finish plate

finish plate

[′fin·ish ‚plāt]
(design engineering)
A plate which covers and protects the cylinder setscrews; it is fastened to the underplate and forms part of the armored front for a mortise lock.

armored front

In builders” hardware, a lock front which consists of two plates: the under plate (an unfinished plate fastened to the case) and the finish plate (a plate which covers the cylinder setscrews, thus protecting them from tampering, and which is fastened to the under plate); used on mortise locks.