Expert: Martin Meyer - 1/24/2009

Question
I have recently cleaned and oiled a pendulum chiming clock and am having trouble getting it to maintain regular time. The escapement pallets were the only items removed for cleaning. It should run for 7 days, but starts to slow down after 3 days unless fully rewound. I am nonplussed

Answer
Hi Frank,

Your question seems to imply that this is a mainspring, rather than weight, driven clock. Mainspring barrels are rarely completely sealed, and usually have a small cutout notch in the cap or, at least, are not watertight. If the movement was immersed in a cleaning solution, the solution was probably not entirely removed from the mainspring barrels, and the mainsprings may be gummed up and sticking.

Aside from that issue, and assuming that you are always winding the mainsprings all the way as far as they will go, the problem could be in your cleaning method, in the adjustment of the verge (pallets) when the clock was reassembled, or the mainsprings could be worn out and need replacement.

Cleaning a movement without completely disassembling it is never a recommended procedure. It is difficult or impossible to clean the tight spaces between the pivots (shaft ends) and their holes in the main plates. Assembled cleaning often merely moves the dirt around and sometimes works it even more deeply into these bearing clearance spaces. Additionally, dried oil under the pressure of the moving gear shaft pivots forms a varnish-like and very hard residue in the bearing holes. This must be removed by "pegging out" the bearing holes with clockmakers pegwood. Therefore, it is not unusual for a clock to actually run worse after assembled cleaning than it did before.

Finally, the verge adjustment must be extremely precise, and removing the verge loses all adjustments. It is essential that the pallets lock at the correct depth on the escape wheel teeth, that the drop of the pallet from one tooth to the next be correct, and that the drop be equal between the two pallets.  http://www.clockmasteronline.com