First Repair - A Wall Clock

[Nomad]

I'm a beginner in horology whose interest is clock making, but I have elected to try a few repairs as a way of familiarising myself with clock mechanisms - a bit of hands-on experience of ready-made examples can't hurt. So, this thread is about my first attempt to repair a clock, and I'd appreciate any pointers, suggestions, etc, as I go along. Feel free to correct any terms that I get wrong - I come from a mechanical engineering background, but not clocks.

The clock is a wall clock, no chimes, no second hand, no makers marks that I can find anywhere. The dial appears to be cardboard and uses conventional numbers rather than Roman. It has a pendulum and a mainspring. The plates on the movement are about 3" x 2.25". The only mark I can find is on one of the plates: "29 cm". Would that be the pendulum length? (Seems close, but I haven't measured the pendulum assembly yet.)

Below are some photos of the movement, and my thoughts so far.

A general overview...

xyzzytom_210547

This is what I was presented with when I took the hands and dial off. The key came with it, and I found that it doesn't wind - the shaft/arbor inside the mainspring rotates okay, and seems to pull the spring around until it gets to a certain point, where there's a click and the spring relaxes again. The outer end of the spring wraps around one of the pillars and looks intact, so it would seem that the mainspring is either broken in the centre, or perhaps has become detached. There was no ratchet clicking when winding, and it's possible to turn the key both ways.

View of the mainspring, click ratchet thingy, and great wheel...

xyzzytom_210548

Here, you can see the ratchet, the click spring, and a hole to the left of that in one of the great wheel spokes. I had a root around in the case, and found a tiny bit of steel that looks like the end of the pivot for the click. No sign of the click itsel or the rest of the pivot.

My guess is that the pivot for the click has snapped and the mainspring has rapidly unwound itself, possibly leading to damage at the centre. Alternatively, perhaps the mainspring damage occurred first, and the click pivot was a casualty of the released force.

I reckon I can make a new click and pivot, but I don't know yet how the mainspring is/was attached to its arbor (and I haven't attempted to dismantle anything - I'm aware that they are dangerous).


The hour wheel...

xyzzytom_210549

Not in perfect condition. I'm pretty sure I can get that straightened out once it's been removed. Note that the pinion that drives it is sitting quite low below the retaining washer/circlip - a lot of endshake there, but I don't know if it's likely to be a problem.


A general view from the side...

xyzzytom_210550

There are 2 solid pinions and 3 lantern pinions. It's also very dirty. I noticed that the oil in the wells at the pivots is more like a dryish green jelly.


A view from the top, showing the escapement and the bit that holds the spring for the pendulum...

xyzzytom_210551

You can see the hour wheel here as well, and the amount of slack in the pinion that drives it. The escapement seems to work if I hang the pendulum and give it a nudge, and the gears immediately following it seem to turn convincingly. Much muckiness to clean up.

 

[Kevin W.]

Nomad you have your work cut out for you. You have many lessons on this one to learn. Click repair and general repair. A bent wheel too. A few books and some reading might be a good way to start. Most of the power of the main spring has been lessened as you cant wind it.
Ask lots of questions and you will get many veiws and ideas as to what to do for repairs.

 

[Willie X]

You can straighten that folded gear on the hour hand pipe by hand.

It would be best to take the clock apart to address the click.

This is an excellent clock to learn on. Mainsprings can be dangerous, but this particular movement is capable of close to a complete unwind. The plates can be separated without much further movement of the spring. The spring should be partly wound and held in wire when putting the spring back in, but again, in this particular this can be done by hand, you shouldn't need a winder. You can actually use the movement as a winder in this clock.

Winding arbors don't look that worn so maybe its just had a hard time at some point and not worn to badly. Always good to think positive.

Good luck, Willie X

 

[Scottie-TX]

If the click has failed, in all probability the spring has just come unhooked from the tang in the arbor. With a tightly closed loop the spring is secured to the arbor and a tang that ushers it into a tight coil when properly secured. You can go ahead and dismantle it now. No danger at this point altho without a winder, assembly will be difficult with an unwound spring. You need first, a winder and a letdown tool. The hour wheel can easily be straightened. No problem there. From what I read tho you MAY have a cracked pinion or related problem that drives the minute hand. Does the minute hand offer any resistance to being moved?

 

[wow]

Nomad, you actually have a pretty good movement for beginning to learn. First, you must take many photos at every angle and all sides of the movement. You can disassemble it as it is if you secure the mainspring with something like a piece of flexible wire. Just wrap it around the spring and twist the ends until tight. Then when you disassemble it, the spring will not release. Watch closely and take photos as you remove each wheel and mark each one with numbers from largest to smallest (largest #1). Then you must clean each wheel and both plates. Once you get to this point, let us help you with the next steps.

Will
Well you guys beat me to it, but maybe all will help.