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Hex-Head Flange Bolts — 3/8 in. Diameter x 1-1/4 in. Length, 4-Pack
- Mfg.#
- 43189-d
- Sku#
- 6334056
- Designed for heavy-duty fastening with Grade 8 strength for high-tensile applications
- Features hex head with integrated flange to distribute load and eliminate separate washers
- Suitable for 3/8"-16 x 1-1/4" applications where standard USS coarse threads are required
- Finished in black phosphate and presented in a black color for basic corrosion resistance
* Estimated stock levels as of Sun, May 24, 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
These are Grade 8 hex-head flange bolts from HILLMAN, designed for tough fastening tasks where strength and corrosion-resistant finish matter. Offered in 3/8"-16 x 1-1/4" size, each steel bolt features a hex head with integral flange and a black phosphate finish for a uniform black appearance and added surface protection. Use them where a secure, vibration-resistant hold is needed—assembling metal frames, mounting hardware to structural members, or replacing worn fasteners on machinery and outdoor equipment. The flange spreads load to reduce the need for a washer and speeds installation with a standard wrench or socket. Made in Taiwan and supplied in a convenient 4-pack, these bolts are a solid choice for automotive repairs, farm equipment maintenance, and heavy-duty DIY projects that call for Grade 8 strength and dependable, long-lasting performance.
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 | 4 |
| Point Type | Blunt |
| Thread Type | USS Coarse |
| Thread per Inch | 16 |
| Type | Flange Bolts |
Dimensions
| Diameter | 3/8" |
|---|---|
| Length | 1-1/4 in |
| Size | 3/8"-16 x 1-1/4" |
| Weight | 0.07 |
| 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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