The pilot stated that when he attempted to extend the gear with the normal system, it would not operate. He stated that he cycled the gear handle 4 or 5 times and checked the circuit breakers. Reportedly, he tried to extend the gear with the hand pump but it was jammed. Abrupt maneuvers were also tried, but to no avail. During a wheels-up landing, the propeller tips, belly skin, and nose gear doors were damaged. The pilot stated that after the landing, metal filings and shaving were found in the telescoping part of the emergency gear handle. Reportedly, he and two other persons had extended the handle with some difficulty before the investigator arrived. The investigator found no discrepancies with the normal or emergency gear systems. He noted that the two main tires were being held in the wheel well by the tires resting on the ground. Perpendicular scuff marks were found on the tires. The investigator tried, but was unable, to force the shavings in the emergency gear handle.