The Horia Jeweling Tool
What is a jeweling tool? Jewels in wristwatches serve as bearing surfaces for pivots. Essentially a gear (wheel) has an axle and the axle rides between two jewels. The axle needs to have some freedom of movement (or endshake) to allow it to rotate freely but not so much as to keep it from lining up with the next wheel when the watch changes position. In most watches the average endshakes range from .01mm to .05mm. In order to adjust the endshake for a particular wheel we move the jewel up and down in the plate. The jewels in modern watches are held into place by friction and can be moved up or down. (This wasn’t the case in older watches.) A jeweling tool is used for installing frictioned jewels and for adjusting the endshake.
There are several different jeweling tools. The most common is probably the Seitz jeweling tool. It is a levered press and takes some getting used to. The Horia tool is (in my opinion) far superior.
The pushers and stumps are fit to the tool to match the size of the jewel. To move the jewel you turn the micrometric feed on the top. Each mark on the dial represents approximately 0.02mm of vertical movement. It’s a beautiful tool. It can also be used for removing and installing pallet staffs and adjusting tension on traditional style cannon pinions. I’m sure there are more uses, if you know of any add a comment.
One advantage to the Seitz tool is the ability to raise the lever out of the way and use the reamers for opening (or forming) jewel holes. A good staking set will supply you with this functionality as well.
The Horia company is a very small company which specializes in watchmaker’s tools. They make some of the finest 8mm watchmaker’s lathes, jeweling tools, Jacot Tools, and Automatic Burnshers available today. They’re not cheap but they are quality precision tools.
Note: There are two versions of this tool, one where the stumps and pushers are different diameters, and one where they are the same. I have the one where they are different. I recommend you get the one where they are the same, it will then be comaptible with all of the Seitz stumps and pushers as well as the specialized stumps made for Incabloc shock settings. I had to modify a set of Incabloc pushers so I could use them in my tool.