The Rolex Oyster Perpetual Date, particularly the reference 5500 produced from the late 1970s, often features the caliber 1520 movement. However, within this seemingly singular designation lies a subtle but important variation: the number of jewels. This article will delve into the differences between the Rolex 1520 17J and the 1520 26J movements, exploring their history, technical specifications, and ultimately, helping collectors and enthusiasts decide which, if presented with the choice, is the better option. Our discussion will draw upon information gleaned from various sources, including vintage Rolex forums, dedicated Rolex movement databases, and anecdotal evidence from collectors.
17J vs 26J: A Tale of Two Jewels
The "J" in 17J and 26J stands for "jewels," referring to the synthetic ruby or sapphire bearings used in the movement. These jewels reduce friction, allowing for smoother operation and increased longevity. While both the 1520 17J and 1520 26J movements are variations of the same basic caliber, the difference in jewel count reflects a significant evolution in Rolex's manufacturing processes and design philosophy.
The 1520 17J movement, generally found in earlier production runs of the reference 5500 and other models utilizing this caliber, represents a more streamlined, cost-effective design. With fewer jewels, it was likely intended to offer a reliable and robust movement at a more accessible price point. This doesn't necessarily mean it's inferior; many 17J movements have proven remarkably durable and accurate over decades of use. However, the reduced number of jewels might suggest a slightly higher degree of friction in certain components, potentially leading to marginally increased wear over time. Anecdotal evidence from vintage Rolex forums suggests that maintenance intervals might be slightly shorter compared to the 26J variant.
The 1520 26J movement, on the other hand, represents a refinement of the 1520 design. The additional nine jewels indicate a greater emphasis on minimizing friction and enhancing the movement's overall efficiency and longevity. This increase in jewels often translates to smoother operation, potentially leading to improved accuracy and reduced wear on critical parts. The extra jewels are strategically placed in areas where friction is most pronounced, minimizing the wear and tear on pivots and other moving parts. This results in a movement that's arguably more robust and potentially requiring less frequent servicing.
Caliber 1520 Jewel Variations: A Matter of Evolution
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