Two Different Types of Thread Heads: The mounting mandrel of the die grinder features a handle with two different thread heads. This mounting arbor is designed to hold small diameter cut-off wheels or circular saw blades with a 3/8 inch or 1/4 inch center hole, with a journal length suitable for cutting discs from 0.035 inch to 0.16 inch thick. Shank dia x L: 1/4 x 1-15/16, #1 screw head dia x arbor dia x L: 3/4 x 3/8 x 5/8, #2 screw head dia x arbor dia x L: 3/4 x 1/4 x 5/8. Wide Compatibility: Cut-off wheel arbor with 1/4 inch (6.35mm) shank fits most die grinders and rotary tools. Easy to install and remove, making it a convenient accessory for grinding tasks. Durable: The cut-off wheel arbor is constructed from A3 carbon steel with a black plated finish for enhanced durability and rust resistance. Versatile: The mandrel can also be used to mount various grinding wheels, including grinding, sanding, cleaning, descaling, and polishing wheels, as well as HSS saw blades. Suitable for a range of applications. After-sales Service: We are committed to providing satisfactory customer service. If you have any questions about the product, please contact our customer service team. We will do our best to assist you. Package Included: As shown