This month's mystery item is a chain drill, and if you've ever had to drill on a curved surface, you know how handy this tool can be. It uses the rotary motion of a bit brace to tighten a chain, thus feeding the drill into the workpiece. This type drill was used extensively for drilling into pipe or round bar. The chain served to steady the workpiece in addition to providing constant pressure on the drill.
This month's mystery item is a chain drill, and if you've ever had to drill on a curved surface, you know how handy this tool can be. It uses the rotary motion of a bit brace to tighten a chain, thus feeding the drill into the workpiece. This type drill was used extensively for drilling into pipe or round bar. The chain served to steady the workpiece in addition to providing constant pressure on the drill.
This pic from