Oris surprised many watch enthusiasts in 2020 when it introduced its in-house automatic movement, Cal. 400. The following year, in 2021, the company is busy expanding the 400 series of movements, releasing a derivative caliber. In this article, we will explain the features and appeal of Cal. 400, such as its long power reserve and high magnetic resistance, and then introduce the new 21 models equipped with this 400 series movement.
Aquis Date with Cal. 400. Cal. 400 has been downsized. The case diameter has been reduced by 2mm, and the dial color variations have been expanded. Automatic winding (Cal. 400). 21 jewels. 28,800 vph. Power reserve of approximately 120 hours. Stainless steel (diameter 41.5mm). Water resistant to 300m. Price: 374,000 yen (tax included).
Photographs by Masanori Yoshie
Interview and text: Yuto Hosoda (Chronos Japan)
Text by Yuto Hosoda (Chronos-japan)
Article published on June 2021, 6
Oris' high-spec in-house automatic movement, Cal. 400
Many people were surprised when Oris announced its in-house automatic movement, the Cal. 400, in 2020. Of course, the company, which released its in-house manual-winding movement, the 110 series, in 14, has the know-how to develop in-house movements, and also has the suppliers to make it happen.
However, it is noteworthy that Oris, which had built a good relationship with Sellita and relied on Sellita's ébauches for its automatic movements, decided to steer towards new development. What was most surprising was that the Cal. 400 is not a replacement for an existing ébauche, but rather a high-spec automatic movement with a modern design.
120-hour power reserve and 10-year overhaul cycle
The first thing that catches your eye when you look at the specs is the length of the power reserve. Until now, the power reserve of automatic movements such as the ETA2824-2, 2892A2, and their Sellita alternatives has typically been around 40 hours. In contrast, the power reserve of the Cal. 400 is nearly three times that, at approximately 120 hours.
This in-house automatic movement was announced by Oris in October 2020. It combines high-performance specifications with a strategic price.
It's true that in recent years, companies have begun to develop core calibers in anticipation of the ETA 2020 problem, and as a result, power reserves are becoming longer. However, most of these only last around 70 hours, meaning that even if you take your watch off on Friday night and don't wear it until Monday morning, it will still keep running. The fact that an automatic watch can keep running for about five days when fully wound is a major advantage in itself.
The Cal. 400 achieves this long power reserve of approximately 120 hours through two main approaches: the first is to increase the capacity of the power source, and the second is to improve the efficiency of power transmission.
The former was achieved by using a double barrel, which places two barrels to house the mainspring. The approach of increasing the amount of mainspring loaded is similar to that of the in-house hand-wound movement, Cal. 110, which uses an extremely large barrel to achieve a power reserve of approximately 240 hours (approximately 10 days).
The latter was achieved by redesigning the gears used in the gear train, which successfully improved the efficiency of energy transmission from the mainspring. By improving the meshing of the teeth, friction loss was reduced, raising the power transmission efficiency of the gear train to approximately 85%.
In addition to the long power reserve, the reduction in friction loss also brought great benefits to the Cal. 400. This meant that the overhaul cycle was extended. Not only was there less friction in the gears, but the escapement (escape wheel and pallet fork) was changed to silicon, which is less prone to wear and does not require lubrication, and the weight was reduced by removing the pallet stones in the pallet fork. These efforts reduced the load on the movement.
For this reason, Oris recommends an overhaul cycle for models equipped with the Caliber 400 every 10 years. In addition, they offer a 10-year quality guarantee from the date of purchase, provided that you register for the membership service "My Oris."
Silicon escapement provides magnetic resistance of 2250 gauss
In modern society, one of the essential specifications for a mechanical watch is magnetic resistance. Caliber 400 uses non-magnetic silicon for the escape wheel and pallet fork, and 30 other parts related to precision are made from non-ferrous or anti-magnetic materials, achieving a high level of magnetic resistance of 2250 gauss.
Although it does not have the same ultra-high magnetic resistance as a Master Chronometer, at approximately 15,000 gauss, it can be said to be sufficient considering that the standard for reinforced anti-magnetic watches is 200 gauss, and watches that use soft iron inner cases to prevent magnetism are around 1000 gauss.
The rational details that give the Cal.400 its unique character
One thing to look out for in-house movements these days is the regulator. High-end models and some mid-range models no longer have a regulator, but instead use a free-sprung balance, which adjusts the rate using a mass slot or weight attached to the balance wheel. This is because with traditional regulators, the regulator can shift when the movement is subjected to shock, affecting accuracy.
However, perhaps to keep the price down, Oris does not use a free-sprung movement. So, does that mean the Cal. 400 is vulnerable to shocks? Absolutely not. It uses a fine-adjusting regulator that is held in place by a rack and pinion. With this system, the regulator is engaged with a gear, so it will not fly off unless there is a significant impact.
Furthermore, the regulator has the advantage of allowing a wider range of rate adjustment than a free-sprung Masslot. This is a rational choice typical of Oris, achieving a balance between cost and performance.
The same can be said for the automatic winding mechanism, which is a rational design. Oris chose a unidirectional winding mechanism instead of a bidirectional one because, according to the company, "it reduces wear on the winding mechanism and requires less maintenance." Additionally, unidirectional winding ensures reliable winding even in situations with little movement, such as desk work. The rotor itself also uses a sliding bearing instead of a ball bearing, which is also less likely to be subjected to stress and is therefore more durable.
Both choices emphasize rationality, but the depth of the Cal. 400 lies in the fact that these are reflected in the movement's individuality.
