Hex Cap Screw ASME B18.2.1
ASME B18.2.1 (Current)
- Material
- Carbon Steel
- Property Class
- Grade 5, Grade 8
- Finish
- Zinc Plated, Blackened, Plain
- Size range
- 1/4-20UNC–7/8-9UNC
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Select sizes and quantities — 147 confirmed sizes to ASME B18.2.1
Material
Grade
Finish
| dNominal Diameter (in) | lLength (in) | sWidth Across Flats (max) (in) | eWidth Across Corners (min) (in) | kNominal Head Height (in) | dBasic Major Diameter (in) | MOQ | Quantity and inquiry |
|---|---|---|---|---|---|---|---|
| 3/8-16 UNC | 3.5 | 0.562 | 0.628 | 0.243 | 0.375 | 1000 | |
| 3/8-16 UNC | 3.75 | 0.562 | 0.628 | 0.243 | 0.375 | 1000 | |
| 3/8-16 UNC | 4 | 0.562 | 0.628 | 0.243 | 0.375 | 1000 | |
| 3/8-16 UNC | 4.5 | 0.562 | 0.628 | 0.243 | 0.375 | 1000 | |
| 3/8-16 UNC | 5 | 0.562 | 0.628 | 0.243 | 0.375 | 1000 | |
| 7/16-14 UNC | 0.875 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 | |
| 7/16-14 UNC | 1 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 | |
| 7/16-14 UNC | 1.125 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 | |
| 7/16-14 UNC | 1.25 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 | |
| 7/16-14 UNC | 1.375 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 | |
| 7/16-14 UNC | 1.5 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 | |
| 7/16-14 UNC | 1.75 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 | |
| 7/16-14 UNC | 2 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 | |
| 7/16-14 UNC | 2.25 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 | |
| 7/16-14 UNC | 2.5 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 | |
| 7/16-14 UNC | 2.75 | 0.625 | 0.698 | 0.291 | 0.4375 | 500 |
Showing 16 of 147 sizes
dNominal Diameter (in)3/8-16 UNC
lLength (in)3.5
sWidth Across Flats (max) (in)0.562
eWidth Across Corners (min) (in)0.628
kNominal Head Height (in)0.243
dBasic Major Diameter (in)0.375
MOQ1000
3/8-16 UNC × 3.75 × 0.562 × 0.628 × 0.243 × 0.375 × 16 × UNC × 2A × 0.375 × 0.369 × 0.551 × 0.65 × 0.226 × 0.16 × 1 × 1.25
dNominal Diameter (in)3/8-16 UNC
lLength (in)3.75
sWidth Across Flats (max) (in)0.562
eWidth Across Corners (min) (in)0.628
kNominal Head Height (in)0.243
dBasic Major Diameter (in)0.375
MOQ1000
3/8-16 UNC × 4 × 0.562 × 0.628 × 0.243 × 0.375 × 16 × UNC × 2A × 0.375 × 0.369 × 0.551 × 0.65 × 0.226 × 0.16 × 1 × 1.25
dNominal Diameter (in)3/8-16 UNC
lLength (in)4
sWidth Across Flats (max) (in)0.562
eWidth Across Corners (min) (in)0.628
kNominal Head Height (in)0.243
dBasic Major Diameter (in)0.375
MOQ1000
3/8-16 UNC × 4.5 × 0.562 × 0.628 × 0.243 × 0.375 × 16 × UNC × 2A × 0.375 × 0.369 × 0.551 × 0.65 × 0.226 × 0.16 × 1 × 1.25
dNominal Diameter (in)3/8-16 UNC
lLength (in)4.5
sWidth Across Flats (max) (in)0.562
eWidth Across Corners (min) (in)0.628
kNominal Head Height (in)0.243
dBasic Major Diameter (in)0.375
MOQ1000
3/8-16 UNC × 5 × 0.562 × 0.628 × 0.243 × 0.375 × 16 × UNC × 2A × 0.375 × 0.369 × 0.551 × 0.65 × 0.226 × 0.16 × 1 × 1.25
dNominal Diameter (in)3/8-16 UNC
lLength (in)5
sWidth Across Flats (max) (in)0.562
eWidth Across Corners (min) (in)0.628
kNominal Head Height (in)0.243
dBasic Major Diameter (in)0.375
MOQ1000
7/16-14 UNC × 0.875 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)0.875
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
7/16-14 UNC × 1 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)1
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
7/16-14 UNC × 1.125 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)1.125
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
7/16-14 UNC × 1.25 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)1.25
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
7/16-14 UNC × 1.375 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)1.375
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
7/16-14 UNC × 1.5 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)1.5
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
7/16-14 UNC × 1.75 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)1.75
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
7/16-14 UNC × 2 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)2
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
7/16-14 UNC × 2.25 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)2.25
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
7/16-14 UNC × 2.5 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)2.5
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
7/16-14 UNC × 2.75 × 0.625 × 0.698 × 0.291 × 0.4375 × 14 × UNC × 2A × 0.4375 × 0.4305 × 0.612 × 0.722 × 0.272 × 0.195 × 1.125 × 1.375
dNominal Diameter (in)7/16-14 UNC
lLength (in)2.75
sWidth Across Flats (max) (in)0.625
eWidth Across Corners (min) (in)0.698
kNominal Head Height (in)0.291
dBasic Major Diameter (in)0.4375
MOQ500
Product details
- Description
- Hex cap screw manufactured to ASME B18.2.1 with a hexagon head and partially threaded shank. The thread is UNC class 2A, and the unthreaded body length depends on the nominal diameter. Available in carbon steel, Grade 5 or Grade 8, with zinc plated, blackened, or plain finish. Diameters from 1/4-20 UNC to 1-8 UNC are listed. For quotation, specify diameter, thread series, length, grade, and finish.
- Features
- Hexagon head for standard spanners and sockets · Partially threaded shank with plain bearing section under the head · UNC thread class 2A · Available in diameters 1/4-20 UNC through 1-8 UNC
- Applications
- Shear-loaded joints where a plain shank is required, Steel structure connections, Machinery and equipment assembly, Maintenance and repair work
Order assurance
Confirmed for the quoted product and order.Reports & inspection
Agreed in the quotation.
- EN 10204 3.1 material certificate
- Dimensional inspection report
- Certificate of conformity
- Mechanical test report
- Chemical analysis report
- Coating inspection report
- Batch and lot traceability
Packaging & delivery
Options we supply.
- Bulk carton packing
- Small boxes with outer cartons
- Palletized shipment
- Fumigation-free pallets
- Inner poly bags
- Buyer branding and labels
Product questions
What sizes of Hex Cap Screw ASME B18.2.1 do you supply?
Execution standard: ASME B18.2.1. The confirmed specification table covers 1–7 diameters and 0.5–5.5 lengths. Use the specification table to select the exact variant required for quotation.
Which materials, grades and finishes can I order?
Material: Carbon Steel; Property class: Grade 5, Grade 8; Finish: Zinc Plated, Blackened, Plain. Availability should be confirmed against the selected specification and order quantity.
Where are these hex bolts typically used?
Typical applications include Shear-loaded joints where a plain shank is required, Steel structure connections, Machinery and equipment assembly, Maintenance and repair work. Final suitability depends on the selected material, grade, finish and operating conditions.







