We carry around 200 different keyhole escutcheons in a variety of styles in both iron and brass.
Escutcheons can be divided into two distinct categories. Surface mounted types that are simply pinned or screwed over the keyhole and "Thread" escutcheons that are mortised into the keyhole and show as a keyhole shaped brass line (thread). A third style called the flanged thread escutcheon has attributes of both, its body is mortised into the keyhole while it's bead-like flange sits on the surface.
Surface Mounted Escutcheons
Surface mounted escutcheons are by far the easiest to fit. The escutcheon is pinned into place and can cover a relatively crude job of keyhole cutting. Surface mounted escutcheons are often made to match a handle so a unified design can be realized.
Modern locks can make surface mounted escutcheons harder to use. Older locks tended towards a greater distance to the key pin (usually an inch or more), modern locks are generally nearer 3/4". If a surface mounted escutcheon is to be used with these modern locks be careful to avoid an overcrowded effect particularly on crossbanded or cockbeaded surfaces (we can supply a very nice lock with the 1 1/8" distance to pin dimension, item #: 168LC1).
If no suitable surface mounted escutcheon is available or a simple elegance is desired then consider a thread escutcheon. Select a thread escutcheon based on its visual effect on the furniture rather than the fit of the key. Older locks often used keys with bigger bits than those common today so larger escutcheons were more common on period furniture (our 180E4 instead of 180E5). Installing a thread escutcheon is straightforward though not as easy as fitting a surface mounted escutcheon.
Flanged Thread Escutcheons
Flanged thread escutcheons can be attractive and do not need the degree of precision fit required of a thread escutcheon. Due to their greater vulnerability they are usually fixed with small pins through holes both up and down into the surrounding wood.