Elgin Watchmakers College Student Work

This is a brass plate with five different types of jewel settings used in train jeweling, in vintage watches. This was made at the Elgin Watchmakers Collage to show competency with the various jeweling techniques. All the parts, other than the jewels themselves are hand made from scratch as part of the project.

My grandfather made this during his time at the school in the 1930s.

Friction Jeweling

From The American Horologist and Jeweler magazine, January, 1946

Friction Jeweling
By E. Seibel

From the beginning of the use of jewels, which was inaugurated by one Facio in London, England, they have either been burnished into settings which in turn were set into the watch plates, or they have been burnished directly into the plates.

When set directly into the plates, it was quite a chore to replace, for you had to accommodate 3 ways. Naturally, you had to supply correct pivot hole, but you also were compelled to find a jewel of correct outside diameter and of the same thickness as the old jewel. If you could not do this you had to accommodate the seat in the plate to the jewel which you could supply of a larger outside diameter in order to get the correct endshake.

With a jewel put into a setting and then set into the plates, you set any jewel having the correct hole size into a setting which was then fitted into the recess already in the plate for the old jewel being replaced.

This enabled the factories to supply replacements and your endshakes were approximately correct. These set jewels were fastened into the watch by either burnishing them in or were held in place by 2 or 3 screws.

Now, a great many jewels are simply pressed into the plates with presses known as friction jeweling tools. 

The holes for the jewels are cut into the plates truly perpendicular with semi-circular reamers ground to 1/100 M.M. smaller than the jewel diameters. The jewels are ground to metric dimensions as to pivot holes and diameters of jewels themselves, and range from .70 to 3 M.M. by steps of 10/100 millimeters.

On examining these jewels we note a decided difference in the shape. The balance and cap jewels are domed as before and the train jewels are flat faced, but on examining the edges, we see they have a straight wall instead of a more or less sharp edge as the conventional design of jewels have had until recently. 

The friction jewel is rapidly replacing the older type and it is well for every first-class repairman to become thoroughly familiar with this mode of jeweling.

As said above, the holes to receive a friction jewel are reamed out 1/100 M.M. smaller than the jewel to be used and the jewel is then crowded down into this hole. First, it must be cautioned that the jewel must be tightly forced into its hole, or it may work loose.

There are a number of tools on the market which are more or less duplication of the tool made by Pierre Seitz, the originator of this method of jeweling watches and they all use the same principle. You have a set of punches, stumps and reamers which complement each other in the operation of replacing a broken jewel.

They all have a micromatic adjustment for the punches and a lever or screw arrangement which gives you an even and steady pressure on the jewel until you come to a stop at the position set by the micrometer screw.

It must be cautioned that punches and stumps must be in the best possible condition for this work, for if the punches are worn uneven or become rough, you can expect broken jewels in the operation.

You will find that in domed jewels such as Balance and Cap Jewels, it is wise to use the punch which has been chamfered out and the edge should rest close to the edge of the jewel.

On Train jewels, always use a flat face punch of a trifle smaller diameter of the jewel. 

If the few simple directions are used, it is possible to replace a broken jewel in a matter of 2 to 5 minutes.

Balance jewels come in diameter of 70 to 120 hundreds of M.M. Train jewels in same sizes for the very small pivot holes, and larger pivot hole jewels will run up to 230 hundreds of M.M., and center jewels will go as high as 260 and 300 hundreds of M.M. Cap jewels will range from 70 to 230 hundreds of M.M.

Balance jewels have holes size of 8-9-10-11 hundreds of M.M. and Train jewels, including center jewels, are made from 8 to 20 and then from there to 32 by jumps of 2 hundreds of a M.M.

A complete friction jeweling outfit as made by Pierre Seitz of Switzerland, who as was said above is the originator of friction jeweling is a considerable array of tools, consisting of the jeweling tool itself with 12 flat punches or pushers and 5 anviIs; a set of 11 concave pushers; a set of 15 reamers with holder; set of 12,pump pushers having pump centers, a face plate with 3 clamps for holding small bridges such as pallet bridges, a holder for holding jewel settings so that jewels can be replaced in them; a set of 12 centering points in stumps which have compression springs behind them.

These are not all necessary to be able to handle the ordinary job of re-jeweling; in fact, a really skillful and clever watchmaker needs only the reamers and possibly the stumps or anvils first mentioned, and the face plate with 3 clamps. The holder for jewel settings will be a welcome addition if he wants to replace jewels in separate settings. 

Q&A - What are Watch Jewels?

What are watch jewels and how are they made?

Watch jewels are typically synthetic ruby or sapphire. On some watches you will see the occasional diamond chip used, in a prominent place such as the cap jewel on the balance cock, just as a way to add some distinction.

These tiny donuts shaped parts support the moving parts in the watch. The extreme hardness of the jewel and the hardened steel pivots of the wheels form a very precise and long-lived bearing.

As an aside, I occasionally hear talk of how unscrupulous watchmakers sometimes steal the jewels from a watch.  This is one of those persistent mechanical watch myths that just never seem to go away. First of all the jewels in a watch are not valuable. Ans secondly, their function is completely practical, and not decorative. The watch will not run without them!

Find out more about watch jewels here:

http://www.rdrop.com/~jsexton/watches/museum/kyp/jewels.html 

Why Do Watches Have Jewels?

Why Do Watches Have Jewels? Is there a relationship between the jewel count of a vintage pocketwatch and its quality?

Vintage watches are completely mechanical devices with a lot of moving parts. Minimizing friction is critical in their design. Fairly early in watchmaking it was discovered that the combination of a sapphire or ruby and hardened steel make an extremely long-lived bearing. Garnets and diamonds are also used, but mostly for show. When methods of making synthetic jewels in a small doughnut shape were invented, around 1900, they became universal in watches. Jewels are also used as pallet stones in the escapement, where again their extreme hardness lets them hold the correct shape indefinitely. 

In early watches jewels are also used a "caps" over pivot bearings to hold oil in place and to keep dirt out. Generally, cap and cap-less pivot jewels are the only ones that can be seen on a watch movement, without disassembly.

In theory, a watch using more jeweled bearings could be more precise. A manufactured jewel will have a precise shape to very high tolerance. It can be made to hold oil in place and to greatly reduce friction. The idea that the use of jewels, more jewels, equates to higher quality was promoted by 20th century watch companies. The relationship is valid to an extent, but is clearly exaggerated. Synthetic sapphires and rubies are quite inexpensive to make, and so it's not unusual to see vintage watches with extraneous jewels that are really quite pointless.

Jewels have a disadvantage in that, like hardened steel, their hardness also leads to brittleness. They do not wear down like a soft metal, but they crack and break, failing catastrophically. On the other hand, it is simple to make a watch in such a way that jewels are easily replaced. But in general, a higher jeweled mechanism is likely to be less durable.

How are jewels for watches made? Learn more here!