Mainspring time bomb!

[lmester]

I recently repaired a Gilbert time and strike movement. The clock would run but the hands didn't move. I found that it had a cracked cannon pinion. After making a bushing for the pinion, I cleaned all of the parts finishing with the mainsprings.

The clock has loop end mainsprings. I cleaned and lubed the mainsprings and finished with winding them and replacing the mainspring C clamps. With both springs done & sitting on my workbench I took off my gloves and put the spring winder away. I then picked up the springs and took them over to my work table and set them down.

BOING!!! Instantly one spring was jumping around on the floor and blood was dripping from a nasty cut on my middle finger! One of the clamps came loose. I used a band aid to fix the finger and then checked for clock damage. The spring & wheel were undamaged. I cleaned and lubed the spring again and put the C clamp back on.

This time I jiggled the spring around and tapped it on the workbench a few times BEFORE I removed my gloves.

When possible I make sure that the clamp is centered on the spring. Sometimes it needs to be at one or the other edge because of interference with parts in the movement. In this case it was centered on the spring. I have no idea why it slipped off.

Has anyone else had a mainspring come loose several minutes after it was cleaned and rewound?

I did get a little chuckle from this. With a band aid wrapped tightly around the joint on my middle finger, I was unable to bend the finger very far. So, while assembling the movement, I was also giving it the finger.

 

[leeinv66]

You put a band aid on before you check for damage to the movement? Some might call that being a little precious! Just joking Yes, been there and had that happen with twist wire instead of C clamps. I also had a mainspring shatter while it was sitting on the bench next to me. They certainly can surprise you occasionally!

 

[MartinM]

I had one break in the winder and it works better than a pot of coffee to wake you up.

 

[harold bain]

I had an Ingraham movement sitting on a shelf, and just as I walked by, the mainspring broke, and the movement launched itself at my head. My reflexes must have been really sharp that day, as I caught the movement, no damage done.

 

[Randy Beckett]

I had an Ingraham movement sitting on a shelf, and just as I walked by, the mainspring broke, and the movement launched itself at my head. My reflexes must have been really sharp that day, as I caught the movement, no damage done.

More evidence that evil, restless spirits from the past do sometimes take up residence in these old clocks.

 

[harold bain]

More evidence that evil, restless spirits from the past do sometimes take up residence in these old clocks.

I think you are right, Randy. The movement had been on that shelf for a couple of weeks, waiting for me to install it in a customers clock that I was restoring (another repairman had quartzed it, so I bought a loose movement to return it to a mechanical clock). I probably walked by it 3-4 times a day, and it picked exactly the right time to break as I walked by.
It needed to come apart for cleaning and some bushing work anyway, and I'm pretty sure I also replaced the other spring when I overhauled it.

 

[doug sinclair]

Years ago, I decided that it was time to replace the mainsprings in a mission style time and strike wall clock. It had run down and stopped. I pulled the movement from the case, and lo and behold, what did I see? One of the run down springs had cracked clean across............except for a bit of spring about .50 of a mm wide at one edge! Had I not decided to do the springs at that time and instead had decided to wind it, BANG! That spring would have broken the rest of the way the moment I turned the key!

 

[R. Croswell]

More evidence that evil, restless spirits from the past do sometimes take up residence in these old clocks.

No doubt about it in my mind!

I almost never use the clamps for three reasons: 1) the hold the spring tighter than I like for reassembly, 2) there is often not enough room to use them, and 3) I can't easily slip them off without going back to the spring winder. With wire I just snip the wire. Never had wire bust but if its a real bull of a spring I sometimes use two wraps (one piece of wire).

RC

 

[BigAl]

Out of curiosity, what sort of wire do you use?

BigAl

 

[R. Croswell]

Out of curiosity, what sort of wire do you use?

BigAl

I believe it is 18 gauge soft steel. In US it is sold by Lowe's (a large home and building supply store) in the section with the stuff for hanging suspended ceilings. It is also available in heavier sizes but taking two wraps makes it twice as strong but 1 wrap is usually enough.

http://www.lowes.com/pd_12841-1463-5010___?productId=3199005&pl=1&Ntt=suspended+ceiling+wire

or this heavy stuff if you are afraid of the 18# stuff
http://www.lowes.com/pd_51214-1463-6012___?productId=3199513&pl=1&Ntt=suspended+ceiling+wire

 

[doug sinclair]

One wrap or two wraps, would the wire not be weakest at the "twist"? Just wondering.

 

[David S]

Doug I think so if you "over twist". I gave up on the c clamps and always use wire now. I just pull the double loop of wire tight and then twist until it looks snug.

David

 

[dAz57]

I just use 3mm braided nylon cord, use a square or reef knot, the cord is reusable over and over, never had one come loose.

 

[R. Croswell]

One wrap or two wraps, would the wire not be weakest at the "twist"? Just wondering.

I'm sure it is. As suggested, don't over twist.

RC

 

[ClipClock]

I had an Ingraham movement sitting on a shelf, and just as I walked by, the mainspring broke, and the movement launched itself at my head. My reflexes must have been really sharp that day, as I caught the movement, no damage done.

That did make me laugh, but well done for catching it!

My old spring winder used to regularly unleash springs at maximum wind, it certainly added adrenaline to the whole process. I used to dress like Michellin Woman when it was time to 'do the springs'. It got less fun when I started tackling big old chimers so in the end I chucked it away and got another, I couldn't in all conscience sell it