Boss - Plug/Pin, Expansion Type Hole Preparation AIR3276

DOI: https://doi.org/10.4271/AIR3276

Issuing Committee: E-25 General Standards for Aerospace and Propulsion Systems

Publisher: SAE International

Pages: 2

Rationale: AIR3276 has been reaffirmed to comply with the SAE five-year review policy. 1 MINIMUM WALL THICKNESS, DIMENSION B, IS REQUIRED TO PRODUCE THE PROOF PRESSURE SPECIFIED IN COLUMN E. 2 DIMENSIONS SPECIFIED IN COLUMN B PROVIDE STRESSES AT THE OUTSIDE OF THE BOSS WHICH WILL NOT EXCEED 20,000 PSI FOR ALUMINUM PLUGS IN ALUMINUM BOSSES OR 46,100 PSI FOR 416 CRES PLUGS IN 416 CRES BOSSES (26–32 HRC). 3 DIAMETER A TOLERANCE CLASS SELECTION IS BASED ON PLUG LENGTH PROOF PRESSURE REQUIREMENTS. 4 THE SHOULDER PRODUCED BY C DIAMETER AND THE 45° CHAMFER IS REQUIRED TO SUPPORT THE PLUG WHILE DRIVING THE PIN. VARIATIONS IN THESE FEATURES MAY ALLOW THE PLUG TO MOVE DOWN THE BORE UPON DRIVING THE PIN WHICH CAN CAUSE REDUCED PROOF PRESSURES. 5 PROOF PRESSURES INDICATED ARE FOR 2024-T4 ALUMINUM PLUGS IN 2024-T4 ALUMINUM BOSSES, 303 CRES PLUGS IN 303 CRES BOSSES, AND 416 CRES PLUGS IN 416 CRES BOSSES (26–32 HRC) 6 DIAMETER "A" IS .010 OVERSIZE FOR REPAIR PLUG. 7 SURFACE TEXTURE: SYMBOLS PER ANSI Y14.36-1978, REQUIREMENTS PER ANSI B46.1-1978. 8 DIMENSIONING AND TOLERANCING: ANSI Y14.5-1973. 9 DIMENSIONS IN INCHES UNLESS OTHERWISE SPECIFIED. DIMENSIONS APPLY AFTER FINISH.