A good jewelry mandrel will not only give you the correct ring size of a ring but also allow you to do other tasks like sizing rings and jewelry repair with the mandrel’s assistance. There are two distinct jewelry tools that are considered mandrels; the first is a sizing mandrel and the second is a part for a polishing motor or device. This second kind of mandrel is used to attach a polishing, buffing, grinding, or diamond wheel or disc to the polishing motor to allow you to mechanically finish your jewelry project. They are also commonly used on flex shafts and dust collectors.