T.O. 1-1A-9
TABLE 3-18. GENERAL ALUIIINUM RIVET SELECTION CART (RIVET ALLOY VS ASSEMBLY ALLOY)
Rivet Alloy
Assembly Alloy
1100
1100, 3003, 3004, 5052
2117-T4 (AD)
3003. H16 and H-18, 5052. H16
and H18, 2014, 2017 2021, 6061
7075, and 7178.
2017-T4(D), 2024TL (DD)
2014, 2017, 202h, 5052, 6061
7075 and 7178
5056-1132(B)
5052 and magnesium alloys, AZ31B, etc.
a.
Spraying holes with primer after drilling and immediately preceding installation of rivet.
b.
Dipping rivet in zinc chromate primer and installing while still wet.
3-174. For additional information on rivets (strengths, factors, etc.) see MIL-HDBK-5, T.O.'s 1-1A-8 and 1-1A-1.
3-175. MACHINING. The resistance encountered in cutting aluminum alloys is low in comparison to other metals. In
fact most of the aluminum alloys will machine approximately 10 times faster than steel. This factor combined with other
properties, i.e., strength, heat treatability, weight, corrosion resistance, etc. makes aluminum a preferred material in
many instances for fabrication of parts by machining. Brass (free machining) is the only other material with comparable
machining properties.
3-176. Personnel accomplishing the work should be properly trained in machining aluminum as with other types of
metals. Due to various circumstances personnel familiar with machining steel products are required to machine
aluminum without proper training/information on speeds, feeds, tools etc., required to effectively accomplish a specific
task. The purpose of this section is to provide a general guide for selection of tools, machining, speeds, etc.
3-177. The tools used for machining aluminum will normally require more rake side-top and operation at higher/feeds
than used for steel. The amount of rake required will depend on composition, physical form (cast or wrought) and
temper. The more ductile or softer the alloy the more rake required. The following general practices are recommended
for shafing, grinding and maintaining tools for cutting aluminum:
1.
Allow more space for chips to be formed andexpelled from tool than allowed for steel.
2.
Design tools (grind tool) so that chips and cuttings are expelled away from the work piece.
3.
Keep cutting edges of tools sharp, smooth, free of burrs, wire edges and scratches.
4.
Use high machining speeds, moderate feeds and depths of cut.
5.
Apply lubricant/coolant in large quantities to tool when cutting.
3-178. The higher speeds utilized for machining aluminum requires:
1.
Machines be free of vibration and lost motion.
2.
Rigid support of tool near cutting edge to minimize clatter and vibration.
3.
Secure clamping of work to machine to avoid distortion or slippage.
4.
Use of proper lubricant, cutting compound or coolants to prevent overheating, warpage/distortion and to
provide adequate lubrication to cutting tool.
3-179. CUTTING TOOLS FOR MACHINING ALUMINUM . There are four general types of tool steel material that can
be used to machine aluminum. They should be selected in accordance with availability and scope of job to be
accomplished. The following is a suggested guide for selection of tools:
a.
High carbon tool steel is adequate for machining a small number of parts or where cutting speed required is
relatively low.
3-41
