NZ Duty Code 8467.22.0029F
2020 slot has depth of 6mm
Single 2020 corner brackets have M5.5 hole?, thickness 3mm, so need M5*8 + washer, so M5*8 & M5*10
For Hammer head bolts: M5*3+nut =
Dual 2040 corner brackets have M4.5 hole?, thickness 4.5mm, so need M4*10 + washer, so M4*10 & M4*12