OK, so today I learned what a ‘tri-wing’ screw is. Had the retainer spring for the door on my toaster oven fail, allowing the door to slam down without any resistance. OK, I can handle this… just take off the screws holding on the sheet metal body and I should be able to get to the door retainer spring… No Problem.
Pulled the screws off the back, flipped the thing over and removed the 4 feet (all standard #1 phillips screws) and WTF… the last 4 screws on the bottom of the thing only had 3 ‘wings’.
Thankfully I had bought a set of screwdriver tips for security screws from Harbor Freight years ago, (and even more thankfully I was able to find them). Sure enough, there was the correct screwdriver tip (#1 tri-wing). Pulled the offending screws, then it was off with the shell, a slight redesign of the connection from the spring to the arm on the door using a small split keyring, re-bent the end on the spring (it had broken off) and voila good as new.
Oh, and I put the set of security screw bits back in the shop in the spot they belong… for next time!