Inconsistent Thread Quality

A major automotive Tier-2 supplier reported 18% scrap rate on a 50,000-unit order due to cross-threading. Cost: $23,000 in rework + line downtime.

Hidden Shipping & Tariff Costs

A US machinery startup paid 42% more than quoted after surprise freight surcharges. With our factory-direct DDP pricing, you pay what you see — no surprises.

Brittle Material, Field Failures

A European construction firm had 12% of 4 40 socket cap screws snap during installation. Their supplier used 303 stainless instead of 304/316. We test every batch.

Minimum Order Quantity (MOQ) Lock-In

Why buy 100,000 pieces when you need 12,000? Big distributors force MOQ. We offer no MOQ on standard sizes and flexible kitting for prototypes.

Long Lead Times (8–12 weeks)

A German automation company waited 67 days for a simple 4-40 hex socket order. We ship standard items in 10–15 working days, air express in 5–7 days.

Certification Gaps (RoHS, REACH, CE)

A UK medical device startup was rejected by their auditor because their fastener supplier couldn't provide full material traceability. We provide mill test reports with every shipment.

Powerful Factory

12,000 sqm facility, 50+ CNC cold-forming lines, and 8 million pieces/month capacity. Your order never waits.

Quality Assurance

ISO 9001:2015 certified. Every batch tested for hardness, tensile strength, and thread gauge. 99.7% pass rate on first inspection.

High-Speed Delivery

Standard: 10–15 days (FOB Tianjin/Shanghai). Express: 5–7 days via DHL/FedEx. DDP options for USA & EU buyers.

OEM/ODM Design

Custom head markings, special coatings (Zn/Ni, Dacromet, PTFE), non-standard lengths, and drive types. Engineering support included.

Unbeatable Value

Factory-direct pricing eliminates 3–4 layers of markup. Buyers save 30–50% vs. local distributors on equivalent quality.

Automotive & EV

Used in ECU housings, battery pack connectors, brake systems, and interior trim. Case study: A US EV startup switched to our 4 40 socket cap screws (Grade 12.9, Zn/Ni coated) and reduced fastener failures by 72% over 6 months.

Industrial Machinery

CNC machine guards, conveyor systems, robotic arms, and hydraulic pump assemblies. A German machine builder reported 27% faster assembly after switching to our consistent-thread 4 40 allen head screws.

Construction & Structural

Steel framing brackets, handrail systems, electrical enclosure mounts. Our 316 SS 4 40 socket cap screws pass 1,000-hour salt spray testing — ideal for coastal and offshore environments.

Agricultural Machinery

Tractor panels, irrigation controllers, seed drill components. A French farm equipment OEM saved €0.08 per unit by switching to our factory-direct pricing — that's €24,000/year on their annual volume.

David Chen Purchasing Manager, US Automotive Tier-1

"We switched from a US distributor to Boen for our 4 40 socket cap screws. 37% cost reduction and zero quality issues in 6 months. Their Zn/Ni coating held up perfectly in our salt spray test."

Anna Schmidt Technical Director, German Machinery GmbH

"The thread consistency of their 4 40 allen head screws is remarkable. We cut our assembly rework by 63%. The mill test reports give us full traceability for our ISO audits."

Q1: What is the difference between a 4 40 allen head screw and a 4 40 socket cap screw?

Answer: In common usage, the terms are often interchangeable. However, technically, a 4 40 allen head screw refers to any screw with a hex socket drive, while 4 40 socket cap screw specifically describes a low-profile cylindrical head (per ASME B18.3). We supply both styles — plus button, flat, and low-head variants — all from stock.

Q2: What materials do you offer for 4-40 fasteners?

Answer: We stock Alloy Steel (Grade 8.8, 10.9, 12.9), Stainless Steel (304, 316, 410), Brass, and 7075 Aluminum. For specialized applications, we also offer Inconel, Hastelloy, and Titanium on a made-to-order basis. All materials are fully traceable with mill certificates.

Q3: Do you offer custom lengths or head markings for 4 40 socket cap screws?

Answer: Absolutely. We provide OEM/ODM services including custom lengths (down to 0.1mm precision), special drive sizes, head markings (logos, grades, torque indicators), and unique coatings. Minimum order for custom: 5,000 pieces per size. Engineering support is included at no extra cost.

Q4: What are your typical lead times and shipping options?

Answer: Standard items ship in 10–15 working days (FOB Tianjin/Shanghai). Express air freight (DHL/FedEx) takes 5–7 working days. For large orders, we offer DDP (Delivered Duty Paid) to USA and EU addresses — you pay one price, no surprises. We also offer consolidated shipping for mixed orders.

Q5: How do you ensure quality control for 4 40 allen head screws?

Answer: Every batch is tested in our in-house QC lab for: hardness (Rockwell), tensile strength, thread gauge (GO/NO-GO), and salt spray resistance. We also provide full material traceability from mill to finished product. Our ISO 9001:2015 certification is backed by annual audits. 99.7% first-pass yield — we reject before you receive.

Q6: What is the minimum order quantity (MOQ)?

Answer: For standard 4 40 socket cap screws (alloy steel, 304 SS), MOQ is 1,000 pieces per size. For stainless steel, brass, and aluminum, MOQ is 500 pieces. For custom items, MOQ is 5,000 pieces. We understand small-batch needs — contact us for prototype and sample orders (no minimum).

Q7: Do you have distributors in the USA or Europe?

Answer: We sell direct from our factory in Handan, China to global buyers. This is how we keep prices 30–50% lower than local distributors. We ship DDP to USA and EU, so you get door-to-door delivery with all duties and taxes included. No middleman, no markup.

Q8: Can I get free samples before placing a bulk order?

Answer: Yes! We offer free samples (up to 10 pieces per size) for standard 4 40 allen head screws and socket cap screws. You pay only shipping. Sample orders ship within 3 working days. This is our way of proving quality before you commit.

Marcus J. — Supply Chain Manager, UK Construction

"We ordered 50,000 4 40 socket cap screws in 316 SS. The quality is superb — consistent thread, no burrs. Saved 44% vs our previous supplier. Delivery was 11 days. We've switched all our fastener sourcing to Boen."

Elena V. — Technical Buyer, Italian Automation

"The 4 40 allen head screws from Boen are the best we've tested. The hex socket drive is clean and deep — no stripping. Our assembly line rejection rate dropped from 4% to 0.2%. Highly recommended."

James T. — CEO, US Agricultural Equipment

"We were skeptical about importing fasteners, but Boen made it easy. DDP pricing meant no hidden fees. The cost savings of 37% directly improved our margin. The 4 40 socket cap screws are holding up perfectly in our field equipment."