New Standard: Reviewing the Oris Aquis Date Calibre 400

After a development period of five years, Oris launched its new in-house movement with 10-year recommended service intervals and a 10-year warranty. The movement, the Calibre 400, further runs five days and offers increased antimagnetic protection. It debutted in the modern Aquis Date dive watch, a timepiece that represents the essence of the brand, which we revisit today in our latest visit to the WatchTime Archives in the story below from Fall 2021.

Oris Aquis Caliber 400

At first glance it looks like a “perfectly normal” Oris Aquis Date. It’s not immediately clear what awaits you inside. Immediately apparent is the well-known gradient dial that gradually changes from bright blue in the center to almost black at the edge. Surrounding it is the unidirectional rotating bezel that identifies the Aquis Date as a functional dive watch. The grooved ring ratchets in half-minute increments and has a dark blue, scratch-resistant ceramic inlay. This, along with the brightly glowing Super-LumiNova-coated hour markers and hands, is designed for safe diving.
On the lower portion of the dial, a second glance reveals the power-reserve indication of “5 DAYS,” just below the “30BAR/300M” pressure-resistance indication. It’s a rather discreet way to show the innovation in the Aquis Date that Oris calls “revolutionary” — modern Calibre 400. It’s clearly visible through the transparent threaded caseback. With its unique architecture — which does not include any of the “High-Mech” trademarks (like the red segment on the winding rotor) for which the Oris movements are known – it is clearly something new. In addition to the in-house hand-wound caliber series 110 to 115, new in-house automatic Caliber 400 will join the series movements from major suppliers like Sellita. Because it’s important to Oris to offer good watches at affordable prices, Caliber 400 will not replace existing standard movements, but complement them, and it won’t drive up the prices of the models equipped with it.

The Swiss brand chose the Aquis for the premiere of its new in-house base caliber.

Calibre 400 Suits the Brand and its Base
Oris developed the Caliber 400 movement in-house and tailored it exactly to match the character of Oris timepieces and the demands of its customers. This automatic movement was redesigned from the bottom up and every detail was put to the test. The goal was to design a highly efficient and robust movement, according to Beat Fischli, COO of Oris, who developed the new caliber with his team. It was created as a response to modern needs: offering the best possible quality at a reasonable price to give the customer real value and also to underscore the concept of sustainability, which Oris has pursued for years with numerous models and initiatives — ambitious goals within the Oris brand philosophy.

After a five-year development period, a movement was created that is based on a solid foundation that can be seen at first glance through the large, transparent caseback. Matte-finish bridges and a single fine finish on the skeletonized rotor give Caliber 400 a technically robust impression that is perfectly suited to the brand. The eye remains on the center of the movement and on the unique bearing of the automatic rotor. Oris has eliminated the ball bearing and replaced it with a smoothly running friction bearing, in which a steel shaft runs through an oiled bushing. Engineers discovered that problems occurred with the unidirectional winding mechanism relating to the ball bearing, which allows the oscillating weight to rotate freely. The winding system in Caliber 400 is unidirectional. It is less complex than a bidirectional winding mechanism but is still efficient and, thanks to the friction bearing, especially resistant to wear.

Oris Calibre 400
Power for 120 hours comes from two large sequential barrels.

The automatic winding mechanism provides two barrels with power, which can keep the movement running for five days when fully wound. The rate remains remarkably stable throughout. The amplitudes fall from an average of 300 degrees when fully wound to 240 degrees on the fifth day. To achieve this level of performance, two large barrels are needed with long mainsprings. The two barrels are arranged in series and are unmistakable, as they take up almost half of the movement. Each barrel stores 60 hours of energy. The system provides an efficient management of energy since the torque is low and thus the pressure on the gear train is reduced, which limits wear. The efficiency of the transmission of energy is also increased thanks to the new gear design. In total, the movement uses 85 percent of the power provided by the barrels. The average is usually 70 percent.

At the other end of the power line, we find a completely new escapement. The pallet fork and escape wheel are made of silicon and are meticulously matched to one another. Non-ferrous alloys were selected for the shafts, as well as for the balance wheel. More than 30 of the total 135 components are made of such materials. This generally reduces the effect of magnetism on Calibre 400 in comparison with conventional Swiss movements. Oris states this reduction as 90 percent. In collaboration with the Laboratoire Dubois testing lab, Caliber 400 was stress tested at 2,250 gauss for an entire day. Afterward, the rate deviated less than 10 seconds. In comparison, a soft iron cage, for example, like Rolex uses for its Milgauss, provides magnetic protection of up to 1,000 gauss. According to the current ISO 764 standard, a watch is antimagnetic if it does not deviate more than 30 seconds per day after exposure to 200 gauss. Apart from the fact that this range no longer seems up to date, the Oris Caliber 400 deviates less than a third of the specified rate at a load that is more than 11 times as high.

The Oris Calibre 400 runs for five days with a silicon escapement and the brand’s own fine regulator.

We conducted the following test in our office. For a period of time, we subjected the watch to a field of about 1,000 gauss, a level of magnitude that a soft-iron cage can withstand and one that a person might encounter in everyday life. During this test, the amplitude fell considerably, and the watch rate appeared disturbed. This is completely normal and something we’ve seen during other magnetic field tests (for example, with watches from Certina or Mido). The amplitude normalized completely only a short time after the field was removed. As the manufacturer specifies, the rate leveled off, with a deviation of -7 seconds. This inspires confidence and is definitely better than standard. After the magnetic field was removed, everything reverted back to the “green range.”

