My ST124 Project

[Jrfixer]

Well I must say this has been a challenge. I got this clock at a ham radio flea market for $10 with the winding key and bob. After inspection it seemed no one had touched it, which is a good thing. It is dated July 1948. After cleaning and oiling it seemed to work. However, that was short lived. I finally disassembled it and gave it a good cleaning. It seemed this clock had not many hours of use. T2 pivots had a bit of wear but not really that bad. All the other pivots where in great shape. After reassembly it worked for 2 days then stopped. After a few more attempts to get it going with out luck I decided the main spring must be bad. So the new main spring is installed, which was a challenge too, as the boxes are riveted to the plate. The old time spring(on the right) does not look like the new one (on the left). I wonder if this was factory installed? Here are a few pictures.

 

[ChimeTime]

One of my first project clocks was also a tambour. Your photos brought back the delight of that experience. You're doing great. Keep it up and keep us posted.

 

[Kevin W.]

I rarely change main springs, if a customers asks me too, i would. Many or most that are original to the clock are better than whats out there today. Great clock and movement, i have one, which will be a good one to learn chime repairs on, glad you serviced it.

 

[Jrfixer]

I'm with you Kevin. I was second guessing changing the main spring too. The old one appeared to be in good shape. I'm just a bit surprised at the difference between the new and old one. It appears to be somewhat longer the the new one, which was ordered from Timekeepers as the stock size for the 124. So far she is tik-toking like a champ. Fingers crossed.

 

[Jrfixer]

Update - Good news so far (about 20hrs). The movement is humming along keeping good time with out any stops. Chime and strike are working perfectly thanks to Steven Conover's book! I just checked the beat with the iPhone Clockmaster app and the results were good. Delta is between 1.5 to 9 (before the mainspring change it was 6 to 15 ish) with an average BPH around 10578 to 10586. My biggest problem so far is getting the wife and dogs to be quite while checking vitals

 

[Kevin W.]

Good work Jrfixer.

 

[Jrfixer]

Thanks Kevin. Truth be told I'm only getting away with this as long as I can keep SWMBO happy with a new carbon steel wok, blued and seasoned. And setting up the smoker for some yummy food. Today was a good day!

 

[Jrfixer]

Update - 2 weeks running without any stops. The No.124 is playing nicely with the No.89 in the same room.

I must say the tic-toc of the 89 (9777.86 bph) to the 124 (10584 bph) is a bit weird at times .

That said, when they strike and chime together, it is truly amazing!

 

[Dave T]

Interesting approach you used to change that mainspring. I wasn't smart enough to figure that out when I worked on mine!

 

[Jrfixer]

I must admit, it was a bit easier than I was expecting. Making the arbor was a bit of a challenge. The hardest part is getting the barb shape on the first try. I used a .100" drill bit, and tapped to 4-40.

The length of the arbor is directly related to the head distance of your winder. Make it just long enough to get the spring on/off. Drilling the hole all the way through the tail stock so the arbor can go all the way through so the spring can sit flat against the stop.

Screw the box assembly to a board, and release or make some potential energy

Stay safe, wear gloves and eye protection.

 

[Jrfixer]

Let’s just say YouTube is quite challenging to setup.

 

[Jrfixer]

So my ST124 stopped a few days ago (no stops in the past 8 months)… I must have forgot to wind it…? Nope, it stopped again a few hours later. I pulled the movement for inspection and found everything to be good. Upon running on the bench I did notice the bob would begin to wobble/oscillate after a minute or so. Why this started to happen now? It is a bit more humid and warmer then the past 8 months.…?

After some troubleshooting I found that tweaking the bob wire a bit, so that the bob was not parallel to the movement by a degree or 2 it would run without oscillation. I’ve attached a link to a video of the before to show the wobble. It doesn’t seem like much but it made a difference to the proper operation.

So far it’s been running fine.

 

[R. Croswell]

Don’t see any video. You should not need to hang the bob at an odd angle. The wobble is usually because something is trying to move the pendulum in a different direction than it would naturally swing. Make sure the suspension spring is in line with the leader, the crutch, and d the Bob. The 124 likes to be near perfect to be reliable. As I recall these used several varieties of deadbeat escapements. make sure the escape wheel teeth land on the dead face and not the impulse face.

