Dating an atmos clock
The humble 400 day clock is also known as an Anniversary clock (as it's supposed to run for a year on one winding), or a Torsion clock (a term I prefer but which is not widely recognised outside clock making circles) but all three terms are interchangeable.An advantage to the collector is that 400 day clocks are largely unloved and under-rated and often, therefore, ridiculously cheap.It costs about £30 but another excellent book for general repair technique is Joseph Rabushka's 'Repair and Restore your 400 Day Clock' (about £15). Another source of information for repairers is Mervyn Passmore's automated Anniversary clock identification system - which is FREE!Unless there is something special about it, my flat rate for servicing one of the German anniversary clocks is £150 but if someone else has tinkered with it first that might increase because it can take me twice as long to correct someone else's mistakes, especially if they have re-bushed any pivot holes, moved the pallets or worst of all turned the eccentric screw that supports the escapement arbor.I don't lacquer it afterwards but I will wax it to protect the finish.
Some of the prominent Torsion clock makers include Gustav Becker (Image 1), Jahresuhrenfabrik ("JUF" - who coined the 'Anniversary' name and also produced a larger "bandstand " version as in Image 2), Kienzle, Kieninger & Obergfell (Kund O), Badische Uhrenfabrik (Image 3) and Phillip Haas.
The Anniversay clock is much maligned and the majority of repairers avoid them because they need additional effort and focus.
Also, they do not fully understand the pallets set up is different in these clocks, and so they struggle to set them up.
I won't charge for resetting (once) but you must bear the cost of postage both ways. If you're looking for information on a more sophisticated type of torsion clock, visit my page on Jaeger Le Coultre ATMOS clocks.
When I first started my antique clock collection, the first thing I noticed was how little I knew about the clocks I had.
The French firm Claude Grivolas also made 400 day clocks mostly with integral case rather than under a glass dome.