Applies to manufacturers of parts for arms, aircraft or similar apparatus. 

Shall not be assigned to an employer engaged in operations described by another  classification unless the operations subject to Code 3629 are conducted as a separate and distinct business.

Code 3629 applies to employers engaged in manufacturing precision machined parts.  Since many employers engaged in the manufacturing of precision machined parts also perform general job machining operations, more than 50% of the parts machined must be held to final tolerance of .001 or closer to qualify for this classification.

Raw materials handled may consist of iron, stainless steel, steel, aluminum, bronze, brass, copper, titanium or nickel in the form of bars, rods, plates, rounds, tubes, blocks, castings, forgings, angles or rings.  In production, using manual semi-automatically controlled machines, the materials are cut to size, milled, turned, ground, drilled, and tapped in accordance with the blueprint specifications provided by the customer.