ASME/ANSI B18.5 (T7):2012 Inch Series Countersunk Head Slotted Bolt is used in inch-series assemblies where a low exposed surface is required and the head may need auxiliary positioning or light adjustment. The slot allows use of a flat-blade tool.
The countersunk head seats into a tapered recess to create a relatively flush surface, making it suitable for wood panels, decorative plates, equipment covers, furniture-style structures, and light mechanical joints. The slot can also help identify head orientation during maintenance.
Countersink angle, slot size, thread series, and surface quality should be controlled. For high-torque applications, tightening should not rely only on the slot; the nut side can be used to manage the main clamping process.

Dimensions unit: mm
| Thread size d | 1/4 | 5/16 | 3/8 | 7/16 | 1/2 | 5/8 | 3/4 | 7/8 | 1 | 1-1/8 | 1-1/4 | 1-3/8 | 1-1/2 | |
| ds | Max. | 0.26 | 0.324 | 0.388 | 0.452 | 0.515 | 0.642 | 0.768 | 0.895 | 1.022 | 1.149 | 1.277 | 1.404 | 1.531 |
| Min. | 0.237 | 0.298 | 0.36 | 0.421 | 0.483 | 0.605 | 0.729 | 0.852 | 0.976 | 1.098 | 1.223 | 1.345 | 1.47 | |
| dk | Max. | 0.493 | 0.618 | 0.74 | 0.803 | 0.935 | 1.169 | 1.402 | 1.637 | 1.869 | 2.104 | 2.337 | 2.571 | 2.804 |
| Min. | 0.477 | 0.598 | 0.715 | 0.778 | 0.905 | 1.132 | 1.357 | 1.584 | 1.81 | 2.037 | 2.262 | 2.489 | 2.715 | |
| k | Max. | 0.15 | 0.189 | 0.225 | 0.226 | 0.269 | 0.336 | 0.403 | 0.47 | 0.537 | 0.604 | 0.671 | 0.738 | 0.805 |
| Min. | 0.131 | 0.164 | 0.196 | 0.196 | 0.233 | 0.292 | 0.349 | 0.408 | 0.466 | 0.525 | 0.582 | 0.641 | 0.698 | |
| n | Max. | 0.075 | 0.084 | 0.094 | 0.094 | 0.106 | 0.133 | 0.149 | 0.167 | 0.188 | 0.196 | 0.211 | 0.226 | 0.258 |
| Min. | 0.064 | 0.072 | 0.081 | 0.081 | 0.091 | 0.116 | 0.131 | 0.147 | 0.166 | 0.178 | 0.193 | 0.208 | 0.24 | |
| t | Max. | 0.068 | 0.086 | 0.103 | 0.103 | 0.103 | 0.137 | 0.171 | 0.206 | 0.24 | 0.257 | 0.291 | 0.326 | 0.36 |
| Min. | 0.045 | 0.057 | 0.068 | 0.068 | 0.068 | 0.091 | 0.115 | 0.138 | 0.162 | 0.173 | 0.197 | 0.22 | 0.244 | |
①,Minimum thread length:
The minimum length of the threads shall be equal to twice the basic bolt diameter plus 0.25 inch for nominal bolt lengths of 6 inches or less, and twice the basic bolt diameter plus 0.50 inch for longer nominal lengths.
Bolts whose nominal length is too short to accommodate the minimum thread length shall be fully threaded. The length from the head or neck to the first full (full) thread shall not exceed 2-1/2 threads (sizes 1 inch or less) and 3-1/2 threads (sizes greater than 1 inch).
FAQ
A: We take every inquiry seriously. On working days, we will respond within 12 hours after receiving your inquiry.
A: We focus on the production of fasteners made of carbon steel, stainless steel, and low-alloy steel. We are a direct manufacturer with independent production capacity. ASME/ANSI B18.5 (T7):2012 Inch Series Countersunk Head Slotted Bolt Factory. We own several fastener manufacturing facilities and have an international sales department, providing full-process services from production to export.
A: Customized production is our core business. We can develop and manufacture products based on the drawings or samples you provide.
A: Yes. In addition to custom products, we also produce general construction machinery parts (GET parts) for equipment such as excavators, including bucket teeth, tooth holders, corner blades, pins, clips, bolts and nuts. ASME/ANSI B18.5 (T7):2012 Inch Series Countersunk Head Slotted Bolt Wholesale.
A: We have 12 energy-efficient and environmentally friendly modern production lines (including one fully automatic shell molding line and four heat treatment lines), with an annual production capacity exceeding 20,000 tons, enabling us to steadily meet various order requirements.
A: Trade terms (such as FOB, CIF, etc.) are confirmed when quoting. For batch production, we typically require a 30% deposit, with the balance paid against the copy of the bill of lading. T/T is the main payment method accepted, and L/C can also be negotiated.
A: We are only 35 km away from Shanghai Port and Ningbo Port, so sea freight is the main mode of transportation, which is convenient and efficient. For urgent deliveries, we can also arrange air freight via Ningbo or Shanghai airports.
About Us
Better Fastener is a professional fastener enterprise specializing in the manufacturing of steel washers, stainless steel washers, spring washers and sealingwashers. Founded in 2001 as a washer factory, the company expanded into a comprehensive enterprise integrating washers, nuts, bolts, spring nuts and other fastener products in 2010. ASME/ANSI B18.5 (T7):2012 Inch Series Countersunk Head Slotted Bolt Suppliers in China.
The company positions itself as a provider of comprehensive one-stop services for customers, relying on technological R&D, industrial investment and trade distribution.
With an experienced professional team and a sound sales network, Better Fastener has achieved excellent sales performance in both domestic and foreign markets,and has grown into one of the competitive manufacturers and suppliers in China's industrial fastener industry.
Better Fastener is committed to becoming a trusted fastener supplier for customers with reliable product quality, reasonable prices and on-time deliveryNEWS