All About Jewels
Are they really jewels? And what are they doing inside an old watch?
Learn about the different kinds, what they're made from, where they're used, when they need to be replaced, what they do for accuracy, how to identify the count when the watch is not marked, and much more.
Types of Jewels
Hole and Cap
Watch companies used semi-precious gems like garnets, rubies and sapphires as bearings to reduce friction between certain components of a watch. The two primary types are hole and cap jewels, and both have their functions on the balance assembly and in the gear train. Think of the difficulty involved in making these tiny, brittle parts after mining the raw minerals and cutting them into usable shapes.
Jewels in Settings
Both hole and cap jewels could be mounted in a setting made of brass, bronze, and even gold. The setting was a ring with an inside shoulder to hold the jewel in place, while a press crimped the metal edges of the setting over the jewel, securing it.
Diamond Cap Jewels
Diamonds were used as cap jewels on the balance staff and on the escapement of the very highest grades. While they increase its value, the diamonds themselves do not increase its accuracy.
Which watch had the most? Waltham's legendary Riverside Maximus came with three pairs of diamond cap jewels, for a total of six.
Roller Jewels
Sometimes referred to as the impulse jewel, this stone trips the pallet fork in the opposite direction by every arc of the balance wheel while absorbing millions of impacts during its service life. The roller jewel is mounted to the roller table of the balance wheel with shellac, a gummy naturally-occurring resin secreted by the female lac bug.
For more information on roller tables visit the Advanced page.
Pallet Stones
These stones are also mounted with shellac to the pallet fork, which momentarily halts the gear train at every tooth of the escape wheel and simultaneously pushes the balance wheel through its oscillations. It's the precisely angled faces of those two stones, driven by the mainspring, that impels the balance wheel into its next cycle.
Jewel Functions
Hole Jewels
Hole jewels were used as simple bearings for polished steel pivots that generated very little friction when properly oiled, relying on the flat face to control end shake, which is vertical travel. They were made from industrial-grade precious stones, so they were much harder than the steel gear train pivots but even more brittle.
Capped Jewels
Cap jewels provide a rebound surface for the pivot tips, eliminating the need for the flat surface used on hole jewels. Paired hole and cap jewels trap the staffs by their tips, generating less friction than hole jewels alone because smaller surface areas come in contact with each other.
Escapement Jewels
Jewels were also used in lever escapements, which was the eventual design choice of most watch factories. The roller jewel, mounted on the balance wheel, gives the impulse to the pallet fork, alternately locking and releasing the entry and exit pallet stones. This allows the escape wheel to rotate one tooth at a time, gradually letting down the mainspring until it's spent.
When To Replace Jewels
After well over a century of service it's difficult to find an antique pocket watch that doesn't have at least one cracked or broken jewel. Replacing every flawed jewel would not only be impractical but very expensive, so when is it all right to leave a cracked jewel? Is it ever all right?
The decision to replace a gear train jewel depends on two things: where the jewel is in the gear train and how badly it's broken. The balance wheel rotates the fastest out of all the other components - roughly 18,000 times an hour, so any cracked or broken balance jewel must be replaced. At the other end of the gear train is the mainspring barrel, which makes a complete revolution about every three hours. The center wheel rotates once an hour, the third wheel in every fifteen minutes, the fourth wheel once a minute, and so on. This means that the mainspring barrel, the center wheel, and the third and fourth wheels don't spin fast enough to generate any appreciable friction, so if those jewels have simple cracks they can generally stay in service. Of course, if they're shattered they must be replaced. What's the difference between cracked and shattered? Read on . . .
Simple Crack
This is a simple crack, one that involves the arbor hole. There are cracks called chords that pass from edge to edge without involving the hole. Both types of these simple cracks are closer to a flaw in the stone than any real damage and can stay in service as long as they're higher up in the gear train and not on the balance staff or pallet fork because there is no loss of surface (face) and the jewel itself is stable in the setting.
Shattered Jewel
Keeping in mind that the function of a jewel is to reduce friction for its associated gear train pivot and to provide a flat rebound surface, this jewel is shattered and therefore useless. The arbor hole is jagged and would grind the softer steel pivot down to nothing, and it is no longer mounted securely in the setting. This jewel must be replaced, regardless of where in the gear train it's located.
Jewel Settings
Bushings
Flush Friction
Press-Fit
Bushings are not jewels. They are holes drilled into both upper and lower plates for the gear train components. The contact between all of the parts is metal on metal, and unless they're properly maintained the bushings will enlarge and become ruined.
Press-Fit
Flush Friction
Press-Fit
Holes with stops were milled into the plates, an unmounted jewel inserted into the hole, and then the plate metal was rolled over the edges of the jewel, trapping it in place. These are not meant to be replaced, and they must be shattered before they can be removed.
Flush Friction
Flush Friction
Flush Friction
These jewels were mounted in settings and then seated from the inside so they can't fall outward, and flush with the plate surface. Friction keeps the setting tightly in place, so they're easily changed if necessary. This is also known as an interference fit.
