3. Friction Fit Jewels

The system of setting friction jewels in watch plates and bridges was started in Switzerland about 1920, but it wasn’t until the early 1930s that it was used to any extent in the United states. Friction jeweling tools were being developed about this time as well.

One of the early problems in friction jeweling was to develop a material for the jewels that would withstand the pressure of pressing them into the plate without breaking the jewels. This problem was solved by the development of synthetic ruby and sapphire. This material is much more uniform and stronger than the natural ruby and sapphire used in the early days.

Another problem was that the holes in the jewels were not always in the center of the jewel. Some of the American watch companies solved this problem by first placing the jewel in a brass setting and then while the jewel and it’s hole we’re running true in the machine, the outside diameter of the setting was turned to size. The jewel hole was centered into the setting. This jewel setting was then frictioned into the plate or bridge. After this, improvements in jewel making made it possible to friction the jewel directly into the plate or bridge and have the hole always on center which eliminated the need for the brass or gold jewel setting.

1.1 Seitz Jeweling Set

The following are some of the components that can be found in a Seitz friction jeweling set-see figure 1. The main part in the set is the frame which is very similar to the staking set tool except that it has a lever handle which is used to press on a pusher holder when the jewel is pushed into the plate or bridge.

Figure 1- Seitz Accessories

1.2 Reamers

There is a set of reamers for reaming out the holes to a predetermined size for the jewel. These reamers are graduated in sizes from 0.69 mm up to 2.99 mm in the following manner. 0.69, 0.79, 0.89, 0.99, 1.09, 1.19, 1.29, 1.39, 1.49, 1.59, 1.79, 1.99, 2.29, 2.59, 2.99. These sizes are 0.01 millimeters smaller than the jewels that are to be set in the holes that they ream -figure 1A

The reamer is shown in figure 1A. There is a holder for the reamer that has a tapered hole in its end into which the reamers friction fit into -figure 1B. One thing that’s important in the reaming operation is that a back and forth turning of the reamer should never be used. Always turn the reamer in a continuous clockwise direction in order to keep the hole in the plate or bridge round and on center. Also, never hold tight or lock the plate or bridge being reamed as that could very well cause the hole to be reamed off center.

1.3 Flat Pushers

In the jeweling set, there are three types of pushers for pressing the jewels into their holes. For pressing in train and jewels there is a set of flat pushers that are graduated in the following manner, 0.65, 0.75, 0.85, 0.95, 1.05, 1.15, 1.35, 1.55, 1.75, 1.95, 2.55, and 2.95. These are 0.05mm smaller than the jewel they are to push see figure 1C. Note that any flat pusher can also be used as a anvil/stump.

1.4 Concave Pushers

There is a set of concave pushers that are graduated in size the same as the flat pushers see figure 1D. These concave pushers are used for pressing in convexed balance hole jewels. The concave face of these pushers fits the convex face of a balance hole jewel which causes the pressure to be applied near the edge of the balance hole jewel instead of in its center where the jewel is weakest. This helps to prevent the jewel from being broken when it is being pressed into its hole.

1.5 Pump Pushers

There is also a set of pump pushers as shown in figure 1E. These are graduated in size the same as the other two styles previously mentioned. The faces of these pushers are shaped like the concave pushers except that in each one of these there is a small pump center. The purpose of this type of pusher is for mass production. When there is a large quantity of jewels to be pressed in, the pump center goes into the hole in the jewel and self centers the pusher on the jewel which makes it quicker to center the pusher on the jewel. This speeds up the operation. It also helps to prevent the edge of the hole for the jewel from getting damaged from a pusher that isn’t centered on the jewel. The pushers could be used on either train jewels or balance hole jewels. There is a spring loaded pusher holder for holding the pushers in the frame. This is shown in figure 2O.

1.6 Anvils, Stumps or Stakes

Seitz uses the term stake when referring to what most people refer to as stumps or anvils and should not be confused with the stakes in a staking set. These anvils are used to support the plate or bridge while the plate is being reamed, or when pressing the jewel into the hole in the plate of bridge. Some of these anvils are solid and others have graduated holes in them see figures 1F, 1 G and 1H.

