Friday, August 22, 2014

" The punchers "

In a previous post I showed how the pivots sometimes wear in clocks.  This isn't that common, but it happens.  In most cases it's the hole in the softer brass plates that wears.  Being spring, or weight powered, the "push" or load on the pivot is only in one direction.  This means the wear in the hole is only on one side, so the hole doesn't get bigger it gets more egg shaped. This plate shows 2 bad ones. You can see how the end of the shaft is off center.
The proper way to repair this is to install a bushing.  It's not that tough.  The hole is brought back to center and then opened up to accept a bushing. These can be purchased in specific sizes so they will be a pressed fit, or made in a jewelers lathe pretty easily.  They can't be soldered because this would soften the brass and it would wear out even sooner.
Now here's the rub.  In order to install a bushing, you need to separate the plates.  Now you have a bench full of gears, and depending on your skill level, or laziness level, some don't want to do it.

Now come the punchers.

" How about if I just smack this brass with a punch to close up this gap ".  Problem is that it works to an extent, but it is short lived because there is not enough surface area against the pivot to last. The biggest isuue is that it permanently ruins and disfigures the clock plate.  I don't care if somebody does it to a cuckoo or modern clock, but having seen it on 19th and even 18th century clocks it breaks your heart.  On some of  these clocks you actually try to make the bushing invisible when you need to install one.  This isn't necessary when doing the more common american clocks where you can just press it in and leave it.

This is a punch job on a 1840's tall case clock movement.  These are permanent scars.

As I said before, all of the wear in the holes in only on one side so the punching is generally only on the wear side.  Whoever got their hands on the 1890's ansonia shown below, really took punching to a real art form.

Here's one more pitiful excuse for a bushing repair.  Take a piece of who knows what, put a hole in it and solder it to the clock plate over the pivot.  As bad as this is, at least it's still reversible.  All of this poor work  is done only because somebody didn't want to pull the clock plates apart.  I've even heard it referred to as "tricks of the trade". 
Well that's a load of crap.  Someone told me one time, "instead of learning tricks of the trade, why not just learn the trade ?"