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Jason Pitsch

Arnold & Son Constant Force Tourbillon Hands-On

Jason Pitsch

August 23, 2015

Arnold & Son has created a patented constant force tourbillon which is powered by the two mainsprings visible at the top of the dial. A constant force device is used to equalize the amplitude (and therefore the chronometry) of the watch regardless of how much power reserve is remaining in the mainspring barrel(s).

Like a constant force device, a tourbillon aims to improve chronometry (timekeeping/accuracy), although it does is by compensating in gravity, as opposed to controlling the power delivery. As the mainsprings unwind and smoothly deliver power to the tourbillon regulating mechanism, this in turn powers the hours, minutes and most notably the dead beat seconds hand (located in between 6 and 9 o’clock). For reference, a dead beat seconds hand is an additional complication that makes the seconds hand tick like a quartz seconds hand versus the smooth sweep that is common in virtually all mechanical watches.


The hand-wound 3Hz movement (caliber A&S5119), features 39 jewels and has a 90-hour power reserve. Its components are made of nickel-silver and steel, with palladium treated bridges and a NAC treated main plate. Bridges are hand chamfered with polished edges and brushed surfaces. Additional touches includes screwed gold chitin and screws with bevelled and mirror polished heads. The tourbillon cage is mirror polished with hand chamfered polished edges and circular satin-fisnihed surfaces.


A 46 mm diameter red gold case with cambered sapphire crystal and see-through caseback houses this superbly decorated and technically unique movement, while allowing views of the components at work from both sides. Water-resistance is 30 meters and the watch comes with a hand-stitched brown bottier alligator leather with patina. Limited to 28 pieces. (Ref. 1FCAR.B01A.C112C)

Final Thoughts

This is a ridiculously technical movement, as we’ve come to expect from Arnold & Son. The constant force, the tourbillon and the dead beat seconds make for a very nice combination.

For more, visit Arnold & Son.

Arnold & Son, Baselworld, Hands-On

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