Hammer's partner is a term used to describe the tools that are used in conjunction with a hammer. The first tool is an ARM, which is a three letter word. An ARM is a tool that is used to hold nails in place while they are being hammered into a surface. The second tool is TONGS, which is a five letter word. TONGS are used to grip and hold objects, such as nails, while they are being hammered into a surface. The third tool is a NAIL, which is a four letter word. A NAIL is a small metal object that is driven into a surface with a hammer. All of these tools are essential for any job that requires hammering.