Slotted Countersunk Head Bolt & 8 Galvanized Carriage Bolts | Maker
Slotted Countersunk Head Bolt & 8 Galvanized Carriage Bolts | Maker
Slotted Countersunk Head Bolt & 8 Galvanized Carriage Bolts with Nuts and Washers โ Factory-Direct Maker
โ๏ธ Engineered for flush-mount precision and corrosion-resistant structural joining โ ISO 9001 quality, 30+ country exports, and 30% lower TCO vs. Western distributors.
Trusted by procurement teams in automotive, construction, and agricultural machinery across Europe & North America.
โ ๏ธ The Hidden Cost of Sourcing slotted countersunk head bolt & carriage bolts from the wrong supplier
Price volatility & hidden fees
Spot-market pricing for 8 galvanized carriage bolts with nuts and washers can swing 15-25% quarterly. Add freight surcharges, and your landed cost becomes unpredictable.
Inconsistent quality & reject rates
A major agricultural OEM reported 12% rejection on imported carriage bolts due to off-spec square neck dimensions. Downtime cost: โฌ4,200 per hour.
Ocean freight & lead time risk
Container shipping from Asia to Rotterdam or Los Angeles still averages 35-45 days. One delay can stall your entire production line.
Compliance & documentation gaps
Missing CE marking or incorrect material certs can block customs. 37% of importers faced delayed clearance in 2025 due to non-compliant fasteners (source: EC import audit).
Limited customization & technical support
Most traders can't modify head height, thread length, or plating thickness. You need a maker who understands your engineering drawings.
Total cost of ownership (TCO) blind spot
Low unit price + high reject rate + expedited freight + admin overhead = up to 40% higher TCO than a stable, certified factory partner.
๐ You're not alone. 73% of procurement managers say fastener quality and supply stability are their top two concerns for 2026. See how Boen solves this โ
โ Boen Precision Fastener Solution โ slotted countersunk head bolt & carriage bolts engineered for industrial performance
Factory-Direct slotted countersunk head bolt
Produced on CNC cold-forging lines with in-house heat treatment. DIN 963 / ISO 2009 compliant. Flush-fit countersink angle: 90ยฐ ยฑ1ยฐ for clean, snag-free assemblies.
- M3 โ M20 diameter range
- Grades 4.8, 8.8, 10.9, A2-70, A4-80
- Zinc plated, HDG, or black oxide
- 0.8 ฮผm Ra surface finish option
8 Galvanized Carriage Bolts with Nuts and Washers
Complete ready-to-install kit. Hot-dip galvanized (HDG) per ASTM A153. Square neck fully formed to prevent spin-out during tightening. Salt spray resistance: 500+ hours.
- 1/4โณ โ 3/4โณ diameter (or metric M6โM16)
- Lengths: 1โณ โ 8โณ (custom up to 12โณ)
- Includes class 8.8 hex nut & flat washer
- Tested to ASTM F568M standard
High-Speed Delivery & Supply Stability
Our 3-week lead time for standard sizes beats the industry average by 40%. Dedicated buffer stock for high-volume SKUs ensures 98% on-time dispatch.
- 20-ft container: 15โ18 working days
- Express LCL: 10โ12 working days
- ERP integration: EDI, CSV, or API
- Free sample for pre-production approval
๐ Technical Specifications โ slotted countersunk head bolt & 8 galvanized carriage bolts
| Parameter | Slotted Countersunk Head Bolt | 8 Galvanized Carriage Bolts (Kit) |
|---|---|---|
| Standard | DIN 963 / ISO 2009 | DIN 603 / ASTM A307 Grade A |
| Material | Carbon steel, stainless steel 304/316, brass | Carbon steel, hot-dip galvanized (HDG) |
| Grade | 4.8 / 8.8 / 10.9 / A2-70 / A4-80 | 4.6 / 8.8 (nut: class 8) |
| Diameter range | M3 โ M20 (inch: #6 โ 3/4โณ) | M6 โ M16 (1/4โณ โ 5/8โณ) |
| Length range | 8 mm โ 200 mm (custom up to 300 mm) | 25 mm โ 200 mm (1โณ โ 8โณ) |
| Head angle | 90ยฐ ยฑ1ยฐ (countersink) | Domed head, square neck (10 mm ร 10 mm) |
| Plating / coating | Zinc, HDG, black oxide, Dacromet, passivated | Hot-dip galvanized (โฅ 50 ฮผm) |
| Corrosion resistance | Salt spray 72โ500 h (depending on coating) | Salt spray โฅ 500 h |
| Tensile strength | 400 โ 1200 MPa (grade dependent) | 400 โ 800 MPa |
| Packaging | Bulk 25 kg cartons, small boxes, or poly bags | Kit: 8 bolts + 8 nuts + 8 washers per poly bag |
*Custom sizes, materials, and packaging available upon request. Contact our engineering team for OEM/ODM projects.
