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 |
|---|---|---|---|---|---|---|---|
| 3/4-10 UNC | 2.5 | 1.125 | 1.254 | 0.483 | 0.75 | 250 | |
| 3/4-10 UNC | 2.75 | 1.125 | 1.254 | 0.483 | 0.75 | 250 | |
| 3/4-10 UNC | 3 | 1.125 | 1.254 | 0.483 | 0.75 | 250 | |
| 3/4-10 UNC | 3.25 | 1.125 | 1.254 | 0.483 | 0.75 | 250 | |
| 3/4-10 UNC | 3.5 | 1.125 | 1.254 | 0.483 | 0.75 | 250 | |
| 3/4-10 UNC | 3.75 | 1.125 | 1.254 | 0.483 | 0.75 | 250 | |
| 3/4-10 UNC | 4 | 1.125 | 1.254 | 0.483 | 0.75 | 250 | |
| 3/4-10 UNC | 4.5 | 1.125 | 1.254 | 0.483 | 0.75 | 250 | |
| 3/4-10 UNC | 5 | 1.125 | 1.254 | 0.483 | 0.75 | 250 | |
| 3/4-10 UNC | 5.5 | 1.125 | 1.254 | 0.483 | 0.75 | 250 | |
| 7/8-9 UNC | 1.75 | 1.312 | 1.465 | 0.563 | 0.875 | 100 | |
| 7/8-9 UNC | 2 | 1.312 | 1.465 | 0.563 | 0.875 | 100 | |
| 7/8-9 UNC | 2.25 | 1.312 | 1.465 | 0.563 | 0.875 | 100 | |
| 7/8-9 UNC | 2.5 | 1.312 | 1.465 | 0.563 | 0.875 | 100 | |
| 7/8-9 UNC | 2.75 | 1.312 | 1.465 | 0.563 | 0.875 | 100 | |
| 7/8-9 UNC | 3 | 1.312 | 1.465 | 0.563 | 0.875 | 100 |
Showing 16 of 147 sizes
dNominal Diameter (in)3/4-10 UNC
lLength (in)2.5
sWidth Across Flats (max) (in)1.125
eWidth Across Corners (min) (in)1.254
kNominal Head Height (in)0.483
dBasic Major Diameter (in)0.75
MOQ250
3/4-10 UNC × 2.75 × 1.125 × 1.254 × 0.483 × 0.75 × 10 × UNC × 2A × 0.75 × 0.741 × 1.1 × 1.299 × 0.455 × 0.324 × 1.75 × 2
dNominal Diameter (in)3/4-10 UNC
lLength (in)2.75
sWidth Across Flats (max) (in)1.125
eWidth Across Corners (min) (in)1.254
kNominal Head Height (in)0.483
dBasic Major Diameter (in)0.75
MOQ250
3/4-10 UNC × 3 × 1.125 × 1.254 × 0.483 × 0.75 × 10 × UNC × 2A × 0.75 × 0.741 × 1.1 × 1.299 × 0.455 × 0.324 × 1.75 × 2
dNominal Diameter (in)3/4-10 UNC
lLength (in)3
sWidth Across Flats (max) (in)1.125
eWidth Across Corners (min) (in)1.254
kNominal Head Height (in)0.483
dBasic Major Diameter (in)0.75
MOQ250
3/4-10 UNC × 3.25 × 1.125 × 1.254 × 0.483 × 0.75 × 10 × UNC × 2A × 0.75 × 0.741 × 1.1 × 1.299 × 0.455 × 0.324 × 1.75 × 2
dNominal Diameter (in)3/4-10 UNC
lLength (in)3.25
sWidth Across Flats (max) (in)1.125
eWidth Across Corners (min) (in)1.254
kNominal Head Height (in)0.483
dBasic Major Diameter (in)0.75
MOQ250
3/4-10 UNC × 3.5 × 1.125 × 1.254 × 0.483 × 0.75 × 10 × UNC × 2A × 0.75 × 0.741 × 1.1 × 1.299 × 0.455 × 0.324 × 1.75 × 2
dNominal Diameter (in)3/4-10 UNC
lLength (in)3.5
sWidth Across Flats (max) (in)1.125
eWidth Across Corners (min) (in)1.254
kNominal Head Height (in)0.483
dBasic Major Diameter (in)0.75
MOQ250
3/4-10 UNC × 3.75 × 1.125 × 1.254 × 0.483 × 0.75 × 10 × UNC × 2A × 0.75 × 0.741 × 1.1 × 1.299 × 0.455 × 0.324 × 1.75 × 2
dNominal Diameter (in)3/4-10 UNC
lLength (in)3.75
sWidth Across Flats (max) (in)1.125
eWidth Across Corners (min) (in)1.254
kNominal Head Height (in)0.483
dBasic Major Diameter (in)0.75
MOQ250
3/4-10 UNC × 4 × 1.125 × 1.254 × 0.483 × 0.75 × 10 × UNC × 2A × 0.75 × 0.741 × 1.1 × 1.299 × 0.455 × 0.324 × 1.75 × 2
dNominal Diameter (in)3/4-10 UNC
lLength (in)4
