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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.

Dimensions:

 

  • 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”

Orientation:

 

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

Burrs:

 

  • 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