The hand brace is an essential and versatile tool that should be in every shop. In many instances, a hand brace can bore holes to precise angles and depths more easily and more accurately than a cordless drill. The problem with using a hand brace is the choice of quality square shank bits is quite limited. Used vintage bits can be found at swap meets or online, but quality can be quite variable, and they will likely need sharpening. New bits can be found, but they can be quite expensive, or quality is poor or inconsistent. This adapter has square and tapered end and fits perfectly in any hand brace chuck. The other end accepts 1/4 inch hex shanks. This adapter with fixing screw holds these bits secure in place. Specifications: 1) Hex shaft accepted: 1/4 inch (6,35mm) 2) Depth of hole: .820 inch 3) Screw position: .275 inch from end 4) Outside diameter: .550 inch 5) Overall length: 4.5 inch 6) Secured with round knurled steel knob