Watch Calibers

by Watchking

In discussions with watch manufacturer employees the "caliber" question often came up. The word in French refers to a gauge or size and also "to calibrate". Both meanings show up in watch jargon along with a third meaning which is simply the numerical progression of models.

In terms of "size" many watch companies graded movements by size with caliber designations. Using the same logic as gun calibers there could be watch movements with slightly larger sizes but smaller caliber numbers and vice versa. This stopped when watch movements were being developed every month and many were the same size. Watch companies then went two different paths.

Some watch companies numbered each new movement with a new "caliber" number as it was being developed consecutively. Since most of the new movements offered no advantages or they were not patentable many of the numbers are not present in the line-up of watches offered by various manufacturers. This was the system at Omega and many other watch houses.

The second system of numbering watch calibers went something like this. A watch house decided that either quality or function were going to determine the first digit or letter in the watch movement's caliber designation, then the second digit or letter was going to be determined by the quality or size and so on. This meant that a salesman in a store could use the caliber designation when selling and there was a logical
progression of some sort.

For example a company could designate that its chronograph movements might have 3 digit "calibers", and the manual wind models might have their "calibers" beginning with 7 and the automatic models might begin with 8. Sometimes there is no logic. In the case of Valjoux for example the 7x models are manual wind and the 77xx models are both manual (like the 7733 and 7734) or automatic (like the 7750 and 7751). Other companies tried using the low (1-4) 3,4 or 5 digit numbers on lesser quality movements and the high (6-8) 3,4 or 5 digit numbers on their best quality movements, with other numbers being used for special function movements.

What it all comes down to is that collectors need to memorize certain movement caliber numbers if they are trying to buy quality movements in any brand of watches. The Omega cal 1010 is well known and was used in some Tiffany watches and the ETA 2892-2 is widely known as a quality chronometer capable movement.

The Zodiac caliber 88 21 jewel high frequency movement was one of the best items that Zodiac ever made and most of them went into Kingline Chronometers. The Jaeger LeCoultre 859 chronograph movement and the caliber 960 use their own internal numbering system although both are fitted to Reversos.

The photo on page 78 of the February 2000 issue of WatchTime shows Chronoswiss watches being categorized by their movement caliber numbers. Some are consecutive (and likely developed by Chronoswiss) and some are calibers used by other basic movement manufacturers and then transferred to Chronoswiss numbers. The only thing to say is that if you are a very specialized collector then you should keep calibers in mind otherwise they are there to assist with watch repairs or to identify models to avoid.