Key Help

Clockworks gets many phone calls and emails from customers asking for key help. They want to know what size a certain movement takes. Unfortunately, there is only one way to know for sure what size to get. Measure the shaft in which the key is to go on in millimeters. Then match that size in the clock key chart to see what size to get. This is the only way to know the exact size. One thing that can be said. German movements post World War II have a general rule of thumb. Square or rectangle movements take a number 8 key and round movements take a number 4 key. American clocks made from around 1875 until after the second war almost always take a size 7. This size fits the 8 day time / strike units pretty much every time. This is what USA made the most of. This rule may not apply to Westminster (3 places to wind) or time only (one place to wind) clock movements.