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Hex-Head Flange Bolts — 3/8"-16 x 3/4" Grade 8, Black Phosphate, Box
- Mfg.#
- 43187-b
- Sku#
- 6334031
- Pack of six Grade 8 hex-head flange bolts designed for heavy-duty fastening
- Size 3/8"-16 x 3/4" suitable for use with matching 3/8"-16 threaded holes
- Features steel construction designed for high strength and durability
- Features Grade 8 black phosphate finish suitable for improved surface protection
- Hex-head flange design provides built-in flange for wider load distribution
* Estimated stock levels as of Fri, Apr 10, 2026. All items subject to prior sale. Prices may vary between stores and online. Please call ahead to confirm availability of items marked as Limited Stock.
Description
Grade 8 hex-head flange bolts from HILLMAN are heavy-duty fasteners made from steel with a black phosphate finish, built for applications where high strength and corrosion-resistant surface treatment matter. The 3/8"-16 x 3/4" size with a 3/8" diameter and 0.8" flange provides a large bearing surface to distribute load and resist loosening without a separate washer. These hex-head flange bolts are suited for demanding fastening jobs in machinery, metal framing, equipment repair, and other projects that call for rugged, reliable hardware. The Grade 8 classification signifies a high-strength alloy construction, while the black finish offers a subdued appearance that blends with dark hardware and resists light surface corrosion. Made in TW and carrying HILLMAN quality, they work well wherever a compact, high-strength bolt is required.
Specifications
General
| Class | Grade 8 |
|---|---|
| Color | Black |
| Drive Style | External Hex |
| Finish | Grade 8 Black Phosphate |
| Finish Family | Gray |
| Head Style | Hex Washer |
| Imperial/Metric | Imperial |
| Indoor/Outdoor | Indoor |
| Material | Steel |
| Pack Qty | 6 |
| Point Type | Blunt |
| Thread Type | USS Coarse |
| Thread per Inch | 16 |
| Type | Flange Bolts |
Dimensions
| Diameter | 3/8" |
|---|---|
| Length | 3/4 in |
| Size | 3/8"-16 x 3/4" |
| Weight | 0.05 |
| Width | 0.8 |
Manufacturing Details
The following information is subject to change without notice
| Country of Origin | TW |
|---|---|
| Prop 65 Warning |
WARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov
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