Flush Screw
Raised Friction
Flush Friction
Unlike friction-fit jewels, these kinds of settings were almost always screwed in from the top side of the plate, though there are several exceptions. The settings were carefully milled flush with the plate so they couldn't interfere with the oscillation of the balance wheel on full-plate designs.
Raised Screw
Raised Friction
Raised Friction
Sometimes called smokestack jewels, these settings were usually made of gold and were again screwed in from the top of the plate. The purpose of raised settings was partly for show, but they also did a better job of retaining oil because of their cupped shape so that it didn't migrate onto the plates.
Raised Friction
Raised Friction
Raised Friction
These are also raised for oil retention but are pressed in from the inside. They are used for a clean look on only the higher grades and are almost always gold. Any cap jewels, which must be installed first, are not a snug fit and are kept in place by the friction-fit hole jewel, which is installed second.
Jewel Locations
There are seven gear train components in any American railroad-era watch, no matter the size or model, making for seven jeweling locations. The exceptions are 5th pinion designs by Illinois and Aurora, which converted hunting movements to open-face.
- The mainspring barrel, which provides power
- The center (second) wheel, which drives the hands
- The third wheel between the center and fourth wheels
- The fourth wheel, which holds the seconds hand
- The steel or bronze escape wheel
- The pallet fork with entry and exit stones
- The balance wheel, which carries the roller jewel
The pallet fork utilizes two pairs of hole/cap jewels and two stones on a higher-count watch, while any balance wheel uses two pairs of hole/cap jewel plus the roller jewel.
5th Pinion Watches
An Extra Idler
Illinois and Aurora were two companies that produced hunting movements with a standard gear train, and simply modified their existing designs to achieve an open-face watch rather than go back to the drawing board and come up with a completely new model.
The 4th wheel on a hunting movement (yellow arrow) carries the second hand, and to convert it to open-face the factory simply added an extra idler (red arrow) 90 degrees away from center so that it was opposite the winding stem and mounted the seconds hand there.
5th pinions can also be jeweled, singly and in pairs, adding to the count.
Low-Grade Counts
7 Jewels
Metal On Metal
Metal On Metal
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones (1 entry and 1 exit)
- 1 roller jewel
Seven was the lowest total for most American watch brands, and was the basis for all higher counts, with no jewels in the gear train.
Metal On Metal
Metal On Metal
Metal On Metal
The purpose of jewels was to reduce friction between the gear pivots and the plates in which they rotated. The gear train in a 7-jewel watch used bushings instead of jewels, and over time the pivots and the bushings can wear badly, especially with poor maintenance, and once these bushings become enlarged the watch is essentially ruined.
7 Jewel Fakes
Metal On Metal
7 Jewel Fakes
Several factories made 7-jewel watches with glass cap "jewels" on top of every pivot, along with false jewel counts and railroad motifs stamped on the plates. Underneath are metal bushings, though the glass caps may keep a certain amount of dust out of the pivots. The micro-regulator on the balance is functional.
9 Jewels
11 Jewels
7 Jewel Fakes
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 hole jewel each for the pallet staff and the escape wheel
It is believed that Rockford was the only factory to offer this jeweling combination of two train jewels on the upper plate only.
9 Jewels
11 Jewels
11 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the escape wheel
It is believed that South Bend was the only factory to offer this jeweling combination of a pair of jewels for one train component.
11 Jewels
11 Jewels
11 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape wheel, for a total of four
The only possible tip-off between a 9 and an 11-jewel watch is that the higher count may have a micro-regulator.
11 Jewels
11 Jewels
11 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 hole jewel for the pallet staff, the escape wheel, and the 3rd and 4th wheels, for a total of four
All the jewels are on the upper plate and none are under the dial. The tip-off between an 11 and a 15-jewel watch is that the lower count will usually have only a simple regulator.
12 Jewels
11 Jewels
11 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 hole jewel for the pallet staff and the escape, 3rd, 4th, and center wheels, for a total of five
Again, all of the gear train jewels are on the upper plate, with corresponding metal bushings on the pillar plate.
13 Jewels
11 Jewels
13 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet staff and the escape and 4th wheels, for a total of six
A very unusual count, but a practical one since the upper gear train doesn't rotate fast enough to generate any appreciable friction.
Mid-Grade Counts
15 Jewels
15 Jewels
15 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet staff and the escape, 3rd, and 4th wheels, for a total of eight
The tip-off between a 15 and an 11-jewel watch is that the one with higher count will usually have a micro-regulator.
16 Jewels
15 Jewels
15 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet staff and the escape, 3rd, and 4th wheels, for a total of eight
- 1 upper center wheel jewel
Several companies did not jewel the center wheel under the dial, possibly to lower costs.
17 Jewels
15 Jewels
17 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
All the components are jeweled except for the mainspring, which rotates too slowly to generate any appreciable friction.
