Making your own clock jewel

This article was published in the December 2000 NAWCC Bulletin, starting on page 794 Hockey Pucks in Old French Clocks (How to drill an agate and create your very own clock jewel...) Recently I had the opportunity to work on a French clock that was a bit different from the round “Paris” mechanisms I usually see. As I took the mechanism apart, I found a number of clues that told me the mechanism was special. It had (or was supposed to have); silk-thread suspension, every screw, except for those that were obviously replacements, was ornate, with grooves cut around the heads and the classic V-shaped screw slots, and the two strike-mechanism arbors were both rather ornately worked. Then I found the most interesting point, and the reason for this article. While both of the escape-wheel pivots had been replaced, and rather poorly at that, one of the pivots rotated in a jewel set in a threaded brass plug. The pivot at the jeweled end of the arbor was appropriate in that it measured roughly thirteen thousandths of an inch in diameter. The other pivot, which rotated in a hole cut in a similar brass plug, was roughly fifty thousandths in diameter and not centered on the arbor. One plug had a jewel in it. The other didn’t. To follow this through to the end, click on each picture for a description, and further details on drilling a clock jewel.

Putting on my thinking cap, I quickly guessed that someone probably did not insert the jewel into the original brass plug, instead someone probably replaced the other jewel at some point when it was broken. Of course this is just a theory. Perhaps there was a rather bored jeweler somewhere that decided that he or she would just see if they could jewel just one of the pivots, thinking that they would really surprise some future clock-maker. But probably not. <br />
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Now, while I have called the jewel a jewel, perhaps I should be more specific. The little shiny thing in the middle of the end of the brass plug, with the really little hole in it, was not red, not blue, not clear, and not broken. It was agate, at least that was the conclusion from several rock-hounds that I talked to. So, for clarity’s sake, I will call it an agate from now on. Please don’t confuse this with the marbles you may have had when you were a kid. THIS AGATE IS A WHOLE BUNCH LITTLER, and then there is that hole in the middle...<br />
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Now, the easy, and sensible thing to do at this point would have been to fit a friction jewel (like the ones used in watches) in the brass plug, and call it good. This would have taken a half hour, but then the jewels wouldn’t have matched. And besides, then I wouldn’t have had a reason to write this article about agates! <br />
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So, the easy first step was to get a slab of agate. My local rock shop came up with one, but kept looking at me sort of funny when I told them that I wanted to make a jewel out of it. That’s ok, he only charged me forty-five cents. Note, that is the least expensive part of this effort, and that is what the agate is made from. I also bought carborundum in four grits, 80, 200, 1000, and 1600.

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Putting on my thinking cap, I quickly guessed that someone probably did not insert the jewel into the original brass plug, instead someone probably replaced the other jewel at some point when it was broken. Of course this is just a theory. Perhaps there was a rather bored jeweler somewhere that decided that he or she would just see if they could jewel just one of the pivots, thinking that they would really surprise some future clock-maker. But probably not.

Now, while I have called the jewel a jewel, perhaps I should be more specific. The little shiny thing in the middle of the end of the brass plug, with the really little hole in it, was not red, not blue, not clear, and not broken. It was agate, at least that was the conclusion from several rock-hounds that I talked to. So, for clarity’s sake, I will call it an agate from now on. Please don’t confuse this with the marbles you may have had when you were a kid. THIS AGATE IS A WHOLE BUNCH LITTLER, and then there is that hole in the middle...

Now, the easy, and sensible thing to do at this point would have been to fit a friction jewel (like the ones used in watches) in the brass plug, and call it good. This would have taken a half hour, but then the jewels wouldn’t have matched. And besides, then I wouldn’t have had a reason to write this article about agates!

So, the easy first step was to get a slab of agate. My local rock shop came up with one, but kept looking at me sort of funny when I told them that I wanted to make a jewel out of it. That’s ok, he only charged me forty-five cents. Note, that is the least expensive part of this effort, and that is what the agate is made from. I also bought carborundum in four grits, 80, 200, 1000, and 1600.

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