HAND SETTING KNOB 8mm BRASS Requires 3.25mm hole. Maximum glass thickness 3mm. Put a felt or paper washer between theknob and glass and rivet in place.
The setting knob is designed to avoid Parallax errors on fine barometers. The setting hand needs to be as close as possible to the dial and this is normally done with a very thin hand, normally around 0.3mm thick. A paper or felt washer is put between the glass and the knob and a blind punch is used to spread the shaft to retain the hand without a washer.
Some barometers are more of a decorative item than a barometer and the distance between the setting hand and the dial can be excessive. It seems to stem from the fact that whereas a clock should be accurate, it's quite acceptable for the barometer to be pointing at Dry while its raining! These decorative barometers can have thick hands and a washer to make the job of fitting the hand less likely to break the glass.
BOUTON DE REGLAGE D'AIGUILLE 8mm. LAITON Nécessite un trou de 3.25mm. Epaisseur max. du verre : 3mm. Mettre une rondelle de feutre ou de papier entre le bouton et le verre,et ensuite riveter.
ZEIGER EINSTELLKNOPF 8mm MESSING Legen Sie eine Filz- oder Papier-Unterlegscheibezwischen dem Knopf und Glas und vernieten Sie diese.
ENGANCHE PARA LAS MANECILLAS 8mm LATON Ponga un fieltro o una arandela de papel entre el enganche y el cristal y remacen el lugar apropiado.
PARALLAX
You are in a train station and your train departs at 6 o'clock. You go to platform 10 but the man at the barrier tells you that you need platform 1 not 10.
There is a clock above platform 5. It's not a very good design because the minute hand is a few inches away from the face. From platform 1 it says 1 minute to 6 so you run to platform 1.
You stop at platform 5 to check the clock but it now shows 1/2 a minute to six! You run frantically to platform 1 and the clock now says 6:00 but you only took a few seconds to get there. You ask the lady at the barrier if you have missed the train. She looks at her digital watch and says 'No dear, you have 20 seconds... All because the gap between the hour hand and the clock face was unnecessarily big, creating a Parallax error.
