Fasteners_05_Examples

Screening of Critical and Flight Hardware and Ground Support Equipment
Fastener Type Visual Tensile 100% NDE 100% Hardness 100% Dimensional Locking/breakaway torques (4) 100% Proof test Dimensional Hardness
Bolt, single point failure/safe life (3) X X(2) X(2) X(2) X   O(2)    
Nut, single point failure/fail safe, #10 (5mm) and larger X       X X(4) X    
Bolt or nut, redundant load path/fail safe, #10 (5mm) and larger X X(5)       X(4)   X O(5)
Bolt or nut, redundant load path/fail safe, #8 (4mm) and smaller X             X  
Rivet, Shear pin X             X X(6)
Helical insert, Cylindrical insert, Setscrews X             X  

X - required testing, O - optional test method, may be substituted for other test methods, see notes.

Galvanic Corrosion

The further apart the following are in the list, the greater the galvanic corrosion

  1. Magnesium (most active)
  2. Magnesium alloys
  3. Zinc
  4. Aluminum 5056
  5. Aluminum 5052
  6. Aluminum 1100
  7. Cadmium
  8. Aluminum 2024
  9. Aluminum 7075
  10. Mild steel
  11. Cast iron
  12. Ni-Resist
  13. Type 410 stainless (active)
  14. Type 304 stainless (active)
  15. Type 316 stainless (active)
  16. Lead
  17. Tin
  18. Muntz metal
  19. Nickel (active)
  20. Inconel (active)
  21. Yellow brass
  22. Admiralty brass
  23. Aluminum brass
  24. Red brass
  25. Copper
  26. Silicon bronze
  27. 70-30 Copper-nickel
  28. Nickel (passive)
  29. Inconel (passive)
  30. Titanium
  31. Monel
  32. Type 304 stainless (passive)
  33. Type 316 stainless (passive)
  34. Silver
  35. Graphite
  36. Gold (least active)

Torque Table

No lubrication on threads. Torque values are based on friction coefficients of 0.12 between threads and 0.14 between nut and washer or head and washer, as manufactured (no special cleaning).

Size Root area, in.2 Torque range (class 8, 150 ksi, bolts)
10-24 0.0145 23 to 34 in.-lb
10-32 0.0175 29 to 43 in.-lb
1/4-20 0.0269 54 to 81 in.-lb
1/4-4-28 0.0326 68 to 102 in.-lb
5/16-18 0.0454 117 to 176 in.-lb
5/16-24 0.0524 139 to 208 in.-lb
3/8-16 0.0678 205 to 308 in.-lb
3/8-24 0.0809 230 to 345 in.-lb
7/16-14 0.0903 28 to 42 in.-lb
7/16-20 0.1090 33 to 50 in.-lb
1/2-13 0.1257 42 to 64 in.-lb
1/2-20 0.1486 52 to 77 in.-lb
9/16-12 0.1620 61 to 91 in.-lb
9/16-18 0.1888 73 to 109 in.-lb
5/8-11 0.2018 84 to 126 in.-lb
5/8-18 0.2400 104 to 156 in.-lb
3/4-10 0.3020 117 to 176 in.-lb
3/4-16 0.3513 139 to 208 in.-lb
7/8-9 0.4193 184 to 276 in.-lb
7/8-14 0.4805 213 to 320 in.-lb
1-8 0.5510 276 to 414 in.-lb
1-14 0.6464 323 to 485 in.-lb
1 1/8-7 0.6931 390 to 585 in.-lb
1 1/8-12 0.8118 465 to 698 in.-lb
1 1/4-7 0.8898 559 to 838 in.-lb
1 1/4-12 1.0238 655 to 982 in.-lb

Screening of Critical and Flight Hardware and Ground Support Equipment Notes
  1. Inspections/tests are on a lot sampling basis unless otherwise indicated
  2. Proof testing is an acceptable substitute for tensile, NDE, and hardness
  3. Usage shall be #10 (5mm) or larger. Use of size #8 (4mm) or smaller shall be approved by the Project’s Lead Mechanical Engineer
  4. Self-locking nuts, nutplates and Hi-Lok/Hi-Tigue collars only
  5. Acceptable to substitute hardness testing on bolts or screws if they are too short to tensile test (when the length is less than 4 times the diameter) or on fail safe or redundant load path nuts.
  6. Hardness test waived on <3/16" (5mm) diameter and on all blind rivets.