World of Watches (Singapore) - - Features -

The move­ment may lie hid­den within the case, but it makes its pres­ence felt in very pal­pa­ble ways, from the func­tions avail­able to the dial’s lay­out and the push­ers’ tac­til­ity. Vari­a­tions abound, but some op­tions are def­i­nitely pre­ferred over oth­ers here.

Switch­ing and trans­mis­sion

For a start, there’s the fa­mil­iar stomp­ing ground of a chronograph’s ac­tu­a­tion and cou­pling to con­sider. Ac­tu­a­tion refers to the “switch” that con­trols the chronograph. Cam ac­tu­a­tion uses the epony­mous com­po­nent, which is fairly easy to pro­duce and as­sem­ble, but has a draw­back of un­even tac­til­ity – the ini­tial force re­quired to start the chronograph is no­tice­ably higher than what’s needed to stop or re­set it. A col­umn wheel, in con­trast, is more dif­fi­cult to man­u­fac­ture and fin­ish than a cam, but prom­ises a smoother pusher feel akin to what gun en­thu­si­asts de­scribe as “snap­ping a glass rod” when they talk about a trig­ger’s tac­til­ity.

The cou­pling sys­tem de­ter­mines how the chronograph mech­a­nism is pow­ered by the base move­ment. In hor­i­zon­tal cou­pling, a wheel swings hor­i­zon­tally and en­gages with the base move­ment to al­low the chronograph to draw en­ergy from the gear train. This en­gage­ment can be pre­cisely ad­justed, since it’s a sys­tem of levers that can be vis­ually in­spected by the watch­maker. It has its dis­ad­van­tages though. For one, the con­nection puts an ad­di­tional load on the main­spring all of a sud­den. This re­duces the en­ergy sent to the bal­ance and hence its swing am­pli­tude, which af­fects isochro­nism. The mesh­ing of wheels also causes wear and tear, and leads to a chronograph sec­onds hand that’s prone to flut­ter and back­lash when the chronograph is first started. The ver­ti­cal clutch does not have these prob­lems, as the chronograph mech­a­nism is con­stantly en­gaged with the base move­ment, and started by fric­tional mesh­ing of two discs press­ing into each other ver­ti­cally. It’s con­sid­ered a bet­ter so­lu­tion but does, how­ever, de­mand more skill in reg­u­la­tion and ad­just­ment.

Quick ticks

A move­ment’s beat fre­quency typ­i­cally runs from 2.5Hz (18,000vph) to 5Hz (36,000vph) in mod­ern cal­i­bres. All else be­ing equal, a move­ment with a higher beat rate will be more ac­cu­rate, as the bal­ance gives more “read­ings” per se­cond, which av­er­ages out any er­ro­neous beat’s tim­ing to a greater ex­tent. This is why quartz move­ments, whose crys­tals vi­brate at 32,768Hz, are far more ac­cu­rate than me­chan­i­cal ones. A chronograph’s res­o­lu­tion cor­re­sponds to its beat rate – a 4Hz move­ment can mea­sure elapsed time down to 1/8th of a se­cond, while a 5Hz one goes to 1/10th of a se­cond. Taken to the ex­treme, this can yield mind­bog­gling re­sults like TAG Heuer’s Car­rera Mikro­girder, which beats at 1,000Hz to give a res­o­lu­tion of 1/2000 se­cond.

Fur­ther com­pli­ca­tions

Fly­back and rattrapante/split-sec­onds chrono­graphs are vari­ants on the sim­ple chronograph. The fly­back func­tion al­lows a chronograph’s re­set pusher to be ac­tu­ated while the chronograph is run­ning. This makes all its hands “fly back” to zero and con­tinue run­ning with­out lag – use­ful for tim­ing con­sec­u­tive events such as the legs in a plane’s nav­i­ga­tion pat­tern. The rattrapante chronograph has two chronograph sec­onds hands. Ac­tu­at­ing a third pusher stops one of them to al­low an in­ter­me­di­ate tim­ing to be read, and push­ing it again snaps it for­ward to catch up with the other in­stan­ta­neously.


The ideal move­ment for the ul­ti­mate sports chronograph should have the fol­low­ing: a col­umn wheel for smooth and con­fi­dent ac­tu­a­tion, ver­ti­cal cou­pling for greater ac­cu­racy and a pre­cise start to the chronograph se­cond hand, high fre­quency that’s both more ac­cu­rate and ca­pa­ble of mea­sur­ing smaller units of time, and split-sec­onds func­tion­al­ity to time si­mul­ta­ne­ous events that will ar­guably see more use than a fly­back func­tion.

Parmi­giani Fleurier’s PF361 has all of the above, but is lim­ited to just 50 pieces, and is con­structed in gold. Re­lax the re­quire­ments, how­ever, and more op­tions present them­selves. There’s Zenith’s El Primero, which re­mains the only high-beat chronograph move­ment in mass pro­duc­tion, but it uses hor­i­zon­tal cou­pling and is a sim­ple chronograph. Rolex’s Cal­i­bre 4130 is both col­umn wheel-ac­tu­ated and ver­ti­cally cou­pled, but beats at 4Hz and lacks a split-se­cond func­tion­al­ity. The list goes on.

Rolex’s Cal­i­bre 4130 with col­umn wheel and ver­ti­cal clutch TAG Heuer Car­rera Mikro­girder Parmi­giani Fleurier’s PF361 cal­i­bre in the Tonda Chronor An­niver­saire. Note the two col­umn wheels

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