5/16-18x1-1/4" Hex Cap Screws Grade 5 Bolts Zinc Clear

Product Description

Part Number: 31C125HCS5Z
Diameter/Pitch: 5/16"-18
Grade: Grade 5
Length Under Head: 1-1/4"
Finish: Zinc Clear
Thread Series: Coarse (UNC)
Threading: Fully threaded
Wrench Size: 1/2"

BoltsandNuts.com

5/16-18x1-1/4" Hex Cap Screws Grade 5 Bolts Zinc Clear

SKU: 31C125HCS5Z

Product Description

Part Number: 31C125HCS5Z
Diameter/Pitch: 5/16"-18
Grade: Grade 5
Length Under Head: 1-1/4"
Finish: Zinc Clear
Thread Series: Coarse (UNC)
Threading: Fully threaded
Wrench Size: 1/2"

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Thread Size	5/16"-18
Material	Medium carbon steel, quenched and tempered
Thread Series	Coarse (UNC)
Head Marking	Three radial lines on head
Proof Load (min)	4,460 lbf

Length	1-1/4"
Finish	Zinc Clear
Threading	Fully threaded
Thread Class	2A
Hardness	Rockwell C25–C34

Grade	Grade 5
Wrench Size	1/2"
Head Height	0.195" – 0.211"
Tensile Strength (min)	120,000 psi
Specifications Met	ASME B18.2.1, SAE J429 Grade 5

Technical Drawing

Not to scale · ASME B18.2.1 · See table for exact dimensions

Technical Dimensions

Length Under Head	1-1/4"
Major Thread Dia.	0.312"
Head Height	0.195" – 0.211"
Width Across Flats	0.500" (1/2")
Width Across Corners	0.577" max
Threads Per Inch	18 TPI
Thread Length	Fully threaded
Thread Class	2A
Proof Load	4,460 lbf
Clamp Load	3,340 lbf
Min. Tensile Strength	120,000 psi
Yield Strength	92,000 psi
Hardness	Rockwell C25–C34

Hex cap screw with a hexagonal head for external wrench engagement and a chamfered point for easier starting. The flat bearing surface distributes clamp load across the joint. Fully threaded shank, with unified coarse (UNC) threads.

Dimensions conform to ASME B18.2.1 and may vary within specified manufacturing tolerances.