Loaded the mainspring by hand after a bit of de-coning - these big springs do make me nervous so safety glasses, thick gloves covered with large plastic gloves and most importantly a many folded thick towel in the lap - I know which part of me I'm most concerned about
馃槈
With the mainspring in, used the blower on the escape wheel and all ran freely so, time to fit the pallet and other parts. Here are the parts that make up the assembly.
All these parts have special clock names.... Anyway, the double hook shaped thing is the pallet and mounts on the shaft and is secured by a screw. The shaft pivot at the dial side mounts in a hole in the plate but the rear side mounts in the lower left piece which attaches to the rear plate with two screws in slotted holes for adjustment.
Well, am not sure what sort of escapement I have - I thought it was a half deadbeat but it's unusual for the escape wheel teeth to slope away from the direction of rotation. Here the entry pallet is coming up to a tooth.
The wheel is rotating anti clockwise here and only the outside curved part of the fork will work. It slides down to lock and when the pendulum swings it rocks back up and the wheel gives an impulse to the end of the fork to give energy to the pendulum. As it rocks over, the exit pallet comes on to a tooth further around but, this is the same face again (the leading face of the tooth.
As shown, it's locked but this side doesn't give an impulse to the pendulum hence the "half" deadbeat. Still think the teeth should slope in the opposite direction but, it works so, it is probably a variation on half deadbeat.
Assembled the parts - the pendulum hooks into the lower slot of the upper piece. The slot above takes the cranked arm from the lower piece which is clamped to the pallet shaft.
Put the pallet in earlier this week and it hardly ran as it had low amplitude (pendulum swing) and stopped after 18 hours. Fiddled with it and eventually went back to first principles and loosened everything off. Set the drops to be equal and eventually got it in beat and was still running after 48 hours from half wind with much better amplitude.
馃榾 It's a 1.44 Hz, 10368 A/H movement (by counting the wheel teeth) which seems a bit of an odd number but, what do I know. You adjust the rate by changing the effective length of the pendulum and here it is timed after 48 hours on my phone.
The blue is a 5 second average, the green 20, I think and the red is 60 seconds. It's clear there is some variation but, you don't time these like this. Better to let them run for a week as that averages out the variation. On that note, I have another Smiths, in my car, which I rebuilt
here and after two months running, it's averaging 3 seconds loss per day. Really pleased with that!
馃榾
Next is to let it run for a week to test the power reserve, which should be 8 days. Have mounted the hour gear and pipe so I could put the hands on. Will find out in a week and then add the chimes etc.
Cheers, Chris