Possible Clues:

• For forging, perhaps, can you beat that?
• Five in nothing - can you beat that?
• It's for Smith to have lain about five. Can you beat that?
• Forge equipment
• Bone found in Mexican village
• Where one could hammer out one crooked nail about five
• Block on which metals are hammered
• Cartoon prop, often
• Smith's heavy iron block
• It always gets a hammering