Re: Countersinking with hand drill?
If you have a fine grinding wheel, you can carefully shape a large drill bit to the angle of your fastener. Some practice on scrap would help. If your bit is a sharper angle than the screw, it will fit okay. If the angle of your screw head is sharper than the bit, it will not go flush. It also depends on how structural, or strong, it has to be. The better the fit, the stronger the connection.