Sometimes, a watch comes in for service, and everything looks great, except the watch doesn’t work. Here are some things you should know about determining if the watch has a broken roller jewel…
- Balance wheel spins, but the watch does not tick
- When you remove the balance from the watch, you can move the pallet fork, and the watch runs one clock at a time
- No damage is visible
- Examining the Balance, you see that there is no jewel on the roller table!
What is a roller jewel?
The roller jewel is placed on the underside of the complete balance, onto a roller table. The roller table is pressure fit onto the balance staff, and oscillates back and forth with the force of the hairspring, and the pallet fork putting back and forth pressure onto the roller jewel. If the jewel is missing, the fork will not work properly, the balance wheel will not oscillate, causing the tell tale “Clicking Noise” that we hear from a mechanical watch.
Is the roller table and Jewel repairable?
Yes, and I’m going to put this forth right now. This is one of the most difficult tasks to undertake when fixing a watch. As you can see in the video here, the roller jewels are very small. They will slip out of your tweezers easily, and due to the small parts, I recommend that you get a magnifier of at least 3x, or use a microscope to set the jewel, and lacquer it into place.
What tools will I need to work on the roller table & jewel?
You will need the following tools to work on this repair, and you’ll need some time to practice. Don’t be intimidated by this repair, as it took me several times to perform this my first try. The video is about 34 minutes long, and I did that to show you that there are times when you’ll get a bit frustrated, due to the small parts. However, I can perform this task on a pocket watch in about 15 minutes. Wrist watch versions of this same repair will often take me about 25 minutes.
- Watch makers screwdrivers
- A watchmakers Staking Set
- Roller Table remover, for your staking set
- Roller Table Heater
- New Roller Jewels (That fit the model of the watch you’re working on)
- Flaked Lacquer
- A heat source, in my case, I use a candle
- Brass or Rawhide Hammer
- Small Hand removers or Hairspring Remover Tool
- Optional – Soft Top Bench Pad
- Magnification Visor or Microscope
- Good Lighting!
How to Properly Align the Hairspring and Balance Wheel
You’ll notice that in the picture (Figure A), that I’ve highlighted a red line. This line represents the alignment from the balance staff, to the roller jewel, and onto the escapement staff. It is a straight line, and the roller jewel should be in between the balance staff and the escapement staff.
Once you place the Hairspring onto the top of the balance, it must be aligned so that the Roller Jewel is along that line, and that the hairspring pin aligns with the hold on the balance cock.
Figure B shows how I hold up the balance wheel above the balance cock, so that I can gently turn the hairspring collet and hairspring so that the pin aligns properly with the hole in the balance cock. Once I’ve made sure that the alignment of the roller jewel and the hairspring pin are correctly in position, I can not attach the balance to the balance cock, as shown in the video. In the video, you can see that I use a small screwdriver, and place it onto the hairspring collet, within the open groove in the collet, and gently twist, so that the hairspring turns on the balance staff. While performing this, you must be careful to to apply too much pressure so as not to damage the hairspring or the balance.