Grade 5 bolt torque chart and strength

A 1/2-13 Grade 5 bolt takes 75 ft-lb plain and dry, 68 ft-lb zinc-plated or 57 ft-lb oiled, with 9,050 lbf of clamp load. Grade 5 has 85 ksi proof strength up to 1 in and three radial lines on the head.

By the Torque Reference editors 5 sources cited Last reviewed 21 Oct 2026 Method

Contents9 sections

Key takeaways

Grade 5 is medium carbon steel, quenched and tempered ⁠¹.
Three radial lines, 120° apart, mark the head ⁠¹.
Proof stress is 85 ksi to 1 in, then 74 ksi from over 1 in to 1-1/2 in ⁠¹.
Grade 8 takes about 41% more torque than Grade 5. Grade 2 takes about 35% less up to 3/4 in.

Quick facts

Material	Medium carbon steel, quenched and tempered ⁠¹
Head marking	3 radial lines
Proof, 1/4–1 in	85,000 psi
Metric near-equivalent	Class 8.8

Grade 5 strength

Sizes	Proof stress	Yield	Tensile
1/4 to 1 in	85,000 psi	92,000 psi	120,000 psi
Over 1 to 1-1/2 in	74,000 psi	81,000 psi	105,000 psi

Sizes

Proof stress

Yield

Tensile

1/4 to 1 in

85,000 psi

92,000 psi

120,000 psi

Over 1 to 1-1/2 in

74,000 psi

81,000 psi

105,000 psi

SAE J429 values as tabulated by Fastenal⁠¹.

Grade 5 torque chart

Size	Dry K 0.20⁠¹	Zinc K 0.18⁠¹	Oiled K 0.15⁠¹
1/4-20	101 in-lb11 N·m	91 in-lb10 N·m	76 in-lb8.6 N·m
5/16-18	17 ft-lb24 N·m	16 ft-lb21 N·m	13 ft-lb18 N·m
3/8-16	31 ft-lb42 N·m	28 ft-lb38 N·m	23 ft-lb31 N·m
7/16-14	49 ft-lb67 N·m	44 ft-lb60 N·m	37 ft-lb50 N·m
1/2-13	75 ft-lb102 N·m	68 ft-lb92 N·m	57 ft-lb77 N·m
9/16-12	109 ft-lb147 N·m	98 ft-lb133 N·m	82 ft-lb111 N·m
5/8-11	150 ft-lb203 N·m	135 ft-lb183 N·m	113 ft-lb153 N·m
3/4-10	267 ft-lb362 N·m	240 ft-lb326 N·m	200 ft-lb271 N·m
7/8-9	430 ft-lb582 N·m	387 ft-lb524 N·m	322 ft-lb437 N·m
1-8	644 ft-lb873 N·m	579 ft-lb786 N·m	483 ft-lb655 N·m

Size

Dry K 0.20⁠¹

Zinc K 0.18⁠¹

Oiled K 0.15⁠¹

1/4-20

101 in-lb11 N·m

91 in-lb10 N·m

76 in-lb8.6 N·m

5/16-18

17 ft-lb24 N·m

16 ft-lb21 N·m

13 ft-lb18 N·m

3/8-16

31 ft-lb42 N·m

28 ft-lb38 N·m

23 ft-lb31 N·m

7/16-14

49 ft-lb67 N·m

44 ft-lb60 N·m

37 ft-lb50 N·m

1/2-13

75 ft-lb102 N·m

68 ft-lb92 N·m

57 ft-lb77 N·m

9/16-12

109 ft-lb147 N·m

98 ft-lb133 N·m

82 ft-lb111 N·m

5/8-11

150 ft-lb203 N·m

135 ft-lb183 N·m

113 ft-lb153 N·m

3/4-10

267 ft-lb362 N·m

240 ft-lb326 N·m

200 ft-lb271 N·m

7/8-9

430 ft-lb582 N·m

387 ft-lb524 N·m

322 ft-lb437 N·m

1-8

644 ft-lb873 N·m

579 ft-lb786 N·m

483 ft-lb655 N·m

Calculated with T = K × D × F, where F is 75% of the bolt’s proof load⁠¹ and K is the nut factor for each condition. Real preload from a torque wrench scatters by about ±25%⁠². When the equipment maker gives a torque, use theirs. How these numbers are made.

Material and marking

SAE J429 Grade 5 is medium carbon steel, quenched and tempered. Core hardness is Rockwell C25–C34 up to 1 in and C19–C30 for larger sizes ⁠¹. The head carries three radial lines 120° apart ⁠¹.

Strength breaks

Grade 5 has two strength levels ⁠¹:

1/4 to 1 in: 85 ksi proof, 92 ksi yield, 120 ksi tensile.
Over 1 to 1-1/2 in: 74 ksi proof, 81 ksi yield, 105 ksi tensile.

Every size on this site’s chart (1/4 to 1 in) falls in the first range. Above 1 in, proof drops 13%, so a torque scaled up from the 1 in value would overshoot by the same amount. The 1-8 Grade 5 value is 644 ft-lb dry.

Compared with other grades

Torque scales with proof stress at the same size and condition:

Grade 8: 120 ÷ 85, or about 41% more in every size. At 1/2-13 that is 107 ft-lb dry against 75.
Grade 2: about 35% less from 1/4 to 3/4 in. At 7/8 and 1 in, Grade 2’s proof falls to 33 ksi, so Grade 5 needs 2.6 times the Grade 2 torque.
Metric class 8.8: almost the same strength. Grade 5’s 85 ksi is 586 MPa, against 580 MPa for 8.8 up to M16 ⁠³.

Grade 5 also matches the structural A325 bolt (ASTM F3125 Grade A325) on paper: 120 ksi tensile and 85 ksi proof ⁠⁴. The two are still not interchangeable. A325 is a heavy hex bolt installed to RCSC pretension rules, and RCSC does not allow table torque for those joints ⁠⁵. See structural bolt vs Grade 5 and 8.

Matching nut

Use an SAE J995 Grade 5 nut. Grade 8 may substitute ⁠¹. The Grade 5 nut’s proof stress is 120 ksi on UNC threads and 109 ksi on UNF up to 1 in ⁠¹. On coarse threads, that equals the bolt’s 120 ksi tensile strength, which is what the nut selection rule asks for.

Picking the condition

The condition column matters as much as the grade. For a 1/2-13 bolt, 75 ft-lb dry, 68 ft-lb zinc and 57 ft-lb oiled all give the same 9,050 lbf clamp load. Each uses its own nut factor, 0.20, 0.18 and 0.15 ⁠¹. Using the dry value on an oiled bolt asks for about 33% more tension than intended. For anti-seize or moly, see the lubricated torque calculator.

Sources

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