Gilbert clock won't stay running

[heifetz17]

Hi guys, I'm fairly new to clock repair so I'm a little stumped right now. I picked up an old Gilbert mantle clock that wouldn't run, took it apart, ultra sonic cleaned it, oiled, reassembled, and it's been running fine for a week. Today out of the blue it stopped. Thinking it just needed to be wound, I wound it, but it will only run for several seconds and stop.

It's in beat and very even, the hands are not touching, and pendulum is not touching anything, there's no interference that I can see. Where can I begin my troubleshooting?

 

[Clocks In The Grove]

H-17 did you put in any bushings? Are any of the pivot holes in your mantel clock oblong? If so then your train is being robbed of power. Did you lube the main springs? My guess is a loss of power caused by wear. Remove the power and push back and forth on the second wheel and look for pivots moving in their holes. If you see then flopping then I think you have found your problem.
It is now time to sign off and go to bed for me.
..Bob..

 

[heifetz17]

Ah, thank you Bob! It seems you hit the nail on the head. I did find some slight movement in two of the pivot holes, so I'll install some bushings and go from there. Thank you!

 

[R. Croswell]

It isn't likely that worn pivot holes or lack of lubrication is the cause of a clock that was running to suddenly stop. Gilbert clocks are notorious for developing cracked cannon pinions (a small brass gear on the center shaft). Some times this can cause the motion works to lock. That's where I would start looking.
RC

 

[Willie X]

I'm with RC. Check for end play on the hand shaft, if there is no endplay this little gear is cracked. This problem usually has a second symptom of a loose minute hand clutch. Here's a photo of the culprit. Willie X

 

[heifetz17]

Thanks guys. I'll have a look at that while I have it apart again. The only thing I've noticed weird about the hands is the hour hand does not rotate with the minute hand when I manually rotate it such as setting the time. I have to adjust the minute hand then adjust the hour hand. But the hands move together properly while the clock is ruining.

 

[R. Croswell]

Thanks guys. I'll have a look at that while I have it apart again. The only thing I've noticed weird about the hands is the hour hand does not rotate with the minute hand when I manually rotate it such as setting the time. I have to adjust the minute hand then adjust the hour hand. But the hands move together properly while the clock is ruining.

That's a good indication that the cannon pinion IS cracked and slipping and/or something is out of order in the "motion works" (the cannon pinion on the center shaft, the small intermediate gear it drives, and the pinion that turns the gear on the hour hand pipe).

RC

 

[heifetz17]

I’m finally getting around to working on this and I’ve replaced several bushings and as suggested the cannon pinion is indeed cracked. I can’t seem to find the correct one on timesavers. Does anyone have a recommendation on where I could find a a replacement?

 

[JTD]

I’m finally getting around to working on this and I’ve replaced several bushings and as suggested the cannon pinion is indeed cracked. I can’t seem to find the correct one on timesavers. Does anyone have a recommendation on where I could find a a replacement?

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I can't help you with finding a replacement cannon pinion (I'm not even in the right country!) but just wanted to thank you for posting beautifully clear pictures of the cracked part. I have often read of this problem occurring but until now never seen it clearly. Now I know. Many thanks.

JTD

 

[R. Croswell]

I’m finally getting around to working on this and I’ve replaced several bushings and as suggested the cannon pinion is indeed cracked. I can’t seem to find the correct one on timesavers. Does anyone have a recommendation on where I could find a a replacement?

View attachment 557995 View attachment 557996 View attachment 557997

Timesavers sells this part (No. 20805) as replacement for the Gilbert pinion; Timesavers Folks here have reported that you may need to slightly open the hole a bit to achieve the proper pressed fit. If you search for cannon pinion repair you should find a number of discussions of various methods that have been used to repair that broken pinion.

RC

 

[heifetz17]

Timesavers sells this part (No. 20805) as replacement for the Gilbert pinion; Timesavers Folks here have reported that you may need to slightly open the hole a bit to achieve the proper pressed fit. If you search for cannon pinion repair you should find a number of discussions of various methods that have been used to repair that broken pinion.

RC

Thank you. Is it supposed to be pressed on? Right now it just slides on and off the shaft easily, but I suppose that may be because it’s split open.

 

[R. Croswell]

Thank you. Is it supposed to be pressed on? Right now it just slides on and off the shaft easily, but I suppose that may be because it’s split open.

Yes, pinion "A" is pressed on to partly compress spring "B" to form a slip clutch that drives the hands but slips to allow the time to be set. The press fit has to be tight enough to hold the spring partly compressed. Fit it too tight and the new pinion will bust just like the old one.

Some have had success soldering the old pinion directly to the shaft. If that is attempted, there are several requirements: the old pinion must be relieved and the crack closed, it must be soldered in the exact right position, you will need to back off the spring during soldering and then reposition it for tension. The old pinion can be reamed out and a bushing soldered in and the bushing sized for a press fit.

