This premium cast-iron back plate allows you to mount a plain-back chuck to your lathe spindle. Models T10102?T10108 are sized to fit the plain-back chucks we sell along with the most common mounting configurations for lathe spindles. Made to precise specifications to allow you to mount your chuck with minimal preparations. If you also have an uncommon mount, we?ve got you covered with a 6", 8" or 9" blank back plate, which can be machined to just about any configuration needed. Great for mounting chucks to rotary tables, too!