Fusee Clock keeping poor time

[rodabod]

39 minutes ago, 4ster said:

Sure looks like the cone does not match and equalize the properties of the spring

Yes. I would have a look at the spring. Rather than assume the spring is incorrect, I would check to see if the spring is very "set".

I think I'm possibly correct in saying that according to Hooke's law, you may actually get relatively more torque at the start of winding when the spring is set due to the angle of rotation, but I've never measured this myself.

[nickelsilver]

Also, if the spring is too strong it may be too short and nearing or at the end of wind when fully wound. Even with the fusee it may be giving too much power, which with a recoil escapement can actually drop the amplitude due to strong friction during recoil. My gut says slightly weaker spring and slightly lighter pendulum, I do a number of clocks in this pendulum length and 150g is average, springs maybe 0.25 or 0.3 thick, no fusee and they keep time well. Recoil escapement.

There's a lot at play, a well proportioned recoil escapement can give a deadbeat a run for its money on precision. I go with OH's gut feeling that the escapement is dry and possible spring issue. My first step would be get a bunch of Moebius 8300 on those escape teeth and note the difference. Check palettes (again Old Hippy). They should be smooth and polished. If that doesn't help pull it all apart and check the spring. You want generally 3/4 to 1 turn pretension, and have a reserve of 1 wind when the fusee stop piece comes in.

[4ster]

Thanks everyone for the sage advise. I'll give it a clean and polish and see how it goes, may just take a peep at the spring while its appart.

Will post progress

Thank you all once again,

Pete

[wls1971]

1 hour ago, nickelsilver said:

My gut says slightly weaker spring and slightly lighter pendulum, I do a number of clocks in this pendulum length and 150g is average

I don't think these clocks where designed to use a light weight pendulum the eight day fusee timepiece movements used a standardised pendulum and bob which is heavy at 250 to 260 grams. Williamsons aim in production was to have completely interchangeable parts between clocks which they achieved at the Salisbury factory before it burnt down.

[rodabod]

Another thing you can do why the movement is out of the case is inspect how much torque is getting through the train of wheels at different states of wind - have a feel at how much force there is turning the escape wheel while the pallets are removed. This may give you a better idea about the state of the spring, or if as suggested by others, if escapement friction is upsetting things.

[nickelsilver]

I don't think these clocks where designed to use a light weight pendulum the eight day fusee timepiece movements used a standardised pendulum and bob which is heavy at 250 to 260 grams. Williamsons aim in production was to have completely interchangeable parts between clocks which they achieved at the Salisbury factory before it burnt down.

Yeah I was reading about that (the interchangeability), figured the pendulum weight was maybe slightly heavier on a fusee. The clocks I see here with a similar pendulum/escapement are typically "neuchateloise" with either thin springs making 14ish turns of wind with a well engineered outer hook (very even power delivery) or similar with a close to deadbeat escapement and good hook- bridles, not holes, and a more typical 6 turns of wind.

My gut feeling is too strong mainspring (short) and possibly dry and/or damaged pallets.

[oldhippy]

If you decide to take out the mainspring you should use a mainspring winder, the same when you have cleaned it or replaced it. Always wear gloves to protect your hands.