Decided to make my own version of the M18 battery adapter. This is a bit more involved than some of the others on here. Its two pieces which can be printed without supports. It uses 5 M3 flat head screws and nuts to hold together. The two halves will clamp the wires and spades in place. I used the crimp style "blue" sized spades. I removed the blue plastic sleeve and solder the wires in place. These spades come from many different places so your millage may vary with fit. Has three holes on the bottom for #8 sized wood screws or M5 bolts to hold to attached it to something. Photo shows an earlier version but the STLs have the updated screw positions.