1.7 Hole Closers

 Hole closers in the set are seen in figure 1I are used to close a hole in the plate for the jewel in the case the hole is slightly too large for the jewel. These are used to close the hole for a maximum of only 0.01-0.02 mm. These hole closers fit into the pusher holder see figure 2O.

Figure xx- hole closer

1.8 Setting Lever Pushers

This includes one stake and two pointed pushers. They are used to adjust the pallet fork when it needs to be adjusted up or down when adjusting for clearance see figure 1L

Figure xx- adjusting pallet fork lever

1.9 Lanterning Tools

This includes one stump and one pusher. Designed to tighten loose cannon pinions, lanterning can also be used tighten the pipes on second hands because very small adjustments, under 1/00th of a mm can be made- figure 1M.

1.10 Hour Hand Tightening

Similar to the convex pushers, hour hand tightening pushers do just what they say and come in 4 different sizes. Because of the small adjustments that can be made with the Seitz press, these are very valuable pushers to have – see figure 1J

Figure xx- closing hour and minute hands

1.11 Platform Stake

This is considered a stake or anvil but is better known as the table and is removed when using smaller anvils – see figure 1G

Figure 2- Additional Seitz Accessories

2 Premium Accessories

2.1 Face Plate

A more deluxe jeweling set has a face plate to hold small bridges and balanced cocks while reaming the hole for the jewel. See figure 2Q. This is a very handy attachment as it is always difficult to hold a small bridge any other way- see figure 3

Figure 3- face plate in use

2.2 Grind Stone

The grind stone is use to flatten the pushers if and when they need it. The ones I have seen have all been in bad condition and would either need to be dressed or discarded. The stone is used by moving it back and forth while pushing down on the spindle head-see figure 4.

Figure 4- grindstone in use

Here is a video I made on an alternative to using the grind stone for flattening pushers.

2.3 Holder for Jewel Settings

This set makes it possible to not only press jewels into settings but you can also ream settings as well. A full set includes collets to hold the jewel setting that are 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6. 1.8, 2.0, 2.3, 2.6 and 3.0 mm. The setting is placed in the collet and the collet fits into the table- see figure 5. The center knob opens the dog which has a hole on the end that fits over the collet. Then you tighten it down, it locks the setting in place. You can then press out the old jewel, ream it to clean up the jewel hole or ream it to enlarge the jewel hole on the setting.

Figure 5- Jewel setting (chaton) collets

If you are lucky a set may come with premade brass settings in the above sizes in the little aluminum vials see figure 2R.

2.4 Uprighting Pins

When a brass jewel hole or bush (a bush or bushing is a brass or bronze bearing), become worn on one side and is no longer round, a process known as uprighting is used to enlarge the hole so that it remains on center to the opposite pivot hole- see figure 6. Once the hole is enlarged a new bush can be inserted into the hole and then the pivot hole of the bush is reamed and then broached to fit the pivot or center jewe hole.

Figure 6- reaming a hole with uprighting pin

An example would be on a 7 jewel movement. A pivot hole in the bridge is out of round but the pivot hole in the mainplate is sound. You would install the bridge onto the mainplate and then install one of the correctly sized spring loaded pins loaded press frame- see figure 6 . The good pivot hole would be placed over the spring loaded pin. This pin establishes the upper pivot hole true to center over the lower pivot hole.

Then the damaged upper hole can now be reamed and have a new bushing pressed in. The image in figure 2V is a pin and spring that fit into the fixture base when the stake platform is removed and is used for uprighting.

2.5 Spindle with Collets

This spindle is a very nice accessory if you can get it. It can be used to hold cutting and smoothing broaches as well as micro bits. -see figure 2W. They are nice to have but I wouldn’t pay crazy money for one as most staking sets have something very similar minus the collets

2.6 Collet Holder

This holder is similar to the spindle with collets but is used primarily to hold winding stems when cutting and fitting them for crowns – see figure 2X. Nice to have but a regular pin vise is more than adequate.

2.7 Pivot Straightener

Premium sets come with a couple of pivot straighteners, one for balance pivots and one for train pivots -see figure 2Y and 2Z. A better name for them might be pivot breakers as I have never seen them used successfully to straighten a pivot.

2.8 Knurled Knob

The spindle -figure 2O, comes either with the head permanently attached and is a one piece unit or with a detachable head like in figure 7.

