Today clock keys is the term applied to the key to wind a clocks mainspring and or set the time. Strictly speaking the term winder in horology is the correct term. A key is used to open and close locks. And as many clocks and chronometers have both locks on the cases and winding mechanisms confusion can arise. The clock key, the essential external and removable clock part and so also the most frequently worn and lost.
Clock Keys Style
There are many different styles of clock key. The styles form generally follows function. Although fancy keys for fine and decorative clocks manufactured in keeping with the clock are popular. Utilitarian steel keys the most widely used choice and representing the best value money. Brass keys are more in keeping with many styles of clock. Longer crank handled keys make winding the strong springs in larger clocks an easier task. Also carriage clock keys manufactured double ended because the clocks feature a time setting arbour different in size to the winding arbour.
What Size clock key do I need?
To establish which size of key your clock requires you will need to measure the width of the square winding pinion with a vernier gauge or similar in millimetres and purchase a key that is just a little larger. Consider the arbour tapers and generally the older the clock the greater the taper so the key needs to fit up the arbour not only the end. A tight fit avoids both slipping and wear while winding.
Clock Key Conversion Charts
We provide both the traditional number size and the size in millimetres for all keys so you can be sure of the keys exact size. There have been many numbering systems over the centuries. Also multiple conversion charts compressing and compromising the systems so less reliable as the exact size in millimetres. And also many imported keys we have found to use different number systems to British standard sizes. So please rely on measuring the size of the clock winding pinion in millimetres and not old keys or old conversion charts.
All the British Keys in our store use the following size system. We have a variety of styles of key in a range of sizes available in our store.
Clock Key Size Chart (British Sizes)The sizes detailed on this conversion chart are the British size keys we supply. Not all sizes are suitable for all styles of clock. So each style is only manufactured in sizes suitable for their general application in regards to winding clocks. Where there is no exact conversion the space is blank. Filling in the blanks is why so many conversion charts are inaccurate.