19 Jewels
19 Jewels
17 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of jewels for the external mainspring barrel arbor
19 Jewels
19 Jewels
19 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of jewels for the mainspring arbor inside the barrel
19 Jewels
19 Jewels
19 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of cap jewels for either the pallet staff or the escape wheel
High-Grade Counts
21 Jewels
21 Jewels
21 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of cap jewels for the pallet arbor and the escape wheel, for a total of four
21 Jewels
21 Jewels
21 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of cap jewels for either the pallet arbor or the escape wheel
- 1 pair for the internal mainspring arbor
22 Jewels
21 Jewels
22 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of cap jewels for the pallet arbor and the escape wheel, for a total of four
- 1 hole jewel for the external mainspring arbor
23 Jewels
23 Jewels
22 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of cap jewels for the pallet arbor and the escape wheel, for a total of four
- 1 pair for the mainspring arbor
23 Jewels
23 Jewels
23 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of caps for the pallet and escape wheel, and 1 each on the upper 3rd and 4th wheels, for a total of six
23 Jewels
23 Jewels
23 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of cap jewels for the pallet arbor and the escape wheel, for a total of four
- 1 pair of jeweled banking pins
Non-Functional Jewels
Non-Functional Jewels
Non-Functional Jewels
Jeweled banking pins artificially inflated the count and did not increase accuracy. This design is found on the Howard Series O.
Why are they non-functional? Because there is virtually no friction between the pallet arm and the banking pins, which act as stops for the pallet as it swings rapidly back and forth. It is this action that produces the tick-tock sound that you hear.
24 Jewels
Non-Functional Jewels
Non-Functional Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of caps for the pallet arbor, escape and 3rd wheel, and 1 on the 4th wheel, for a total of seven
24 Jewels
Non-Functional Jewels
24 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of cap jewels for the pallet arbor, escape wheel, and 3rd wheel for a total of six
- 1 hole jewel for the upper mainspring barrel
25 Jewels
25 Jewels
24 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of cap jewels for the pallet, escape and 3rd wheels, and 1 on the 4th wheel, for a total of seven
- 1 hole jewel for the upper mainspring barrel
Only the Columbus, Illinois, Rockford and Seth Thomas factories made 25-jewel watches as regular production pieces. Rockford made the fewest with only a dozen or so, and Seth Thomas made the most with around 720.
26 Jewels
25 Jewels
26 Jewels
- 2 balance staff hole jewels
- 2 balance staff cap jewels
- 2 pallet stones
- 1 roller jewel
- 1 pair of hole jewels for the pallet and the escape, 3rd, 4th, and center wheels, for a total of ten
- 1 pair of cap jewels for the pallet, escape and 3rd wheels, and 1 on the 4th wheel, for a total of seven
- 1 pair of hole jewels for the mainspring barrel
Illinois was the only company to offer a 26-jewel watch, and roughly 250 of those were produced in three grades: the Bunn Special, Benjamin Franklin and Pennsylvania Special. Photo courtesy of Jones & Horan.
28 Jewels
25 Jewels
26 Jewels
For years it was thought that Seth Thomas made a 28-jewel variant, the single highest total of any American watch produced during the railroad era, printed in the Fat Book, or the Complete Guide to Pocket Watches.
Did they make such a watch? Join the Seth Thomas Research site and find out.
Jewel Count and Accuracy
Low Versus High
As previously described above, a 7-jewel watch was the lowest production model made by nearly all American companies at one point in their history. All of these brands were the same when it came to the balance assembly, containing of a pair of hole jewels and a pair of cap jewels for the balance staff, the entry and exit pallet stones, and the roller jewel, for a total of seven.
Any other jewels were in the gear train, but these have very little to do with accuracy, especially those that are higher up in the train, like the center wheel or mainspring barrel. 7-jewel variants can be just as accurate as 23-jewel ones, as long as everything in the escapement is within factory specs.
Don't believe it?
7 Jewels
Here is a very common 12-size Model 3 Elgin with only seven jewels, which are all in the escapement, but none in the gear train. The rate and beat error both show zero on the Timer, but since a certain amount of mainspring torque is lost to friction in the unjeweled gear train, the balance arc is still a healthy 250 degrees.
23 Jewels
And here is a top-shelf 23-jewel Waltham Model 92 Vanguard with diamond caps and adjusted to all kinds of positions, also showing rate and beat error at close to zero. The difference is sixteen jewels in the gear train, which eliminates a small amount of friction and allows the balance arc to run a little hotter at 310 degrees.
Jewel Envy
Both of these watches showed a rate of zero on the Timer, which is the amount of time lost or gained in seconds within a 24-hour period. Think about that for a moment - all of those extra jewels (some of them even diamonds) that could be easily broken, meant solely to drive up the selling price, and none of them made the watch any more accurate, as long as it was maintained well. And twenty-three wasn't the lowest count!
Restoration Highlights
One of Illinois's rarest watches was the 23-jewel Washington Lafayette. Only 190 were ever made.