your ring on a lathe 10x easier to make rings compared to using a rotary tool or other methods. You get a much more professional finish most of the time. If you're making more than one size ring, this steel expanding ring mandrel set is a because you can easily swap out any size and have a snug fit within seconds This Large expanding ring mandrel for lathe fits ring sizes 7.5 to 10.5 This set also includes an Hex wrench to expand and contract the mandrel. It has 7inch base to fit a variety of chucks and can be used in a lathe or drill It's effortless to use this expanding mandrel for lathe. There is extra room on each ring size to accommodate tape to keep the inside of your rings scratch-free. For proper function, apply a layer or two of tape to you be using. This helps protect the inside of your ring Expanding mandrel offers a high level of precision when making rings. Designed to be used in a lathe. Also fits in 1/2inch drill chuck. Our expanding ring mandrels for ring making are made with wear- steel. While other materials such as wood or carbon steel rust or wear down, these ring expanders withstand the test of time even with heavy use Color: As Shown Material: stainless steel Package Contents: 1 pcs x ring mandrel Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.