USAF General Purpose Eddy Current Standard Test Block 4340 Steel       

The Air Force general purpose eddy current standard (Figure 4-55, Sheet 1 through Figure 4-55, Sheet 3) SHALL be the common standard used to perform ET’s on components within the Air Force. The standard made to the Navy configuration (Figure 4-56) may be used as a substitute for the Air Force general purpose eddy current standard. When using the Navy standard, calibrate on the long EDM notches for surface inspections and the corner notches in the upper layers for bolt hole inspections unless otherwise directed by a part specific procedure. Manufactured IAW U.S.A.F. Tech Order 33B-1-1, Figure 4-39. NSN 6635-01-092-5129 and P/N 7947479-10.

U.S. Air Force General Purpose Eddy Current Standard. A (3) plate assembly containing (20) fastener holes with a total of (66) EDM notches in various locations.

• Overall Dimensions: 1.06" thick x 4.0" wide x 7.0" long.

• (20) Fastener Holes from .156 to .750" diameter.

• (40) Corner notches, (20) Bore notches, (4) Surface notches (1) Tapered notch, (1) Radius notch.

• All EDM notches are .004 ± .001 wide.

• Finished standard is anodized per MIL-A-8625.

• Manufactured IAW U.S.A.F. Tech Order 33B-1-1, Figure 4-39.

• NSN 6635-01-092-5129 and P/N 7947479-10

• Material: 4340 Steel