General Machining Standards

The following minimum specifications for dimensions and features of manufacturing apply to all parts processed or controlled (through sub suppliers) when customer specifications do not define requirements.


  • Decimal diameters plus or minus .005”; decimal lengths plus or minus .015”
  • Fractional diameters plus or minus .010”; fractional lengths plus or minus .020”
  • Angular plus or minus 2 degrees

Intersecting Surfaces (Corners, Counterbores):

  • Fillets .030” Max
  • Corners .030” Max. Radius or Chamfer

Finishes (Unspecified):

  • Not to exceed 150 micro-inches (Ra, AA or RMS)

Threads General:

  • The inspection gages will conform to the limits specified in the latest applicable ANSI Standard
  • Unless otherwise specified, threads will be of the American national or Unified form and will be made to Class 2A or Class 2B fit tolerances
  • Dimensions on drawing requiring full thread length or minimum full thread shall be measured to the center of the full root appearing behind the last full thread
  • All threads must be free from torn edges; wiry and burr conditions are unacceptable

External Threads:

  • Where threading to the shoulder is specified, it shall be understood that the last full thread will not be cut closer than the distance of two and one-half threads

Internal Threads:

  • The percent of full thread shall be in accordance with regularly accepted general practices
  • Blind tapped holes may not have a full thread closer than five threads from the bottom, and in the case of fine pitches, not closer than 5/32”


  • The orientation of milling, drilling, etc., operations will be without regard or relation to other characteristics unless specified on the drawing


  • No hanging burrs or sharp corners are acceptable unless a measured or specified sharp corner is a specified feature of the drawing

Plating Allowances: 

  • Allowances shall be made to control plans or process drawings issued to the production floor to allow for specified plating requirements as necessary