Specifications include, but are not limited to: 1. Cutting edges shall be of four types: flat drag blades, curved hardened grader blades, serrated grader blades (hardened), and flat carbide insert blades. Any variation in these requirements shall be noted under the various descriptions. 2. Blade thickness tolerances shall be –0.020” and +0.040” 3. Blade length tolerances shall be +0.000” and –0.125” 4. Hole spacing dimensional tolerances shall be 0.0625” non-accumulative as shown in the illustrated attached Drawing A. 5. 11/16” (0.688”) Countersunk square holes shall meet the requirements of SAE standard J740 for 5/8”, No. 3 Head-Plow bolts. Drawing A 6. Camber tolerances: Maximum camber shall not exceed 1/8” for all lengths 0.0 ft through 6.0 ft, 3/16” for all lengths over 6.0 ft. through 10.0 ft. and 1/4” for all lengths over 10.0 ft. 7. Blade ends shall be square and cleanly cut. 8. Blades shall be free from injurious defects. 9. Blade faces shall be clean and free from pits, loose mil scale and rust. 10. Coating: Each blade shall be given one coat of rust resistant paint. 11. Mill test reports (original) shall accompany each blade shipment and shall include all chemical and physical test analysis of each heat number and shall be certified and signed by the producing mill. 12. Each blade shall be uniform in thickness and in width. 13. All grader and serrated blades must be packaged in bundles with the concave faces down so moisture will not be accumulated and be retained in the curvature. 14. Sampling and Testing: A minimum of three (3) samples shall be secured and tested at random by the Iowa Department of Transportation.
