The pilot reported that he conducted a preflight inspection of the airplane, and that during the takeoff roll, he pulled the yoke back to stop the nosewheel from shimmying, added power, checked the engine performance, and then added more power. The airplane’s nose dropped slightly, and he added more power. Subsequently, the nose dropped further and contacted the ground. The pilot reduced engine power, and the airplane then skidded down the runway and exited onto grass, which resulted in the right forward fuselage, right outboard wing, and right horizontal stabilizer and elevator sustaining substantial damage. One of the first steps of the Preflight Checklist is “Landing Gear Lever – Gear Down.” The pilot reported that he liked “to touch each item” as he called it out but that he “did not do that on this phase of flight.” According to the mechanic who recovered the airplane, he found the landing gear “handle” in the “up” position and the nose landing gear and right main landing gear retracted. The mechanic was able to extend the gear using the emergency hand pump. He then turned on the master switch and saw a green gear position light, indicating that all three landing gear were down and locked. The mechanic added that he did not see anything that would have caused the gear to collapse.