(Note: Measurements are outside max. dimensions unless stated otherwise).
18th Century : Plain insert thread escutcheon.
OUTSIDE
Height 22mm. (7/8")
Width top 10mm. (3/8")
Width base 11mm. (3/8")
Depth 4mm. (3/16")
Thickness (variable) 1.5mm. (1/16")
KEYHOLE
Height 19mm. (3/4")
Diam. of hole 7mm. (1/4")
Width at narrowest part of neck 5.5mm. (3/16")
Width at base of taper 7.5mm. (5/16")
Usually glued in or could be pinned from inside flange.