sWidth Across Flats (max) (in)1.125
eWidth Across Corners (min) (in)1.254
kNominal Head Height (in)0.483
dBasic Major Diameter (in)0.75
MOQ250
3/4-10 UNC × 4.5 × 1.125 × 1.254 × 0.483 × 0.75 × 10 × UNC × 2A × 0.75 × 0.741 × 1.1 × 1.299 × 0.455 × 0.324 × 1.75 × 2
dNominal Diameter (in)3/4-10 UNC
lLength (in)4.5
sWidth Across Flats (max) (in)1.125
eWidth Across Corners (min) (in)1.254
kNominal Head Height (in)0.483
dBasic Major Diameter (in)0.75
MOQ250
3/4-10 UNC × 5 × 1.125 × 1.254 × 0.483 × 0.75 × 10 × UNC × 2A × 0.75 × 0.741 × 1.1 × 1.299 × 0.455 × 0.324 × 1.75 × 2
dNominal Diameter (in)3/4-10 UNC
lLength (in)5
sWidth Across Flats (max) (in)1.125
eWidth Across Corners (min) (in)1.254
kNominal Head Height (in)0.483
dBasic Major Diameter (in)0.75
MOQ250
3/4-10 UNC × 5.5 × 1.125 × 1.254 × 0.483 × 0.75 × 10 × UNC × 2A × 0.75 × 0.741 × 1.1 × 1.299 × 0.455 × 0.324 × 1.75 × 2
dNominal Diameter (in)3/4-10 UNC
lLength (in)5.5
sWidth Across Flats (max) (in)1.125
eWidth Across Corners (min) (in)1.254
kNominal Head Height (in)0.483
dBasic Major Diameter (in)0.75
MOQ250
7/8-9 UNC × 1.75 × 1.312 × 1.465 × 0.563 × 0.875 × 9 × UNC × 2A × 0.875 × 0.866 × 1.285 × 1.516 × 0.531 × 0.378 × 2 × 2.25
dNominal Diameter (in)7/8-9 UNC
lLength (in)1.75
sWidth Across Flats (max) (in)1.312
eWidth Across Corners (min) (in)1.465
kNominal Head Height (in)0.563
dBasic Major Diameter (in)0.875
MOQ100
7/8-9 UNC × 2 × 1.312 × 1.465 × 0.563 × 0.875 × 9 × UNC × 2A × 0.875 × 0.866 × 1.285 × 1.516 × 0.531 × 0.378 × 2 × 2.25
dNominal Diameter (in)7/8-9 UNC
lLength (in)2
sWidth Across Flats (max) (in)1.312
eWidth Across Corners (min) (in)1.465
kNominal Head Height (in)0.563
dBasic Major Diameter (in)0.875
MOQ100
7/8-9 UNC × 2.25 × 1.312 × 1.465 × 0.563 × 0.875 × 9 × UNC × 2A × 0.875 × 0.866 × 1.285 × 1.516 × 0.531 × 0.378 × 2 × 2.25
dNominal Diameter (in)7/8-9 UNC
lLength (in)2.25
sWidth Across Flats (max) (in)1.312
eWidth Across Corners (min) (in)1.465
kNominal Head Height (in)0.563
dBasic Major Diameter (in)0.875
MOQ100
7/8-9 UNC × 2.5 × 1.312 × 1.465 × 0.563 × 0.875 × 9 × UNC × 2A × 0.875 × 0.866 × 1.285 × 1.516 × 0.531 × 0.378 × 2 × 2.25
dNominal Diameter (in)7/8-9 UNC
lLength (in)2.5
sWidth Across Flats (max) (in)1.312
eWidth Across Corners (min) (in)1.465
kNominal Head Height (in)0.563
dBasic Major Diameter (in)0.875
MOQ100
7/8-9 UNC × 2.75 × 1.312 × 1.465 × 0.563 × 0.875 × 9 × UNC × 2A × 0.875 × 0.866 × 1.285 × 1.516 × 0.531 × 0.378 × 2 × 2.25
dNominal Diameter (in)7/8-9 UNC
lLength (in)2.75
sWidth Across Flats (max) (in)1.312
eWidth Across Corners (min) (in)1.465
kNominal Head Height (in)0.563
dBasic Major Diameter (in)0.875
MOQ100
7/8-9 UNC × 3 × 1.312 × 1.465 × 0.563 × 0.875 × 9 × UNC × 2A × 0.875 × 0.866 × 1.285 × 1.516 × 0.531 × 0.378 × 2 × 2.25
dNominal Diameter (in)7/8-9 UNC
lLength (in)3
sWidth Across Flats (max) (in)1.312
eWidth Across Corners (min) (in)1.465
kNominal Head Height (in)0.563
dBasic Major Diameter (in)0.875
MOQ100
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.







