Thursday, June 22, 2006

ETA Movement Grade Differences

ETA movements often come in four (or even five) flavours. It is important to know what you're getting as most manufacturers don't widely make it known to you which they're using. Some are more equal than others so to speak. The five flavours are Economique, Standard, Elaboré, Top and Chronomètre. Various choices of finish are available on all optionally*.

Economique, Standard and Elaboré have pretty much precisely the same components with subtle differences often surrounding shock protection, regulator (standard versus eccentric, etc)*.

However, Elaboré is regulated in three positions to tighter tolerance (see below) than the standard version which is regulated in two positions. The three positions are: dial up, 6H and 9H. Note that this is thus mostly acceptable for a watch worn on the left wrist! Regulation at 9H is not performed for the standard grade.

Top and Chronomètre have precisely the same components and are regulated in five positions (6h, 3H, 9H, FH dial down and CH dial up). Components different to Standard and Elaboré are at least as follows: Balance, balance spring, regulator, shock mounting, pallet stones.

Typical popular ETA movement standards:

Standard (regulated in two positions)
Mean daily rate +/- 12 s/d
Max variation across 5 positions: 30 s
Isochronism (rate after 24H running compared to full wind in dial up or CH): +/- 20 s/d

Elaboré (regulated in three positions)
Mean daily rate +/- 7 s/d
Max variation across 5 positions: 20 s
Isochronism: +/- 15 s/d

Top (regulated in five positions)
Mean daily rate +/- 4 s/d
Max variation across 5 positions: 15 s
Isochronism: +/- 10 s/d

Chronomètre Version to COSC specification.

*You can practice your French looking at an example catalogue of options for one movement shown here for the ubiquitous 2824-2 (pdf file). Also look here (I cannot post the link because it is an https site):

The moral: Contact the manufacurer before you buy to confirm the level of movement. Assuming they are telling the truth.......

Additions and corrections to this are most welcome.

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