DIN 1587 Titanium Acorn Nuts — High-Strength Dome Cap Fasteners for Industrial Applications

DIN 1587 titanium acorn nuts are high-precision hexagon domed cap nuts manufactured to German DIN standards, available in Grade 2 and Grade 5 titanium alloys. The closed dome design fully covers exposed bolt threads, eliminating sharp-end hazards and sealing connections from corrosion. Compared to standard steel counterparts, these titanium cap nuts deliver approximately 45% weight reduction and outstanding resistance to saltwater and chemical attack. At Baoji Huacan, we produce them using 40+ CNC machines with full OEM/ODM customization capability.

Technical Specifications

Parameter	Details
Product Standard	DIN 1587 Acorn Nut Standard
Material Grades	Grade 2 (TA2), Grade 5 (Ti-6Al-4V), Grade 7, Grade 9, Grade 23 (Custom grades available)
Material Standards	ASTM B348, AMS 4928, DIN, ISO standards
Thread Type	Internal metric thread
Thread Size	Customized according to customer requirements
Thread Tolerance	6H class
Dome Height	High dome type, approximately equal to thread diameter
Dimensional Range	Fully customized based on customer drawings or specifications
Surface Finish	Natural titanium finish, polished, anodized, or PVD coating
Tensile Strength	Up to approx. 895 MPa (Grade 5 Titanium)
Density	Approx. 4.51 g/cm³
Maximum Service Temperature	Up to 400°C (Grade 5) / 300°C (Grade 2)
Manufacturing Process	CNC machining, precision turning, prototype to mass production
Custom Options	OEM / ODM services available

Thread Size			M4	M5	M6	M8	M10	M12	(M14)	M16	(M18)	M20	(M22)	M24
D
P	Coarse thread		0.7	0.8	1	1.25	1.5	1.75	2	2	2.5	2.5	2.5	3
	Fine thread -1		/	/	/	1	1.25	1.5	1.5	1.5	2	2	2	2
	Fine thread -2		/	/	/	/	1	1.25	/	/	1.5	1.5	1.5	/
da	max		4.6	5.75	6.75	8.75	10.8	13	15.1	17.3	19.5	21.6	23.7	25.9
da	min		4	5	6	8	10	12	14	16	18	20	22	24
dk	min=nominal size		6.5	7.5	9.5	12.5	15	17	20	23	26	28	33	34
dw	min		5.9	6.9	8.9	11.6	14.6	16.6	19.6	22.5	24.9	27.7	31.4	33.3
e	Grade A	min	7.66	8.79	11.05	14.38	17.77	20.03	23.35	26.75	30.14	33.53	37.72	39.98
e	Grade B	min	7.5	8.63	10.89	14.2	17.59	19.85	22.78	26.17	29.56	32.95	37.29	39.55
x	Coarse thread	max	1.4	1.6	2	2.5	3	3.5	4	4	5	5	5	6
x	Fine thread	max	/	/	/	2	2.5	3	3	3	4	4	4	4
G	Coarse thread	max	2.75	3	3.7	4.9	5.6	6.4	7.3	7.3	9.3	9.3	9.3	10.7
G	Fine thread	max	/	/	/	3.7	4.9	5.6	5.6	5.6	7.3	7.3	7.3	7.3
h	max=nominal size		8	10	12	15	18	22	25	28	32	34	39	42
	Grade A	min	7.64	9.64	11.57	14.57	17.57	21.48	24.48	27.48	31.38	33.38	38.38	41.38
	Grade B	min	7.42	9.42	11.3	14.3	17.3	21.16	24.16	27.16	31	33	38	41
m	max		3.2	4	5	6.5	8	10	11	13	15	16	18	19
m	min		2.9	3.7	4.7	6.14	7.64	9.64	10.3	12.3	14.3	14.9	16.9	17.7
mw	min		2.32	2.96	3.76	4.91	6.11	7.71	8.24	9.84	11.44	11.92	13.52	14.16
SR	≈		3.25	3.75	4.75	6.25	7.5	8.5	10	11.5	13	14	16.5	17
s	max=nominal size		7	8	10	13	16	18	21	24	27	30	34	36
	Grade A	min（Grade A）	6.78	7.78	9.78	12.73	15.73	17.73	20.67	23.67	26.67	29.67	33.38	35.38
	Grade B	min（Grade B）	6.64	7.64	9.64	12.57	15.57	17.57	20.16	23.16	26.16	29.16	33	35
t	max		5.74	7.79	8.29	11.35	13.35	16.35	18.35	21.42	25.42	26.42	29.42	31.5
t	min		5.26	7.21	7.71	10.65	12.65	15.65	17.65	20.58	24.58	25.58	28.58	30.5
w	min		2	2	2	2	2	3	4	4	5	5	5	6
per 1000 units≈kg	Coarse thread		1.5	2.2	4.6	8.9	20.1	28.3	39.7	54.3	79.1	104	/	216
per 1000 units≈kg	Fine thread		/	/	/	11	20.1	28.3	39.7	54.3	95	104	/	216

Application Field	Description
Bicycle & Cycling Components	Ideal for premium road bikes, MTB, BMX, and custom builds requiring lightweight, corrosion-resistant, and visually appealing fasteners.
Automotive & Motorsport	Suitable for racing vehicles, performance cars, and custom modifications where weight reduction, strength, and aesthetics are critical.
Motorcycle Components	Used for fairings, body panels, engine covers, and exposed fastening locations requiring durable and high-quality titanium hardware.
Marine & Yacht Equipment	Designed for boats, yachts, and coastal applications where excellent saltwater corrosion resistance is essential.
Outdoor & Sporting Equipment	Applied in lightweight gear, climbing equipment, and custom assemblies exposed to harsh outdoor environments.
Industrial & Precision Machinery	Used in specialized equipment and precision assemblies requiring reliable fastening, low weight, and long-term durability.