Agricultural machinery
Carriage bolts for harvester tines, slotted countersunk bolts for panel mounting. Used by 3 major European OEMs.
Construction & structural steel
Flush-fit bolts for handrails, scaffolding, and steel frame connections. CE marked for construction.
Automotive & trailer manufacturing
Countersunk bolts for floor panels, carriage bolts for chassis assemblies. IATF 16949 aligned process.
Renewable energy (solar/wind)
Corrosion-resistant fasteners for solar tracker structures and wind turbine towers. 25-year durability target.
โ Frequently Asked Questions โ slotted countersunk head bolt & carriage bolts
A: Standard sizes (M6โM16, 1โณโ6โณ) ship in 15โ18 working days for a full 20-ft container. Express LCL orders available in 10โ12 days. We also keep buffer stock for repeat orders.
A: Yes. Our toolroom can modify head angle (60ยฐโ120ยฐ), slot width/depth, and underhead radius. Send your drawing or sample for a free engineering review.
A: All fasteners are manufactured under ISO 9001:2015. We provide CE, RoHS, FCC, and UL certifications where applicable. Material test reports (MTR) and batch traceability included.
A: Absolutely. We provide free samples (you pay shipping). Sample lead time: 3โ5 working days. Pre-production samples (PPAP) available for approval before mass production.
A: MOQ for standard sizes: 5,000 pcs per size. For custom dimensions or special materials, MOQ starts at 2,000 pcs. We can also accommodate trial orders of 1,000 pcs for new customers.
A: We follow ASTM A153 / ISO 1461 for hot-dip galvanizing. In-house testing includes coating thickness gauge, salt spray chamber, and adhesion bend test. Certificates issued batch-wise.
A: We accept T/T (30% deposit, 70% before shipment), L/C at sight, and for established customers โ net 30 days (subject to credit approval). We also support Alibaba Trade Assurance.
A: Yes. Our engineering team offers free technical consultation on fastener selection, torque values, and installation. We also provide installation guides and video support for large projects.
โญ Real Reviews from Buyers Across the Globe
โWe use Boen's slotted countersunk head bolts for our bridge railing systems. The consistency of the 90ยฐ countersink is remarkable โ no more sanding down proud heads. Installation time reduced by 18%.โ
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โOrdered 8 galvanized carriage bolts with nuts and washers for our turbine tower assembly. The HDG coating passed our 600-hour salt spray test. Delivery was 3 days ahead of schedule.โ
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โBoen helped us consolidate 4 fastener suppliers into 1. Their OEM design support for a custom carriage bolt saved us โฌ0.12 per unit โ โฌ18,000 annual savings. Excellent communication throughout.โ
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Ready to Secure Factory-Direct Pricing on Your Next Fastener Order?
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Free samples for pre-production approval
โ
15โ18 day lead time for standard slotted countersunk head bolt & 8 galvanized carriage bolts with nuts and washers
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ISO 9001 ยท CE ยท RoHS โ full documentation included
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30-day money-back guarantee on first order if not satisfied
Or email us directly: shuan@fastenboen.com ยท mary@fastenboen.com ยท grace@fastenboen.com ยท stella@fastenboen.com
๐ Hanguang Industrial Park, Yongnian District, Handan City, Hebei Province, China ยท MonโFri 09:00โ17:00
๐ญ Factory Strength & Global Trust โ Boen Fasteners
Trusted by procurement teams at:
We switched to Boen for our 8 galvanized carriage bolts with nuts and washers. Reject rate dropped from 9% to 0.3%. Saved us โฌ28,000 in the first year.
The slotted countersunk head bolt quality from Boen is outstanding. Consistent 90ยฐ head angle, clean slots, and the zinc plating is flawless. We now use them for all our control panels.
Boen's factory-direct pricing and fast delivery transformed our supply chain. We reduced inventory by 30% while improving line fill rate to 99%.