This screw and locking washer is commonly used on Stern machines to fasten various items to the playfield.
Comes with locking washer.
Often used with the #6 M/S flat washer (sold separately).
Williams / Bally reference numbers 4006-01005-06, 4006-01003-06, & 4006-01005-06.
Data East / Sega / Stern #232-5201-00