When sourcing Acme lead screws, you must prioritize Lead Accuracy (typically measured in inches per foot) and Pitch/Lead consistency. Ensure the material is C45 Steel or Stainless Steel (304/316) for the screw to prevent corrosion, and Bronze (typically SAE 660) or POM/Nylon for the nut to reduce friction. Verify the Thread Class (e.g., 2G, 3G, or 4G) to ensure the fit meets your precision requirements, and check for Straightness tolerances (e.g., 0.003 inches per foot) to prevent vibration at high speeds.