balance bar to choose. Industry standard 7/16" UNF threaded, hardened bar with 5/16" UNF anodised clevises.
Phosphor bronze spherical bearing. Complete with reamed bearing tube (31.9mm o/d, 26.2mm i/d, 35mm long) to weld into your own pedal.
We know these aren't the cheapest around but they are by far the nicest we've seen.
BALANCE BAR ASSEMBLY #BBAR