Workmanship Standard for Burrs on Lead Screws

  • All metal and plastic parts shall be deburred. Inspection for burrs will be carried out using the Cosmetic Inspection criteria. (see below) There shall be no visible burrs.
  • Where machined surfaces meet the lead screw threads, the edge of the first 1-2 threads should be chamfered and/or ends buffed with a light abrasive wheel to round edges and remove sharp edges or burrs.
  • Burrs resulting from screwdriver slots, cross holes, keyways, flats, etc should be deburred by hand or buffing wheel. Care should be taken not to damage or impact dimensions of adjacent

Cosmetic Inspection

The detection of cosmetic defects is largely subjective, affected by lighting and personal perception. Where cosmetic criteria must be evaluated, the inspection will be carried out under the following conditions unless specific requirements are made elsewhere in this document.

  • a) The part will be viewed for no longer than 10 seconds.
  • b) The part will be held at a distance of 6-12 inches. Magnification can be used for
  • c) Lighting will be cool white florescence or LED as is normally found in the inspection, shop and office areas.

If a defect is not visible under these stated conditions, it shall be considered non-existent. Repetitive cosmetic inconsistencies that occur in the same place are more easily noticed. If a part was judged acceptable at the beginning of lot inspection, the same inconsistency shall be judged acceptable at the end of inspection.