I
don’t often use the standard plastic pins for attaching trucks, because
they don’t always work well with the 3d printed models. I use Walthers
Brass Machine Screws (947-1072) #2-56 x 3/16 flat head. You may have to
clip the screws or drill deeper for some models; the nature of some of
the hoppers limited the depth possible for the holes without poking
through. And if the hole gets too big just fill it with a little white
or wood glue and put a screw in while still wet.
