- Well... the bow drill is a 'work in progress. The one in the picture works... but not as well as I'd like. I made my own 'bits' by taking concrete nails (square cut nails) and grinding down the head end to get the bit shape... on the end of the shaft had drilled an undersized hole and then driven a nail into the shaft. After pulling the nail... voila'... a socket.The drill does pretty well on soft materials and... as the 'bit' is tapered TOWARD the drive shaft (being a nail and all...) it naturally gives space for the waste in the hole you're drilling a place to go... The bow is the part that needs the most amount of work... just don't like how it feels... but thats a project for another day...Chas.On your web page you mention/show a drill that you made also, care to share any details regarding that?