Leach 2R-III - Capscrew Marking and Torque Values

General Repair Practices 39
Capscrew Marking and Torque Values
Usage Much Used Used at Times Used at Times
Capscrew Diameter To
3
4 - 120,000 To
5
8 - 140,000 150,000
& Minimum Tensile To 1 - 115,000 To
3
4 - 133,000
Strength PSI
Quality of Material Min. Commercial Med. Commercial Best Commercial
SAE Grade Number 5 6 or 7 8
CAPSCREW HEAD MARKINGS
Manufacturer
s marks may var y .
These are all SAE Grade 5 (3-line.)
Capscre w Bod y Size Torque Torque Torque
(Inches) - (Thread) Ft-Lb (kg m) Ft-Lb (kg m) Ft-Lb (kg m)
1
4 - 20 8 (1.11) 10 (1.38) 12 (1.66)
- 28 10 (1.38) 14 (1.94)
5
16 - 18 17 (2.35) 19 (2.63) 24 (3.32)
- 24 19 (2.63) 27 (3.73)
3
8 - 16 31 (4.29) 34 (4.70) 44 (6.09)
- 24 35 (4.84) 49 (6.78)
7
16 - 14 49 (6.78) 55 (7.61) 70 (9.68)
- 20 55 (7.61) 78 (10.79)
1
2 - 13 75 (10.37) 85 (11.76) 105 (14.52)
- 20 85 (11.76) 120 (16.60)
9
16 - 12 110 (15.21) 120 (16.60) 155 (21.44)
- 18 120 (16.60) 170 (23.51)
5
8 - 11 150 (20.75) 167 (23.10) 210 (29.04)
- 18 170 (23.51) 240 (33.19)
3
4 - 10 270 (37.34) 280 (38.72) 375 (51.86)
- 16 295 (40.80) 420 (58.09)
7
8 - 9 395 (54.63) 440 (60.85) 605 (83.67)
- 14 435 (60.16) 675 (93.35)
1 - 8 590 (81.60) 660 (91.28) 910 (125.85)
- 14 660 (91.28) 990 (136.92)
NOTES:
1. Always use the torque values listed above when specific torque values are not available.
2. The above is based on use of clean, dry threads.
3. Reduce torque by 10% when engine oil is used as a lubricant.
4. Reduce torque by 20% if new plated capscrews are used.
5. General Formula for calculating Torques is as follows: Torque in Inch Lbs. = .2 x Nominal Diameter of Screw x
Loads in Lbs., where Load = 80% of Yield Strength, expressed in Lbs., not pounds per square inch.
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