Important Points for the Repair of a Connecticut-type American Antique Clock

I repair lots of American-made Connecticut-type antique clocks. This list helps me to remember everything important.

  • Check T1 and S1 tooth wear and record on log sheet. (Mainsprings are often too strong on these clocks, and I record the approximate wear each time I repair a clock to see if the teeth are wearing too rapidly);
  • If the mainspring arbor hooks have high backs, file them down to ease mainspring removal in the future. (Some clocks, especially Gilbert movements, have such tall mainspring arbor hooks that it is difficult to remove the mainspring from the arbor. Also, a too-tall hook can weaken the spring by pressing into it);
  • Check ratchets and clicks – do any repairs necessary. File burrs off underside of click. Tighten or replace click rivet if necessary. Make sure the clickspring is secure;
  • Check motion work and polish its pivots (by hand usually);
  • Chamfer the ends of pin that holds center tension spring;
  • Check lantern pinions – make a list of those needing new wires or wire reversal. Check for loose holes in shrouds that might let the wires fall out;
  • Check pivot holes – make a list of those to bush;
  • Check pivots – make a list of those to smooth with pivot file;
  • Check pins on gears – lock, warning, lift, etc. for tightness;
  • Check pins in plates for tightness and smoothness;
  • Check verge for wear. If you decide to move the escape wheel to bear on unworn pallet surface, do it now before pivot work;
  • Repair pinions first, then do the pivot work, then the bushing work.
  • Check for “tunneled” pivots. Chamfer (deepen) the oil sink if the pivot is too short. WATCH THIS ESPECIALLY ON THE SETH THOMAS NO. 124!
  • Use a smoothing broach to polish any pivot holes not bushed. Polish large pivot holes with a leather strip;
  • Test each wheel pair for proper depth and proper pivot hole fit. Assemble all wheels between plates and tighten down nuts and screws. Check endshakes and free rotation of wheels;
  • Check suspension spring – if it is merely dimpled at the top, punch a hole (use old staking set) and insert a flattened brass wire. (Use #22 soft brass wire, flatten it slightly, bend it partly, insert in hole, complete the bend and hammer it lightly);
  • Polish the suspension rod where the crutch embraces it. Be sure to smooth out any wear marks;
  • Polish the pallets if necessary (removing wear marks if bad). Install verge, test and adjust the escapement for drop (and lock for semi-deadbeat). Check crutch for tightness and adjust loop width;
  • If the movement has brass clicksprings, consider replacing them with steel (usually 22 gauge);
  • Clean the pivots of the strike lever arbors, smooth end of count hook. Smooth lifting surfaces. Replace the hammer leather if needed. (hammer the leather to harden it);
  • Make sure count wheel tension is not too great;
  • Push mainspring loop as far from mainwheel as possible;
  • If the strike train sounds “squeaky”: this can be caused by loose trundles in the hoop wheel (usually S4). Secure the trundles with a very small amount of Locktite (this is easily done after assembly).


Coat inside the dial and movement screw holes with Elmer’s glue if the screws are loose.

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One comment

  1. Hello i have clock schats jahrfsuhrenfabrick 49 germany not work and i not interesting to fix i buy in garage sale i need sale

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