Since I was talking about restoring doorknobs and back plates the other day I thought I might also mention Mechanical Doorbells. Now we are all familiar with the modern doorbell but quite frankly nothing spoils the look of a period restoration of an entry more than a bright back lighted doorbell.
We all take doorbells for granted but before the modern doorbell there is what was known as Mechanical doorbells. Now if you have ever restored an old house you may notice sometimes on the front door you may come across a filled hole in the center of the door. This is likely from a mechanical doorbell.
Mechanical doorbells were an alternative to the earlier 'door knocker". Essentially the Mechanical doorbell was a Small know that was connected to a rod. This rod went through the door (sometimes you will also see them in Door Trims) and connected to a bell on the other side of the door.
When you turn the twist knob the Bell on the inside rings much like a wind up alarm clock. These cam in a variety of styles and often matched the door knob. Finding matching set today is almost impossible.
You can often find mechanical doorbells though salvage companies and antique dealers. Fortunately for today's restorers these are now being reproduced by rensup and other historical hardware manufacturers. Prices range from 45.00 to 250.00
I "lucked out" about 10 years ago when I bought a box full at an auction of an old hardware store for a dollar. You can also find originals on Ebay, prices range from a few dollars to hundreds depending on how elaborate they area. If you have an original most clock restorers can clean and oil it for you at a nominal cost.