Just what exactly is the bushing, and how does it work? Well, it's simply a small ring that is flattened at the top. You slide it over the "chimney" of the key cup (and on top of the pad) and press it into place. It keeps the pad secure by the force of friction. Similar to the "chimney" in the open hole cup, a closed hole cup has a central "spud." To hold a closed hole pad in place, the screw is fastened into this "spud" (with pad and washer in between). With both types of keys, shims are used at the very bottom of the cup to seat the pads correctly. Regardless of whether the key is open or closed, the shims are the same. So if you've ever wondered just how a pad can stay in a key without a center, now you know!
|Metal French bushings, pad washers, pad screws|
|Open hole key has a "chimney" in the center. Closed hole key has a "spud."|
|Key shims to seat pads. Shims are the same for both types of cups.|
|Just about to place metal French bushing in key cup. Closed hole key pad in place with screw and washer.|
|Bushing in place!|