Helix 15907 Right Hand Thread 1 Start Trapezoidal Lead Screw, 65mm Rod Diameter, 12mm Lead, 1800mm Length Lead screw with trapezoidal thread form for translating rotary motion into linear motion AISI 4140 steel for high fatigue strength and resistance to abrasion Rolled thread for stronger, smoother surface than cut thread Centralizing thread form for resistance to wedging and binding Right hand, 1 start thread