This is a replacement Retaining Ring Cap Spring for Sailrite^® Ultrafeed^®, Leatherwork^®, Stitch Master^® and Yachtsman Sewing Machines.

The retaining ring cap spring is a small metal plate that sits across the top of the shuttle retainer ring in your Ultrafeed, Leatherwork, Stitch Master, or Yachtsman sewing machine. It plays an essential role in proper stitch formation.

If a needle becomes bent during sewing, it may strike the edge of the cap spring opening and create a small burr. These rough spots can lead to skipped stitches or broken thread—especially when sewing in reverse.

In some cases, burrs can be smoothed out so you can keep working. However, it’s a good idea to keep a spare cap spring on hand in case the damage is more severe. Fortunately, this part is inexpensive and easy to replace, secured by just two small screws.