Post by Big AlMy trailer is put together with a million screws with what appear to be Torx
head screws. Except, a T15 is too small and a T20 is too big. What are they?
Your bit is probably in the common 100 pc security bit set, as sold on
Harbor Freight or eBay:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91310
eBay item 290000348015
It's got all kinds of oddball bits, and even if you don't find an exact
match, you'll find something to turn your screw. The case is very
flimsy and mine broke at the "hinge" before I was able to get it out of
the package (much less flimsy, the kind of plastic that commonly
packages small electronic stuff -- difficult and dangerous to open).
Else, if your screws really are Torx-shaped but sized between T15 and
T20, grind down a T20 a little.