Presented for auction by Second Vintage A beautiful example of mid-century horological innovation, this Hamilton Thin-o-matic captures the elegance and technical ambition of its era. Powered by a fascinating micro-rotor movement, this timepiece offered a remarkably slim profile without sacrificing the convenience of automatic winding. With its classic proportions and distinguished patinated character, it stands as a testament to Hamilton's golden age of watchmaking. Brand: Hamilton Model: Thin-o-matic Serial Number: S999681 Movement: Automatic micro-rotor caliber 620 Dial: Silver sunburst with applied gold-tone indices, showing noticeable even spotting and vintage patina Case Size: 33 mm (excluding the crown) Case Material: 10k Gold Filled Production Year: 1960s Condition: Good vintage condition with honest wear and distinct dial patina Dial and Hands The silver sunburst dial features a classic mid-century layout with applied gold-tone Arabic numerals at the quarters and faceted dart indices for the remaining hours. An applied Hamilton logo sits proudly below the twelve o'clock position, accompanied by crisp black typography including the signature Thin-o-matic script. The dial exhibits significant, even vintage spotting and speckling across its surface, creating a distinct and authentic aged character that collectors often refer to as stardust patina. The original dauphine hands show heavy oxidation and darkened aging, perfectly matching the overall vintage aesthetic of the watch. Case and Crystal The 33 millimeter round case is crafted from 10k gold filled material, presenting a warm and elegant tone. The slender straight lugs retain their classic profile, while the polished bezel and case flanks display moderate surface scratches and honest wear consistent with decades of use. The original Hamilton-signed crown, featuring the distinct logo, remains intact and functional. A domed acrylic crystal protects the dial, showing minor surface handling marks but offering a clear and unobstructed view of the vintage display beneath. The solid caseback snaps securely into place and features internal factory engravings confirming the gold-filled construction and serial number. Movement Inside beats the fascinating Hamilton caliber 620, a Swiss-made automatic movement renowned for its micro-rotor architecture. This innovative design allows the automatic winding mechanism to sit flush within the movement plates, significantly reducing the overall thickness of the watch. The copper-finished plates are clearly signed and feature seventeen jewels. Exhibiting remarkable accuracy and consistency, performing brilliantly for a vintage timepiece. The timegrapher results indicate an exceptional performance of +5 to +10 seconds per day. Strap The watch is fitted with a handsome black leather strap featuring an embossed alligator pattern and matching black stitching. The strap is secured with a classic polished tang buckle, complementing the gold-filled case and providing a comfortable fit for daily wear. Condition Good vintage condition. The case shows normal signs of wear with moderate scratches and softened edges typical of a well-enjoyed gold-filled timepiece. The dial and hands display heavy honest patina and spotting, giving the watch a strong vintage character without compromising legibility. The movement is remarkably clean and running exceptionally well. Dimensions The watch measures 33 millimeters in diameter excluding the signed crown. The slender profile and classic lug design ensure a refined and comfortable presence on the wrist, staying true to its Thin-o-matic namesake. Remarks This Hamilton Thin-o-matic represents a compelling intersection of elegant mid-century design and important mechanical innovation. The micro-rotor movement remains a highly collectible feature, offering the charm of vintage mechanical watchmaking in an incredibly wearable package. History Founded in Lancaster, Pennsylvania, in 1892, Hamilton became a cornerstone of American watchmaking, initially famed for its highly accurate railroad pocket watches. By the mid-twentieth century, Hamilton had transitioned into a powerhouse of innovative wristwatches. The Thin-o-matic line, introduced during this era, utilized micro-rotor technology developed in partnership with Buren. This allowed Hamilton to offer automatic watches with a significantly slimmer profile than traditional center-rotor automatics, cementing the brand's reputation for blending technical advancement with sophisticated design. Payment and Shipping Payment must be completed within 1–3 days after purchase. Your watch will be professionally and very securely packaged, and shipped with tracking and insurance for your peace of mind. We ship via fast express service, with typical delivery in 1–4 business days (destination dependent). Note that with vintage watches, minor signs of wear, aging, or imperfections may be present and are considered normal for watches of this age. Please review all photos carefully before bidding. We strive to photograph each watch from multiple angles for the most accurate representation. The photos form an important part of the description. If there are any concerns of functionality or defects after delivery, make sure to contact us within 3 days of receiving the watch so we can assist you. As with all vintage watches, water resistance is not guaranteed. If you have any questions, feel free to contact us after the auction ends. / Second Vintage SKU: HAM-TDT-0001