Thursday, February 28, 2013

Longcase - Small Repairs

A lot of the repairs that are needed on this particular clock are simple (and not-so-simple) solder repairs. Some a tricky, some could potentially be a complete nightmare, but so far, so good.

Let's start with the pendulum rod and rating assembly. This was one of the first things I tackled.

You may remember that it looked like this:

There are two repairs needed here. The broken rod (with the broken tip in the top of the rating assembly), and the severely bent threaded rod.

What most people would be tempted to do is to grab a pair (or two pairs) of pliers, and attempt to straighten the threaded rod. This could work, but it could also cause several problems. In the "best case scenario" this works fine, and the rod is once again functional. However, in the "worst case scenario" you could end up snapping the rod, or crushing/marring the threads. On items this old, it's always better to tread carefully.

I chose to heat the threaded rod with a torch until the steel was soft, and then simply bend it as best as I could, using the hole in my anvil as a leverage point. This left me with a very safe repair that insured the safety of the threads, and applied very little stress on the rod. The result is not a perfectly straight "good as new" repair, but the nut moves easily from top to bottom.

For the top of the assembly, I was lucky to find that a small portion of the threaded tip was still protruding, and it came out with almost no force. I chose to use hard solder (high heat silver solder) for this repair, since it will need to handle a fair amount of stress.

Another repair option would be to re-thread the end of the rod (since only 3/16" was broken off), but it's been my experience that the threading on these is almost always "non standard". In fact, I was going to flip the rod to have the soldered repair at the top, but the threading on the suspension spring block is not the same size. Silver soldering can be tricky to learn, but it is essentially the same as regular soldering. The only differences are that you need a special solder (I believe mine is borax based) and you need to be sure that both parts being jointed together are RED HOT. If the parts are not hot enough, the solder will not flow.

One of the drawbacks of high temperature solder is that on most items, you will completely discolour the metal(s) being fused. You will also want to make a very neat repair, since the cooled solder will need to be ground or filed off.

Here is the finished repair (sorry the camera was not quite in focus).

Another quick and easy repair was the bell stand. I was able to bend the break back 95% without having it snap off, and then I soldered the break with silver solder.

Here you can see the soldered joint before clean-up. You can see how darkened and discoloured the steel is, and the silvery-gold colour of the silver solder.

Once cleaned-up, the repair (especially in a crevice like this) is nearly invisible.

Another simple repair was fixing the light bend(s) in the crank key. The key is VERY sturdy, but I was able to bend the key with just hand pressure. This "repair" isn't that much of a repair, but it does make a noticeable difference.

The last little repair (so far) was this screw. This is one of the two screws holding the bridge piece for the hands (which is also broken, and will be discussed later). It appears to have been in use "as-is", but I wanted to try to repair it.

I have NO IDEA how someone managed to split a screw in a partial spiral down the centre, but I suspect it may have been an original defect in the steel.

I used regular (soft) solder for this repair.

You can still see the split, but I didn't want to use too much solder. The head of the screw was also repaired. When I see badly mangled screws, I usually take a few minutes to file-off the marks around the slot, and improve their look as much as possible.

The next post will cover the repairs to the clock hands.

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