Chronometer accuracy

[mrfunex]

Hi,

A watch I've had for a while (Ernst Benz Chronosport) had what I believe is the chronometer accuracy printout stuffed in the box. Could anyone shed any light on what these heiroglyphics actually mean?

The paper says:

POS        RATE      BEAT ERROR        AMPLITUDE
VB         +011      0.4               277
VG         +009      0.2               272
VH         +007      0.2               263
HH         +008      0.2               272
-------------------------------------------------
DEL        004       0.2               014
MOY        +009      0.3               271

Many thanks!

Edited by mrfunex on Sunday 15th November 17:14

[glazbagun]

Beat error is the difference between ticks- one for each direction of the balance. Ideally there should be no difference, which would mean that the balance impulse pin was unlocking the movement right in the middle of its arc. So tea, tea, tea instead of coffee, coffee, coffee.

Amplitude is how many degrees the balance is rotating through.

POS is the position the watch was tested in, with Rate being the time gained or lost per day in that position (approximated from a sample size of hopefully >20 secs)

DEL appears to be the range of deviation across the positions, with MOY being the average reading across positions.

IIRC, COSC "chronometer" spec is -4/+6, so your reading seems a little short of that, however it seems pretty consistent across positions, so shouldn't be too big a problem to lower the rate if you're that much of an accuracy freak.

Edited by glazbagun on Sunday 15th November 18:24

[mrfunex]

Many thanks for the detailed explanation! I'm not so fussed on overall accuracy, but it's good to know the error is consistent. I might get it adjusted when it goes in for a service.

Edited by mrfunex on Sunday 15th November 18:35