A pocket watch should be cleaned and oiled once every twelve to eighteen months and a wrist watch from every six to ten months.  For this purpose take it to a jeweler in whom you have confidence and who is an expert watchmaker or who employs one. The proper cleaning of a watch is not a perfunctory job to be done in a few days. A watchmaker will take the watch movement apart.  He will then wash in benzene all the jewel mountings, jewels, screws, wheels, balance, etc., to remove accumulated dirt and old oil. After this operation, the parts are thoroughly washed in a special soap solution, cleaned in cyanide, again with soap and water and finally immersed in alcohol and properly dried.  Each of the parts is then separately polished and reassembled. All bearing surfaces are carefully oiled with the best grade of watch oil. A skilled watchmaker, in fact, does exactly what the skilled watchmakers of the Hamilton factory do when they “finish” a watch for delivery.  It may be that your watch at the time of cleaning has accumulated very little outside dirt, but the oil may have gummed to a certain extent. This, if not removed, will have a tendency to slow up action and so cause variations in time. It will also cause wear on the delicate pivots which rest in the jewels.

The following table can be followed in having your watch examined, cleaned, and oiled:

• 16 size railroad watches or watches of larger size – every 12-15 months
• 12 size thin models – every 12 months
• Men’s wrist watches – every 10 months
• Ladies’ wrist watches – every 6-8 months

Have you ever noticed how the bearings of a motor car run in bronze bushings?  It is a well known mechanical law that to gear the same metals together or to permit similar metals to wear on each other is to court disaster.  Metal-to-metal wear is reduced when the metals are of different character. Thus, you will find the gold or brass wheels run into steel pinions and that in high-grade watches jewels are used as bearings for the pivots, escapement, balance, and other parts. It is a quite common impression that jewels are placed in a watch movement for the purpose of ornament.  As a matter of fact, they are placed there for the very important purpose of wear-proof bearings.  They have a fundamental and practical value in a watch. They are, in fact, so important that they are a gauge of a watch’s quality.  So it is that watches of 17 jewels or more are considered high-grade watches. All Hamilton watches have 17 or more jewels.