Welcome to this comprehensive guide for beginners on discovering the Jacot Pivot Lathe! If you’ve been looking for a detailed resource on this versatile tool, then you’re in the right place. In the following article, we’ll explore everything you need to know about the Jacot Pivot Lathe: from its history to its different parts and their functions, as well as some essential tips for using it effectively. So, whether you’re new to the world of precision watchmaking or a seasoned pro, read on to learn all about this fascinating tool.

Introduction

Whether you’re an aspiring watchmaker or just fascinated by the intricate inner workings of timepieces, the Jacot pivot lathe is an essential tool in your arsenal. This invaluable device is used during the process of repairing and servicing watches and clocks, particularly in correcting the pivots – the tiny spindles that support the gears – which can become damaged or worn through use or other factors.

In this comprehensive guide for beginners, we’ll introduce you to the Jacot pivot lathe and provide step-by-step instructions on how to use it effectively. We’ll also cover some common issues that arise during the repair process, as well as tips and tricks for maximizing your results.

What is a Jacot Pivot Lathe?

A Jacot pivot lathe is a specialized lathe that is used primarily for repairing and servicing watches and clocks. It is designed to hold and rotate the pivot – a tiny spindle that supports the gears – while the watchmaker uses a series of specialized tools to correct minor defects or damage. The lathe features a tapered center that is used to support the pivot, as well as a rotating headstock that allows for easy manipulation of the workpiece.

How to Use a Jacot Pivot Lathe

Using a Jacot pivot lathe effectively requires a combination of skill, patience, and attention to detail. Follow these steps for best results:

1. Secure the pivot in the lathe chuck. Begin by selecting the correct diameter of the chuck, then gently insert the pivot into the center hole. Tighten the chuck to hold the pivot securely in place, making sure it is aligned parallel to the lathe axis.

2. Check the end shake. End shake refers to the movement of the pivot back and forth within the jewel bearing. Too much end shake will cause the pivot to wobble, reducing accuracy and amplitude. Too little end shake will cause binding and increased friction. Check both the top and bottom jewels for correct end shake, referring to the manufacturer’s specifications as needed.

3. Verify side shake. Side shake refers to the ability of the pivot to move in an up-and-down direction within the jewel. Like end shake, too little or too much side shake can cause problems with accuracy and amplitude. Verify that the pivot is able to move freely while not being too loose.

4. Check for other issues. Common problems at this stage include incorrect end shake due to improperly set jewels or a broken pivot, as well as mesh wheels and pinions without corrosion or damaged teeth.

5. Inspect jewels. Make sure there are no cracks or breaks in the jewel holes themselves, and if there are, remove the jewel for jeweling.

6. Correct out of round pivot holes: Out of round brass pivot holes must be carefully repaired in order for the pivot to move smoothly. Investigate if there are any damages or corrosion causing any out of roundness.

7. Repair scratches on pivot. If there are scratches on the pivot, it may be due to a lack of lubrication. Use a smoothing brooch to carefully remove these scratches.

8. Repair pitting from corrosion or rust. Corrosion or rust will cause pitting on the pivot reducing amplitude. In this case, use a pivot lathe with a burnisher to correct the pivot.

9. Use a suitable burnisher. A hardened steel burnisher is ideal for correcting any grooves that may have been formed on the pivot, helping to restore it to its original shape.

10. Check for wear on sapphire runner beds. Modern watches often feature sapphire runners beds that are made of hard steel. These runners can gradually wear down over time, leading to increased friction and reduced accuracy.

11. Repair grooves or tapering with jacket lathe. A jacket lathe is used for correcting minor grooves or tapering on the pivot with a fine file.

Conclusion

The Jacot pivot lathe is an indispensable tool for watchmakers and clockmakers alike, and its proper use requires patience, skill, and attention to detail. By following the steps outlined in this guide, new users can quickly become proficient in its use and benefit from greater precision and accuracy in their work.

FAQs After The Conclusion

1. What is a Jacot pivot lathe used for?
   A Jacot pivot lathe is used primarily for repairing and servicing watches and clocks. It is designed to hold and rotate the pivot while the watchmaker uses a series of specialized tools to correct minor defects or damage.

2. What is end shake?
   End shake refers to the movement of the pivot back and forth within the jewel bearing. Too much or too little end shake can cause problems with accuracy and amplitude.

3. How do I check for end shake?
   Check both the top and bottom jewels for correct end shake, referring to the manufacturer’s specifications as needed.

4. What is side shake?
   Side shake refers to the ability of the pivot to move in an up-and-down direction within the jewel. Too little or too much side shake can cause problems with accuracy and amplitude.

5. What is a smoothing brooch?
   A smoothing brooch is a specialized tool used to remove scratches from the pivot of a watch or clock, restoring its precision and accuracy.