Brace bits or brace shank bits are an old method of holding drill bits. Unfortunately they cannot be held in modern 3 jaw chucks. This design is an adaptor which allows these to be used on a power drill or impact wrench by utilizing a 19mm socket and socket driver.

Simply print the part and insert it into a socket then press the bit you want to use into the adapter it should wedge tight. The adapter has two holes for 6mm by 2mm magnets to avoid it dropping out of the socket, alternatively a drop of glue works too.