RC

 

[Jrfixer]

Well RC, you sir are right. The clock stopped a 4am this morning so something is still a miss. I readjusted the crutch to be more inline with the suspension spring. It is running good at the moment, time will tell

My other thought is that there is friction building up some where in the time train. So I inspected the pivots under the microscope. Everything still looks good. I mopped up some excess oil and added some CFD-703 I had from my past days of repairing CD players. This was used on the sled rails to keep the laser assembly moving smooth to avoid skipping. Amazing stuff.

 

[wow]

In 124s the time train is not very forgiving. Every pivot must be snug and straight. You said you inspected with magnification. May I suggest that, if you did not, let down the power on the time train and begin rocking each wheel beginning with the mainspring wheel (T-1). While rocking, watch the pivots of the next wheel (T-2) for sloppiness. Move up the train rocking each wheel until you reach the escape wheel. If there is sloppiness, mark the d direction of the wear. If you do this you will either find or eliminate the source of any power problem. If any are very sloppy, they must be bushed.

 

[R. Croswell]

Well RC, you sir are right. The clock stopped a 4am this morning so something is still a miss. I readjusted the crutch to be more inline with the suspension spring. It is running good at the moment, time will tell

Did that fix the wobble?

A pendulum wobble will rob a small amount of power.

One indication of how well the clock is running is how much overswing it has. That is, when the clock "ticks", how much further does the pendulum continue to swing in the same direction before swinging back in the opposite direction. Zero overswing and the clock will be very unstable and likely stop frequently.

This clock has a deadbeat escapement. If it is adjusted properly, when the clock "ticks" the escape wheel should stop dead until it moved ahead on the next tick. If you see the escape wheel back up just a bit between ticks (recoil) it is not adjusted correctly and is wasting power. Best to evaluate this by operating the pendulum by hand.

Everything WOW said, and this includes the pivots that support the verge. If you see the verge pivots dancing around in the hole when it is running then you have a problem.

The video plays OK on my PC. A video showing the action at the escape wheel might be helpful.

RC

 

[Jrfixer]

So far so good. She is running great. Here is a little video of the ClockMaster data in real time. The beat rate target for this movement is 10584 B/H

 

[Willie X]

"Project" is a good word for an ST-124.

The ST-124 is one of the few clocks that I don't take in for repair. They are the king of comebacks and I do not like comebacks. Willie X

 

[Jrfixer]

"Project" is a good word for an ST-124.

The ST-124 is one of the few clocks that I don't take in for repair. They are the king of comebacks and I do not like comebacks. Willie X

Now you tell me

It is my only Westminster chime, so it is missed when it’s not working. That said it has run solid for 8 months before a misfire.

Fingers crossed.

 

[Bruce Alexander]

Make sure that the chops are tight against the suspension spring and that the chops assembly doesn't have enough slop to allow it to swing with the pendulum. Those conditions can lead to pendulum wobble and can easily rob enough power to cause intermittent stalling.

 

[wow]

"Project" is a good word for an ST-124.

The ST-124 is one of the few clocks that I don't take in for repair. They are the king of comebacks and I do not like comebacks. Willie X

I don’t like them either. I have three in my shop now. I spent most of today tearing one down for the third time and adding three more bushings I had missed last time. It’s up and running great as of now. The escape wheel pivot on the opposite end of the wheel was sloppy and the T-2 and T-4 each had a loose pivot. We’ll see tomorrow. I’ve done so many lately I have developed a “method”. It does get better, JR.

 

[Willie X]

I've repaired a lot of em but I would guess that maybe half of the owners were happy in the long run. Willie X

 

[R. Croswell]

I think their reputation is well deserved, but I really don't know why. They are a bit of a pain to work on, but I can't put my finger on any one design flaw that should cause them to be so cranky. When I see one come in, I think, well it could have been a Welch, Spring & Co. Patti movement, or a Waterbury triple plate chime movement and then the 124 doesn't seem, so bad after all.

RCV

 

[Jrfixer]

Well here is an update for those interested. 48 hours without any stops. Keeping good time too.

I’m going to guess that I have friction in the time train that is/was the root of the problem. The magic CFD-703 seems to have solved it for now. Let’s see how long it lasts.