Figure 7- Spindle with detachable knob

One accessory that I really like is the knurled knob. To use this knob, the spindle is installed into the base and the knurled knob screws into the micrometer. Now the Seitz tool can be controlled like the Horia style tool- see figure 8.

Figure 8- Seitz Press with Knurled Knob installed

2.9 Pivot Gauge

Some jeweling sets will come with a pivot gauge. The gauge is fitted with jewel holes starting at 0.07 mm and go up 1/100 of a mm all the way to 0.50 mm – see figure 9. Incredibly expensive to buy separately, but if you have one they are handy for measuring pivots . They can also be hard to find in good condition as many of the pivot holes can be broken from misuse. Personally I think a good digital micrometer is a better investment and will have way more uses to you in watchmaking.

Figure 9- jeweled pivot gauge

2.10 Burr Removing Tool

Sometimes the jeweling set has a burr removing tool used for removing the burr from around the hole after reaming. In most cases you will have to buy new ones. This burr is created by the reamer when the hole is reamed. If the jeweling set doesn’t have this tool other means can be used to remove the burr.

One of the best ways is to use a wheel countersink as shown in figure 10. These wheel counter sinks can be bought from watch material supply houses. They usually come in sets of six. Some are double ended. On both ends there is a disc with a sharp edge for cutting or sinking around a hole. In some older vintage models one disc has a rounded edge for burnishing and polishing the sink that was previously cut by the sharp edge disk.

Figure 10 – Bergeon 1897

Another way to remove the burr from around the reamed hole is by the use of a round dental burr as in figure 11. Dental burrs can be installed into a pin vice to make them easy to use. If neither of the two mentioned burr removers are available then the beveled point of the reamer can be used in a pinch. Select one that is about two times larger than the hole that has the burr to be removed.

Figure 11 – dental burr

1.9 Buying Vintage Jeweling Sets

If you plan on working on movements made post 1930 with friction jewels and you are just starting out, the Horia style clone jewel press will work fine if you are on a budget. If you plan on working on movements pre 1930 with rubbed in jewels or jewel settings, you are going to want a Seitz press. These were designed to be able to work on the movements from that era.

There are multiple brands like Favorite, C&E Marshall, K & D but Seitz was the original and is the one I have always used.

Purchasing them can be somewhat of a minefield when it comes to condition. My best advice is to ask lots of questions and try to buy as complete a set as possible. Pushers that can’t be redressed can still be bought new for Seitz presses. Reamers that are damaged can’t usually be re sharpened but can also be purchased new as well. Many of the vintage accessories above can also be bought separately on eBay.

2. Jewel Types

Friction fit train jewels only come in a couple of different configurations- see figure 12. They are straight sided and have a curved edge on the oil sink side of the jewel. This is the side that goes into the hole when the jewel is being pressed into the plate or bridge. Center wheel jewels are classified separately because of the large center hole. Cylindrical hole jewels-figure 12A are what you will find in most other train jewels with olive train jewels- figure 12B, will be found in high grade movements.

Figure 12-Train jewel styles

3. Selecting the Proper Jewel Size

To replace a damaged friction train jewel, the old jewel is first removed from the plate or bridge. This can be done with a flat jewel pusher that is slightly smaller than the jewel. The plate or bridge is supported on a stump that has a hole in it large enough to for the jewel to fall into as it is pushed from its hole. This stump should be of such a diameter to fit into any recess around the jewel hole to that the plate or bridge sits flat on the stump.

After the old jewel is removed and if it comes out in one piece, it can be measured with a micrometer to determine its outside diameter when selecting a new jewel.

Figure 13 – Reamer

For example if a reamer sized at 1.39 mm is put into the jewel hole and doesn’t go all the way in, past the cutter, drop down one size and try the reamer sized at 1.29 mm. A reamer that is correct for a hole will be able to be inserted past the cutting surface to the burnishing section of the reamer.

Jewel’s common outside diameters are graduated in millimeters as follows 0.70, 0.80, 0.90, 1.00, 1.10, 1.20, 1.30, 1.40, 1.50, 1.60, 1.80, 2.00, 2.30, 2.60 and 3.00.

