(Note: Measurements are outside max. dimensions unless stated otherwise).18th Century : Plain insert thread escutcheon.OUTSIDEHeight 22mm. (7/8")Width top 10.5mm. (3/8")Width base 10mm. (3/8")Depth 3.5mm. (1/8")Thickness (variable) 2mm. (1/16")KEYHOLEHeight 18.5mm. (11/16")Diam. of hole 7mm. (1/4")Width at narrowest part of neck 4.5mm. (3/16")Width at base of taper 6mm. (1/4")Usually glued in or could be pinned from inside flange.There are escutcheon pin fixing holes inside top and bottom of flanged insert.