Montres Karsten Frässdorf
German master watchmaker Karsten Frässdorf founded Montres KF in La Chaux-de-Fonds in 2016, having previously worked for Fabrication de Montres Normandes, Heritage Watch Manufactory, and Leroy. Every watch is 100% developed, produced, and assembled in La Chaux-de-Fonds, and made entirely to order — bespoke only.
The signature Spirograph and EI8HT models feature the in-house Novamag® Calibre 01, a hand-wound one-minute tourbillon with a patented Spirograph® balance adjustment system (three patents), beating at 18,000 vph with 66-hour power reserve on twin barrels. Signature honeycomb dials can be specified in any colour, finish, or natural stone; hands, indices, even the crown can be personalised. The tourbillon is engineered to be shock-proof and anti-magnetic for daily wear.
The Spirograph balance at the heart of the Novamag Calibre 01 revives an idea with real pedigree: the compensating balance wheel pioneered by Pierre Le Roy and John Arnold after John Harrison's 18th-century breakthroughs in chronometry, reimagined for the 21st century. Frässdorf's version breaks the balance rim at two points, pairing an anti-magnetic steel cross-bar that expands with rising temperature against a second bar of sapphire crystal, whose low thermal expansion redirects that force into the affix arms and pulls them inward — reducing rotational inertia and speeding the balance's oscillation to compensate for a weakening hairspring, with adjustable screws along both arms fine-tuning the degree of correction. The hairspring itself pairs a Phillips outer curve with a Grossmann inner curve for improved isochronism, and the whole assembly has now accumulated five patents. The 42mm Lady EI8HT extended the concept to a fully personalisable ladies' tourbillon and earned a nomination in the Ladies' Complication category at the GPHG in 2021, while faceted octagonal EI8HT cases in meteorite and other materials have become signature commissions in their own right. True to the Bespoke Only ethos, literally nothing is fixed: typeface, dial motifs, movement decoration, balance finish, crown, strap, and clasp are all decided anew with each client, meaning that in a house of barely two dozen watches a year, no two have ever been quite the same.