ORIS – Big Crown X1 Calculator

With its Big Crown collection, Oris demonstrates expertise in the field of tribute watches to historical aircraft. Inspired by the Bell X-1, the first plane to break the sound barrier, the Big Crown X1 Calculator refers to this era when flight plans were still made using slide rules, and accentuates this unique mechanism. Its rotating bezel serves to adjust the slide rule and to calculate fuel consumption for a given flight time, while the caseback displays a m/ft conversion table for international use. The chronograph push-pieces bear the X and 1, like a last nod to the date of the historical feat accomplished at 10:18 on October 14th 1947

Automatic, ETA Valjoux 7750

Hours, minutes, seconds, day, date, chronograph and slide rule

PVD-coated gunmetal grey stainless steel, 46 mm
Sapphire crystal cambered on both sides with anti-glare treatment on both sides
Screw-in caseback with mineral crystal and m/ft scale
Rotating bezel with circular slide rule
Water-resistant to 30 m

Metallised black/grey
Superluminova-enhanced minute-circle, hour-markers and hands
12-hour, 30-minute and small seconds counters at 6, 12 and 9 o’clock respectively
Date window between 4 and 5 o’clock and day window at 9 o’clock

Black calfskin leather

I’ve just posted a video review of my Oris TT1 Pro Divers Regulator 1000m, also known as “Der Meistertaucher”. I took this watch with me on a vacation, and it performed wonderfully. Fantastic water resistance and the lightweight titanium makes it very comfortable to wear. Features a 44mm diameter, and helium escape valve. Movement is a ETA2836-2 base movement modified and called the Oris 649.

I picked up this 1000m TT1 Regulator used on Timezone and it has become one of my favourite beater watches. This specimen has some scratches on the bezel, and I decided against sending it back to Oris for replacement. As a beater watch, I figured I would be getting scratched anyway, and I would care less about dings and dents if I just left it the way it is.


The case on the all-titanium Oris TT1 Regulator measures 44mm in diameter, but wears perhaps a tiny bit smaller due to the signature Oris case shape, which tapers from the back to the front. The bezel is uni-directional, and has a red 15-minute segment, with the rest in black.


Luminous markers are very bright and are charged very quickly. The small hour hand is luminous as well as the second, hour and minute indicators but the hour hand is more difficult to read, while the large minute hand obviously stands out and is easy to read. This makes the watch slightly more difficult to read than a traditional centre mounted layout. The second hand is not luminous, oddly.


This model is the newer version with the wave-pattern dial, in matte black. Date window is at 6 o’clock and has nice bevelled edges giving it a very completed and professional look. The crown is located at 4 o’clock and a helium release valve is located at 2 o’clock, giving the watch a balanced crown look that I really like. Another watch that has this look is the Doxa GMT. The Helium release value has a red dot on the top to differentiate from the crown. The helium release valve aids in allowing the watch reach depths of 1000 meters.


The Oris TT1 Titanium watches are one of the few rare Titanium watches on the market that have a polished finish. The Case is a two-tone polished/brushed combination, with the center links on the bracelet being brushed, and the outer links polished.


While the case is Titanium, it is not all that light compared with other Titanium watches I have owned. The bracelet on the other hand is extremely light and feels almost a bit cheap because of the weight. The quality of the bracelet is so-so, kind of a medium quality bracelet with good finish, but the pins bend easily when it is sized, and the clasp is not a solid as it could be, however these are minor points.


Movement in the watch is an in-house modified ETA Caliber, which Oris does a good job with. Oris offers excellent value with their modified movements. Oris watches keep excellent time and have recognizable and unique designs.

Overall the Oris TT1 Regulator Diver is an excellent choice if you can live with the Regulator layout of the dial. The watch is light and comfortable, and has served me well since I purchased it.

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