This range remains at about 3 seconds per day, which our Aquis Date Calibre 400 showed during the real-life test on the wrist, where it was generally fully wound. On the electronic timing machine, it showed a similar rate when fully wound. As the power reserve ran down, the rate remained stable on the second and third day, at about 2 seconds per day. On the fourth day, the watch showed no deviation at all, and only on the fifth day did it go into the minus range. These are very good results, including the amplitudes and positional differences, as mentioned earlier. The watch is adjusted with a proprietary Oris system, which has already been established in its in-house hand-wound movements: a screw-driven pinion engages with the curved rack to control the regulator.

Calibre 400 (shown here, the dial side) consists of 135 components, 30 of which are made of antimagnetic alloys.

A 10-year Warranty for Caliber 400
Oris is so certain of this advanced technology that the company is guaranteeing the Aquis Date Calibre 400 and all future watches equipped with this movement with a 10-year warranty. “The Caliber 400 is a new standard,” says Oris CEO Rolf Studer. “There is nothing comparable. Thanks to its structural solutions, we not only offer a 10-year warranty, but also a service interval that is just as long,” he added with justifiable pride, apart from the conventional water-resistance tests, which are essential for the Oris Aquis Date Calibre 400 as a professional dive watch.

Contributing to the specified water resistance of 300 meters are the threaded caseback and a screw-down crown, which is nicely protected by the screwed crown guard. In view of its dimensions and the large lateral grooves, the crown is easy to grasp and unscrew from its locked position. In the middle position it allows the wearer to quickly adjust the date. As usual, the date display appears at the 6 o’clock position — now with white numerals on a black ring, which goes well with the black tone of the gradient dial, and in a larger window. This means the date ring was enlarged and needs more power to advance. In everyday use, the date begins its visible movement about one hour before midnight and jumps almost exactly to the next position at this time. When setting the time, we noticed that the minute hand jumps slightly when the crown is pulled out. Here we used an old watchmaker’s trick: when setting the watch, first move the minute hand back slightly to ensure proper setting that is accurate to the second, thanks to the modern stop-seconds mechanism in Caliber 400.

Today, a modern watch needs a quick strap changing system. Oris offers one that is both simple and secure.

The Aquis Date Calibre 400 comes with a high quality steel bracelet and Oris’s own “Quick Strap Change” technology, which has become more or less standard these days, and not just for functional sports watches. Here, a sturdy flap is fed over the bar and locks securely in place with an audible click. A fingernail is all that’s needed to open and release it. In contrast to other systems, this inspires confidence as does the solid action of the folding clasp, which opens by pressing the two side push buttons and has an integrated, 20-mm dive extension. For those who prefer getting in the water with a rubber strap, the “Quick Strap Change” system works well. The length of the stainless-steel bracelet can be adjusted to the exact wrist size using several screwed elements at the clasp.

Calibre 400 Responds to Everyday Demands
The Aquis Date is a professional dive watch, down to the last link of its highly functional stainless-steel bracelet, and, for good reason, was selected as the first one to be fitted with the innovative Caliber 400. Sturdy, stylish, technically up to date and offered at a reasonable price, it embodies the Oris philosophy. Equipped with Caliber 400, it offers added value for its customer: stable rate results, high power reserve, reliable antimagnetic protection and long service intervals. It’s like a top athlete who combines a well-known image with new inner strength, at the top of its game, and easily responding to the demands of modern everyday life.

The folding clasp with side push buttons has an integrated dive extension.

Manufacturer: Oris SA, Ribigasse 1, 4434 Hölstein, Switzerland
Reference number: 01 400 7763 4135-07 8 24 09PEB
Functions: Hours, minutes, center sweep seconds, date, dive bezel, screw-down crown
Movement: Oris Calibre 400, automatic, 28,800 vph, 21 jewels, copper beryllium gold-plated balance, iron /nickel /chrome alloy hairspring, fine adjustment via two-part eccentric (with screw), Incabloc shock absorption, 120-hour (5-day) power reserve, diameter = 30.0 mm, height = 4.75 mm
Case: Stainless steel with curved sapphire crystals, domed on both sides, anti-glare coating inside (top), sapphire crystal in caseback, water resistant to 300 m
Bracelet and clasp: Stainless-steel bracelet, simple folding clasp with fold-out dive extension, with Oris “Quick Strap Change” system
Rate results (deviation in seconds per 24 hours, fully wound/after 24 hours):
On the wrist +3.1
Dial up +2.9 / -0.1
Dial down +4.8 / +1.7
Crown up +1.8 / +3.2
Crown down +3.9 / +1.7
Crown left +3.6 / +3.7
Greatest deviation 3.0 / 3.8
Average deviation +3.4 / +2.0
Average amplitude:
Flat positions 318° / 309°
Hanging positions 290° / 278°
Dimensions: Diameter = 43.51 mm, lug width = 25 mm, height = 13.27 mm, weight = 178.0 grams
Variations: With rubber strap (Ref. 01 400 7763 4135-07 4 24 74EB, $3,300)
Price: $3,500

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  1. Michael

    The article says this is a silicon hairspring but the specs below say not. Which is it?

  2. Gerardo Gregory

    I own a caliber 400 – 43.5mm – holds its power reserve as stated. It does take considerable manual winding to get both barrels wound if you allowed the watch to wind down. Looks stunning, wears very well.

  3. Bill Harding

    I bought one of these back in January. The watch looks superb but accuracy is appalling and the claimed 5 day power reserve is a joke. Mine hasn’t gone longer than 25 hours with either wrist or manual winding and last week it lost a full minute overnight. To say I’m disappointed is like
    claiming the Atlantic is wet..

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