Bent and scraped

In our last episode your horological historian got a bit strung out (sorry) on banjos.

It is a truism in the horological world that simply oiling an unknown movement (even if it looks superficially like it is in good shape) is really not sufficient. Only a full disassembly and inspection can reveal many types of problems. 

The Sessions York appealed to your local horologist with a host of fine features however, unsurprisingly, there were a few issues needing remedy as well. 

Discussed in an earlier episode was our bent escape wheel tooth.

Our York had two other problems that were revealed after disassembly. 

Firstly... well... look.

Did this bend of the wheel occur during that same (possible) bump that affected the escape wheel tooth?

Maybe.

Fortunately this repair involves just gentle bending with flat-faced pliers (a clockmakers workhorse).

The next issue was trickier.

Virtually all American clocks were made with a strip-styled pallet in the escapement. Basically a bent piece of steel. They are cheap to make and relatively easy to replace (if necessary) but not as robust as other forms of anchors. An earlier example comparing them can be found here. 

The regular reader might recall examples where this Clock Fool droned on about explained the parts and action of the pallets on the anchor of a clocks escapement. 

The faces of the pallets can become worn by the endless collision of the escape wheel against them. The escape wheel teeth push the pallet. That's what drives the pendulum.

See again the gif showing the action of the escape wheel teeth hitting the pallets of the anchor on the movement of this York. 

See how the teeth hit and then slide off the face of those pallets?

That sliding action creates considerable friction and over decades can create grooves in the pallet faces.

We've seen this same problem before.

However the grooves on this Yorkie's pallet faces are deep. Take a look at the face of the entrance pallet.

Not good.

The teeth of the escape wheel are actually cutting through the edge of the pallet face. Both pallet faces are deeply pitted with grooves.

What to do?

Option 1: replace the anchor entirely. Probably overkill.

Option 2: grind and resurface both pallet faces and then bend the newly (slightly) flattened faces back to exact original angle of the original face. Real clock guys do this sometimes. It's a lot of work.

Option 3: weld a tiny bit of metal in the groove. Flatten, smooth and polish. Messy and easy to screw up.

Option 4: nudge the pallet over a bit.

What's that Doctor Clock?

Given that this goober blogger spent so much time creating graphics on another clock that show the parts needing explaining, a straight copy-paste of some images of that clock's escapement will be utilized.

The following photos are from A DIFFERENT CLOCK that has a very similarly designed escapement as our Yorkie.

All of these steel strip anchors pivot back and forth on their saddles, a brass strip, riveted to the anchor and bent down into a leg on either side which are perforated to allow it to slip over and ride on a pin/pivot. A bit like a seesaw.

Here's an anchor and its saddle (from the earlier clock). Very similar to the Yorkie.

And here is the anchor installed in that clock's movement. The anchors saddle rides on its pivot and is held in place by the keeper. It had some wear too.

 

Here's a shot of the pin/pivot that its anchor saddle rides on.

See how the pin/pivot sticks out like that? The two legs of the saddle slide over that through their pivot holes and the whole thing is held in place by the anchor keeper.

If one were to put say a small washer, perhaps just a bit over 1mm thick, on that pivot and then slide the saddle on as usual...

The whole saddle / pallet would now be pushed out just a bit along that pivot by just over 1mm. It would still ride the pivot but just be seated a little over 1mm further out from the movement. 

So... the anchor is now riding further out along its pivot, a distance that is just a bit greater the width of a tooth of the escape wheel, which stays exactly in its original place. The net result is that the escape wheel teeth will now hit a different part of the pallet faces. A part that is just over 1mm to the left of the original points (deep grooves) of contact on the pallet faces which have now effectively been seated 1mm to the right because of that washer.

Hopefully this image helps to explain (and we are now BACK to photos of the Yorkie).

Et voila, the escape wheel teeth will now hit unworn / previously untouched metal.

OK it took a bit of finagling of that saddle but...

It worked. And of course credit for the idea is due to the NAWCC boys.

That fix will probably last another 100 years.

Movement reassembled and tested. 

Runs like a champ.

YLH cleaned up the dial a bit with Gojo cleaner. Ditto the hands.

Case given a light clean, a quick coat of Howard's Restor-A-Finish and then some Feed-N-Wax.

Movement installed in the case.

Up on the kitchen wall.

She looks rather smart. And is keeping pretty good time.