Introducing Our 40 mm Pocket Watch Conversion Case
At Frett and Co Clockworks, we believe the soul of a watch is the movement—and our conversion cases are designed to honor that belief. With the launch of our new 40 mm case, we’re bringing the same attention to detail, engineering precision, and historical respect found in our 44 mm platform to a smaller, more compact form—purpose-built for American 6-size pocket watch movements.
40 mm case in 316L stainless with front and back sapphire, coined edge, and 50 meters water resistance.
Made for 6s Movements: Smaller Format, Same Philosophy
6s American pocket watch movements may be smaller in diameter, but they’re every bit as worthy of display as their larger counterparts. In fact, many 6s calibers feature some of the most intricate finishing work and dial designs ever produced during the golden age of American horology. Our 40 mm conversion case gives these elegant movements a modern wrist presence while preserving their vintage character.
Sized at 40 mm across with a 48 mm lug-to-lug and a 20 mm lug width, this case offers vintage-friendly proportions that wear effortlessly—perfect for smaller wrists or collectors who prefer a more traditional fit.
Our 40 mm case with a 48 mm lug-to-lug and 20 mm lug width offers vintage proportions that wear naturally on the wrist—ideal for collectors who prefer a classic fit.
Shared DNA: A Design Language Rooted in Craft
While the 40 mm is a completely new platform, it carries the visual and structural hallmarks of our 44 mm case. Most notably, both share our signature coined-edge—a defining feature that ties the two platforms together and reflects our consistent design language.
This subtle but intentional continuity ensures that no matter which case size you choose, you’re getting a watch that reflects the Frett and Co approach: clean lines, precision-built components, and historical fidelity without unnecessary embellishment.
44 mm case with signature coined edge.
40 mm case with signature coined edge.
316L Stainless, Domed Sapphire, and Anti-Reflective Clarity
Crafted from 316L stainless steel, the case is built to last while retaining a refined look. The coin-edge bezel adds texture and visual interest, grounding the modern build in traditional watchmaking design.
Both front and back sapphire crystals are anti-reflective coated for optimal clarity. The domed front sapphire crystal echoes the feel of original mineral crystals found on most vintage pocket watches, offering warmth and visual depth while delivering superior scratch resistance and optical performance.
Domed front sapphire crystal—AR coated for clarity, shaped to echo the warmth and depth of vintage mineral glass.
Exhibition caseback with AR-coated sapphire—built to showcase the beauty of the original 6s movement in full detail.
Flip it over and take it in—sapphire caseback gives you a crystal-clear view of vintage American watchmaking at its finest.
Water-Resistant for Real-World Wear
Like our 44 mm case, the 40 mm platform is fitted with crown, bezel, and caseback gaskets to ensure water resistance up to 5 ATM (50 meters). This makes it a true daily-wear option—no need to baby it. From rain to handwashing, it’s ready for everyday use while still protecting the legacy inside.
Not Just Smaller—Purpose-Built for 6s Movements
This case isn’t a scaled-down afterthought. It’s a completely re-engineered frame, tailored specifically to the dimensions and proportions of 6s movements. That means every aspect—from case thickness to crystal curvature to crown clearance—was carefully considered to bring out the best in these historically significant movements.
Have a 6s Movement Worth Wearing?
Whether you want to convert a family piece or restore a forgotten movement from your collection, our 40 mm case brings it to life—modernized just enough for daily wear, but with all the soul intact. Explore our ready-to-wear builds or reach out for a custom project. We’d love to help you tell its next chapter.