Train jewels diameters are graduated in the following way. Olived Jewels are available from 0.70 to 1.2 mm wide and jewels with flat cylindrical holes are available from 0.80 to 3.0 mm- see figure 14.

Figure 14- jewel chart

After the diameter of the jewel is determined then the pivot hole size needs to be determined. If the hole in the old jewel isn’t damaged its size can be determined by the use of plug or pin gauges.

If the jewels pivot hole is damaged, the pivot that works in this hole can be measured and the jewel selected that has a hole 0.02mm larger than the pivot for the train jewel or that is 0.01 millimeter larger for a balance hole or pallet hole jewel.

If a jewel cannot be located with the correct pivot hole size with the same outside diameter as the old jewel, then a jewel is selected that is one size wider than the old jewel. The plate hole is then enlarged with a reamer to fit the new jewel width. It is always best to select the new jewel with the same diameter as the old one if possible.

3. Removing and Installing Jewels

3.1 Setting Depth

If the new jewel needs to be pressed below flush in order to have proper end shake, the pusher selected should be slightly smaller than the jewel being pressed out.

The micrometer adjustment on the Seitz press is graduated in 0.01 millimeter increments. Before the old jewel is removed from the plate, this micrometer adjustment can be set while the pusher is resting down against the flat side of the jewel. Once this measurement is determined, the new jewel can easily be pushed to the same depth as the old one.

To set the micrometer adjustment, select the stump and a pusher that is to be used for pressing in the new jewel. Then place these in the jeweling tool making sure they are installed fully.

Now place the plate with the jewel into position on the stump and bring the pusher down on the old jewel. Now turn the micrometer clockwise to lower the pusher until it rests on the jewel. This index’s the pusher to the jewels position in the plate or bridge. Record this measurement.

Remove the plate and lower the pusher by turning the micrometer clockwise one full revolution which is one millimeter. If the micrometer reading from the jewel was .03, turn the micrometer one complete turn and stop on 0.03. This should be enough to push out most jewels you will run into.

If the new jewel is to be pushed flush with the plate, then the micrometer adjustment is not needed.

Pressing In Jewels

To set a friction hole jewel, the old jewel is first removed. To do this select a stump with a hole in it that will clear the jewel as it is removed. Now select a flat pusher or pump pusher that is slightly smaller than the jewel. Place the stump in the jeweling tool table and the pusher in the pusher holder. Always push down on the flat side of the jewel when possible. Now place the plate with the oil sink side facing down on the stump. Then bring the pusher down centered on the jewel and press the jewel out.

Note: a balance hole jewel is pushed out from the inside of the plate and pushed in from the outside of the plate.

Once the old jewel is removed, select a new jewel with the proper outside diameter and pivot hole size. Then select a flat or pump pusher slightly smaller than the jewel if the jewel is lower that the plate surface and slightly larger than the jewel if it is to be flush with the plate or bridge.

When the pusher has been selected place the pusher into the pusher holder. If the jewel is pressed below flush with the plate, dial in the measurement you recorded before the old jewel was removed.

Then position the jewel into place in the hole with flat side facing up. Now place the bridge or plate on the stump. Bring the pusher down, centered on the jewel and push in.

If you are replacing a balance hole jewel, it must be pushed down until the top of the jewel is 0.02 mm below flush with the plate. This is a common spacing amount but can vary slightly depending on the caliber. Therefore the plate must be measured as well as the jewel depth to know the correct depth the balance hole jewel requires. The reason the balance hole jewel is commonly set to 0.02 mm below flush is to allow for oil space between it and the cap jewel.

To actually measure this 0.02mm, the micrometer stop can be used. To do this, select a stump to support the plate or balance cock. Place this in the jeweling tool frame. Now select the smallest flat pusher in the jeweling set and place this in the pusher holder.

Then place the plate or balance cock on the stump in the tool. Now bring the pusher down on the plate beside the jewel where the endstone sits. After this is done the micrometer stop can be backed up against the head of the pusher holder, which sets the micrometer adjustment. Take a reading of what the micrometer adjustment shows.

Now move the plate on the stump until the pusher is over the jewel. Slowly turn the micrometer stop until the pusher just touches the top of the center of the jewel and record this measurement.

The difference between these two readings will be how far below flush the jewel is.