PSI Woodworking LA3318 Headstock Spindle Adapter (M33 x 3.5 tpi to 1-Inch x 8tpi chuck) Adapts a spindle thread of M33-by-3.5 tpi to a 1-inch-by-8 tpi chuck Made of steel Has flats to allow wrench to hold when tightening Permits the use for different size accessories Extends the spindle over 1-inch