Tid-Bit 10 - Adjusting Pallets

Published in the June 2011 NAWCC Bulletin, starting on page 330.

The Graham deadbeat escapement is found in a wide variety of clocks, including most of the Vienna Regulators and Precision Regulators seen in my shop. With time the escapements pallet faces become grooved from sliding across the tip of the escape-wheel teeth. Over the centuries this grooving can convert a deadbeat escapement to a recoil escapement. Interestingly, when this happens the clock often continues to run, perhaps a tad fast, but run none the less.
While hardened pallets wear at a slower rate than softer pallets, eventually they all develop grooves, unless of course one is lucky enough to own a clock with jeweled pallets. My methods for dressing grooved pallets are discussed in a previous Technical Tid Bit (see the April 2010 Bulletin, page 191 for Tech Tid-Bit 4).

Figure 2 – Pallet Faces<br />
<br />
As mentioned above, it is possible to develop enough of a groove to lose the locking function completely, converting the deadbeat escapement to a recoil escapement.<br />
<br />
Of course, there are the other situations that develop in mechanisms that have been “fixed” before, for example a mechanism that has a half-deadbeat escapement (incorrect anchor depthing as well as an increased gap between the pallets resulting in recoil on one pallet and deadbeat on the other), or complete lack of lock (runs very fast as a recoil escapement), or perhaps too much lock (doesn’t run at all).<br />
As promised in Tid-Bit 4, this article discusses what to do when there is a need to adjust the degree of lock in a Graham deadbeat escapement. A future Tid-Bit will explain how to make the drop equal on both sides of the anchor.<br />
<br />
It’s about now in these articles that we discuss safety. For the most part the greatest risk one faces in working with an anchor is damage to the anchor. PAY ATTENTION when you get to the part about making sure the arms on the anchor are not hardened, IF YOU TRY TO BEND HARDENED ARMS THEY WILL SNAP. Which brings us to a point about personal safety. When adjusting the pallets on a single piece anchor always wear safety glasses. If something does break you don’t want to have to explain to the nice doctor in the emergency room how a piece of an antique clock mechanism ended up in your eye. <br />
Likewise, if you need to soften the arms so they can be bent – be sure to reread my comments in Tid-Bit 9 on safe practices when annealing metal. The ones that I always remember are:<br />
<br />
Have a fire extinguisher handy<br />
Dry run the process<br />
Have a bowl of water where the anchor will fall if you drop it<br />
Don’t touch hot anchors<br />
<br />
While having read several very detailed discussions of how to design a deadbeat escapement, and thinking I understand the principals involved, the following is based on my experience restoring hundreds of Vienna Regulators. Rather than discussing the technical aspects behind setting drop and lock dimensions for an optimum escapement, I will explain the criteria I use, based on my experience with what works, to set the degree of lock on the deadbeat face and what limits the available degree of lock that can be obtained.<br />
<br />
Before making adjustments to the gap between pallets it is important to make sure that the escapement is in excellent condition. While it is very, very rare that the escape wheel in a Vienna Regulator mechanism has pivots loose enough to cause problems, it is not uncommon to find that the anchor-arbor pivot nearest the crutch is a little loose – which is problematic, especially for miniature Vienna Regulators, with their smaller escape wheels and pallet faces. <br />
<br />
If you think about it, an escape wheel that has some wear in its pivot holes will likely not rock back and forth in its pivot hole as the clock ticks away. Being pressed to one side by the gear driving it, the pivots will likely rest to one side of the worn hole. But, an anchor will move from side to side in its pivot holes, effectively limiting the impulse transferred to pendulum. Bottom line, I do check the pivot hole for the crutch end of the anchor more carefully than any other pivot hole in Vienna mechanisms.<br />
<br />
As a side note, the simplest way to differentiate between Viennese and German-made regulator mechanisms is the design of the anchors. In general, the German, factory made anchors had adjustable pallets while the Viennese used single-piece anchors with fixed pallets. Figure 3 shows an example of each type of anchor.

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Figure 2 – Pallet Faces

As mentioned above, it is possible to develop enough of a groove to lose the locking function completely, converting the deadbeat escapement to a recoil escapement.

Of course, there are the other situations that develop in mechanisms that have been “fixed” before, for example a mechanism that has a half-deadbeat escapement (incorrect anchor depthing as well as an increased gap between the pallets resulting in recoil on one pallet and deadbeat on the other), or complete lack of lock (runs very fast as a recoil escapement), or perhaps too much lock (doesn’t run at all).
As promised in Tid-Bit 4, this article discusses what to do when there is a need to adjust the degree of lock in a Graham deadbeat escapement. A future Tid-Bit will explain how to make the drop equal on both sides of the anchor.

It’s about now in these articles that we discuss safety. For the most part the greatest risk one faces in working with an anchor is damage to the anchor. PAY ATTENTION when you get to the part about making sure the arms on the anchor are not hardened, IF YOU TRY TO BEND HARDENED ARMS THEY WILL SNAP. Which brings us to a point about personal safety. When adjusting the pallets on a single piece anchor always wear safety glasses. If something does break you don’t want to have to explain to the nice doctor in the emergency room how a piece of an antique clock mechanism ended up in your eye.
Likewise, if you need to soften the arms so they can be bent – be sure to reread my comments in Tid-Bit 9 on safe practices when annealing metal. The ones that I always remember are:

Have a fire extinguisher handy
Dry run the process
Have a bowl of water where the anchor will fall if you drop it
Don’t touch hot anchors

While having read several very detailed discussions of how to design a deadbeat escapement, and thinking I understand the principals involved, the following is based on my experience restoring hundreds of Vienna Regulators. Rather than discussing the technical aspects behind setting drop and lock dimensions for an optimum escapement, I will explain the criteria I use, based on my experience with what works, to set the degree of lock on the deadbeat face and what limits the available degree of lock that can be obtained.

Before making adjustments to the gap between pallets it is important to make sure that the escapement is in excellent condition. While it is very, very rare that the escape wheel in a Vienna Regulator mechanism has pivots loose enough to cause problems, it is not uncommon to find that the anchor-arbor pivot nearest the crutch is a little loose – which is problematic, especially for miniature Vienna Regulators, with their smaller escape wheels and pallet faces.

If you think about it, an escape wheel that has some wear in its pivot holes will likely not rock back and forth in its pivot hole as the clock ticks away. Being pressed to one side by the gear driving it, the pivots will likely rest to one side of the worn hole. But, an anchor will move from side to side in its pivot holes, effectively limiting the impulse transferred to pendulum. Bottom line, I do check the pivot hole for the crutch end of the anchor more carefully than any other pivot hole in Vienna mechanisms.

As a side note, the simplest way to differentiate between Viennese and German-made regulator mechanisms is the design of the anchors. In general, the German, factory made anchors had adjustable pallets while the Viennese used single-piece anchors with fixed pallets. Figure 3 shows an example of each type of anchor.

Figure Pallet Faces