Bicycle & Cycling

Motorcycle Modification

Automotive Performance & Racing

· Dome closure: Fully encases the bolt end, blocking moisture, salt, and chemicals from reaching the thread

· Non-magnetic: Permeability < 1.001 — no interference with electronics or medical devices

· Lightweight: ~45% lighter than equivalent steel fasteners

· High strength-to-weight ratio: Grade 5 reaches ~895 MPa tensile strength

· Corrosion resistant: Excellent performance in chloride, acid, and alkaline environments

· Aesthetic finish: Polished or anodized surface available for visible applications

· High melting point: ~1,668°C — stable at elevated operating temperatures

Material Features

Our acorn nuts are made from certified Grade 2 and Grade 5 (Ti-6Al-4V) titanium alloys and fulfil ASTM, AMS and DIN material requirements.

Grade 5 titanium has a tensile strength of up to ~895 MPa which is similar to that of alloy steel but with a density of only 4.51 g/cm3. This combination is hard to beat with any other fastening material.

The nuts are 100% non-magnetic (permeability < 1.001) and safe for MRI and sensitive electrical devices. They also retain structural integrity up to 400°C (Grade 5) or 300°C (Grade 2).

We have over 10 years expertise in titanium machining with an annual capacity of over 1,000 tonnes. We cater for both small batch prototype orders to big volume industrial supply.

Each titanium acorn nut starts with certified raw titanium bar stock, verified by chemical composition analysis before entering production.

CNC precision turning and thread machining are performed on our 40+ advanced machining centers, including gantry systems. This ensures tight dimensional tolerances and consistent thread engagement depth across every batch.

The blind dome cavity requires exact thread depth calculation to prevent bolt bottoming inside the nut. Our machining team controls this critical dimension according to your drawings or DIN 1587 specifications.

Post-machining, each nut goes through deburring, surface finishing, and cleaning before dimensional inspection and packaging.


Material Preparation	Heading / Forging	Heat Treatment	Precision Machining

Thread Manufacturing	Cleaning	Inspection	Surface Treatment

Our multi-stage QC process is designed specifically for precision fasteners like titanium acorn nuts.

Material verification: Incoming titanium bar is checked by XRF (X-Ray Fluorescence) to confirm grade composition — Al/V content for Grade 5, purity level for Grade 2.

Dimensional inspection: Calibrated thread plug gauges (Go/No-Go) verify 6H tolerance class. CMMs and optical tools confirm dome geometry, hex "across flats" measurements, and critical depth dimensions.

Surface examination: Visual inspection at 10× magnification finds forging bursts, laps or surface imperfections on the dome.

Mechanical testing: Proof load testing verifies that the thread stripping strength fulfils modified ISO 898-2 criteria for titanium and that the nut does not fail before the mating bolt.

Final check: Inspection reports, material traceability records, MTC/COC certifications are all produced before shipping.

Certifications

Baoji Huacan New Metal Materials Co., Ltd. has passed ISO 9001 quality management system certification, encompassing all manufacturing processes from selection of raw materials to final inspection and shipping.

Our methods are built on ASTM, AMS and DIN international standards. Material certifications (MTC, EN10204 3.1, COC) may be supplied on request.

We support full OEM/ODM customization for industrial and specialty buyers.

· Thread size, pitch, and type: customized per drawing

· Dimensional size: diameter, dome height, and hex width adjusted per requirements

· Material grade: Grade 2, Grade 5, Grade 7, Grade 9, Grade 23 available

· Surface finish: natural titanium, polished, anodized, PVD coating, or custom color

· Laser marking or CNC engraving for part numbers or logos

· Prototype orders and mass production both supported

Send your drawing or specification to Joy@hc-titanium.com for a tailored quote.

Each batch of titanium acorn nuts is packaged to prevent surface damage and contamination during transit.

· Custom foam inserts for delicate components

· Vacuum-sealed bags with desiccants for moisture protection

· Sturdy wooden crates for bulk shipments

· Detailed labeling and documentation for easy tracking

We offer air freight for urgent orders and sea freight for cost-effective bulk shipments worldwide. Flexible logistics options are available based on your delivery requirements.

Q: Can the product replace stainless steel directly?

A: Yes, they are dimensionally identical to DIN 1587 steel versions. Just ensure your bolt length is precise to avoid the end bottoming out inside the dome.

Q: How do I prevent galling during installation?

A: Titanium threads may be cold-welded under pressure. Before assembly, use a molybdenum disulphide lubricant or an anti-seize paste to avoid thread seizing.

Q: Grade 2 or Grade 5, what should I choose?

A: For non-structural applications choose Grade 2 for best corrosion protection and cost saving. Choose Grade 5 when the junction has heavy structural loads.

Q: Are these nuts magnetic?

A: No. Titanium acorn nuts are 100% non-magnetic (permeability < 1.001), safe for MRI machines and electronic assemblies.

Q: Do you support small orders or samples?

A: Yes. We support prototype quantities, small batches, and full production runs. Contact us with your drawing or specification to get started.