The aim of this study was to assess bone heating caused by the passage of fine (<2 mm) K-wires of different types. Stainless steel K-wires of trocar and diamond point configurations (0.8–2.0 mm) were drilled into the metatarsal bones from a freshly amputated lower limb at a constant force. Temperature measurements were made by miniature thermocouples inserted into the bones, at 3 second intervals over a period of 3 minutes while each K-wire was drilled three times. The temperature reached varied with the tip configurations and the diameter of the K-wires. Regardless of point configuration, thinner wires generated more heat than thicker ones.