RC

 

[shutterbug]

I would go with the new one, and yes - it needs to be reamed a bit so it goes on hard but not so hard that it will crack again. You can put it on with a hollow punch and hammer if you don't have a press. Be sure to keep everything nice and straight so you don't bend the arbor, ... and protect the other end.

 

[heifetz17]

Thanks guys! I’ll replace the pinion and report back!

 

[heifetz17]

So I’m at a loss with this clock. The canon pinion finally came in off back order and I replaced it but the clock still will not stay running. I pressed it onto the arbor just enough to give the spring enough pressure that the gears hold together, so not too tight. I’ve replaced several bushings as well.

When I remove the springs both trains spin freely within the plates with no binding whatsoever. The clock will run for an hour or two and then stop. Does anyone see any obvious issues that I may be overlooking?

 

[shutterbug]

I'm wondering about the verge. Can we have a good look at that?

 

[Kevin W.]

Do you have a healthy swing of the pendulum?

 

[heifetz17]

I'm wondering about the verge. Can we have a good look at that?

Yes I was wondering about that as well. When I was watching the movement yesterday something seemed off about the verge. I'll post a close up tonight when I get home.

Kevin: Yes, the pendulum seems to swing well and even.

 

[R. Croswell]

When it stops, if you move the pendulum does it start up for another hour or two without doing anything else to it?

RC

 

[heifetz17]

When it stops, if you move the pendulum does it start up for another hour or two without doing anything else to it?

RC

Yes, it's hard for me to tell but I'm starting to think maybe something is catching or binding in the verge/escapement. But to answer your question directly, yes.

 

[Kevin W.]

What about slightly raising the verge. I had a similar problem and this did make the clock run.

 

[heifetz17]

Yes perhaps that would work. I’ll post a couple pictures tonight before I make any adjustments to it.

 

[heifetz17]

As requested. Please let me know what you guys think. Thank you!

 

[R. Croswell]

It looks like there is very little clearance at the entrance pallet. With the pendulum removed slowly move the crutch back and forth and watch each tooth as it passes the entrance and exit pallet. A slightly bent tooth tip could be the issue. Looks like bushing work at the escape wheel pivot. Could be a shadow but if this bushing is badly worn you won't be able to adjust the escapement. Put a tooth pick or similar in the wheel (gear) before the escape wheel so there is zero power at the EW, the lay the movement on its back and use a probe to lift the escape wheel up to the top plate and release it. There should be a little end-play or end-shake in that arbor and when you release it it should drop quickly under its own weight. Repeat with the movement face down.

RC

Also make sure the two "dog bones" that support the verge are set so the verge arbor is 90 degrees to the plates. If one bone is ahead of the other it can pinch the pivots.

 

[heifetz17]

I did as you instructed. The escape wheel seems to move freely through the pallet all the way around, but as you observed there’s very little clearance. Maybe 1 or 2 thousands of an inch on both the entrance and exit. That is indeed an old bushing but it doesn’t appear to be worn. Your second test showed just a little end play and the wheel fell freely under its own weight with the movement on its front and back. I also verified that the verge arbor is exactly 90 degrees to the plates.

 

[Willie X]

Before doing anything to the escapement let's go back to the minute hand shaft.
The correct position for the little gear is the position that gives you about .010 to .015" end play when assembled. The train will still spin freely with a negative end shake between the plate and the hour tube gear. But it won't run correctely until you have the just mentioned positive endshake. The endshake can easily be adjusted by simple measurement as in the photo. This one had 1.375" between the plates so it needs 1.365" at the position shown. Willie X
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[heifetz17]

Thank you! I’ll take the movement back apart tomorrow and double check my gear placement.

 

[tracerjack]

First time I repaired a cracked pinion on a Gilbert, I was slightly off so that when I hand held the plates together the center arbor spun freely, but once the plates were tightened with the nuts, it pinched.

 

[R. Croswell]

Thank you! I’ll take the movement back apart tomorrow and double check my gear placement.

If what Willie described checks out, and you have it apart, you might assemble just the time side and leave out the center shaft and motion works and see if it will run.

RC

 

[heifetz17]

Thanks guys! I’ll try those things and report back!

 

[shutterbug]

A couple of your pictures show the exit pallet bottoming out against the rim. Is it doing that while it's running? Raising that verge just a little might make a big difference. That's an awkward one to adjust. Just a little front and back.

 

[heifetz17]

I think Willie may have hit the nail on the head! My movement also has 1.375” between the plates but the hour wheel and arbor measured at 1.385”. I pressed the cannon pinion on another .020”, raised the verge just slightly and verified that the train spins freely without the motion works. This time when I reassembled everything the escapement started up as soon as I wound the spring and I didn’t have to start it manually! I’ll let it run tonight and make sure it’s still running in the morning! This is/was an awesome learning experience for me!

You guys are all awesome! Thanks a million!