MIL-STD-866 Grinding Of Chrome Plated Steel And Steel Parts Heat Treated To 180,000 Psi Or OverThis standard establishes the requirements for grinding of martensitic high strength steel heat-treated to 180,000 pounds per square inch psi, ultimate tensile strength uts and above, and the grinding of chromium plating applied to such high strength steel, when such parts are intended for use in components for man-rated flight hardware.

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MIL-STD-866C

vitrified bond are recommended in the largest grit size that will produce the required finish. Hard, dense wheels in fine grit size are most likely to cause problems and their use should be avoided. This same philosophy also applies to coated abrasives.

5.4.3.3 Coolants. Copious quantity should be delivered to the part at the working surface of the grinding wheel. Dry grinding should be avoided whenever possible.

5.4.3.4 Wheel dressing. Wheels should be dressed frequently and before the start of final grinding passes to prevent grinding with a dull or loaded wheel. Dressing should produce a sharp, open wheel.

5.4.3.5 Wheel speed. Excessive wheel speeds may cause overheating and damage to the part and should be avoided.

5.4.3.6 Work speed. Generally, high work speeds are recommended. A rotating wheel (non-traversing) should never contact a stationary part.

finish grinding.

5.4.3.7 Cross-feed. Reduced cross-feed rates are recommended for

5.4.3.8 Down-feed/in-feed. Reduced feed rates and spark-out are recommended for finish grinding. When plunge grinding, allowing each down-feed/in- feed to spark-out, may be beneficial.

5.4.3.9 Grinding with the side of the wheel. Extreme caution should be exercised when grinding with the side of the wheel. Large contact areas and heat input can result. This practice should be avoided if at all possible.

5.4.3.10 Chrome plate. Caution should be exercised when grinding chrome plate since it is possible to cause damage in the substrate. Damage is difficult to detect through the chrome plate.

6. NOTES

(This section contains information of a general or explanatory nature that maybe helpful, but is not mandatory.)

6.1 Intended use. The intent of this document is to establish requirements for controls to prevent overheating, cracking, and other metallurgical change, which decrease structural integrity of parts.

6.2 Subject term (key word) listing.

Grinding Heat-treat Inspection

6.3 Changes from previous issue. Marginal notations are not used in this revision to identify changes with respect to the previous issue due to the extent of the changes.