What is the difference between DIN6912 and DIN912?

DIN6912 has a lower head height and includes a pilot recess for the DIN6911 key. Use DIN6912 for flush-mount or confined spaces; DIN912 for maximum torque applications.

What hex key does DIN6912 use?

DIN6912 requires a DIN6911 hex key with pilot tip, not a standard DIN911 key. The center pilot engages the socket recess for better alignment during installation.

What is the DIN6912 pilot recess for?

The pilot recess allows the DIN6911 key to self-center, preventing cam-out during automated assembly. Critical for precision and high-speed production applications.

What grade is DIN6912 available in?

DIN6912 is available in Grade 08.8 carbon steel (zinc-plated) and A2-070 stainless steel. Grade 08.8 for high strength; A2-070 for corrosion resistance in food-grade or marine environments.

Can I order custom DIN6912 specifications?

Yes, DingLong Hardware offers custom lengths, coatings (black oxide, Dacromet), and material certifications. Contact via the quote form for bulk order specifications.

DIN938 Double End Stud Bolt Manufacturer

Metric double-end stud bolts with 1d screwing-in length — M3 to M52, carbon steel, stainless steel, and alloy steel. ISO 9001:2015 certified production, EN 10204 3.1 certificates supplied.

M3–M52 Thread Sizes · Custom Lengths Available
Grades: 8.8 / 10.9 / 12.9 / A2-70 / A4-70 / A4-80
Lead Time: 3–5 Days (Stock) / 7–15 Days (Custom)
EN 10204 3.1 Material Certificates on Request

500+

B2B Clients Worldwide

15+ Years

Fastener Manufacturing

ISO 9001:2015

Quality Management

24 Hours

Quotation Response

DIN938 Stud Bolt Quick Specifications

Standard

DIN 938

Thread Size

M3 – M52

Engagement

bm = 1 × d

Materials

8.8 / 10.9 / A2-70 / A4-70

What Is a DIN938 Double End Stud Bolt?

DIN938 is a metric double-end stud bolt standard where the screwing-in end length equals exactly one times the nominal thread diameter (bm = 1d). This short engagement length is engineered for high-strength base materials — steel, cast steel, and bronze — where the thread can develop full load-bearing capacity in a compact depth.

Unlike hex bolts, DIN938 studs do not rotate during tightening, eliminating galling in precision tapped bores. The fixed screwing-in end stays in the housing; only the nut end accepts the nut.

Three structural zones define every DIN938 stud:

Screwing-in End (b1)

Thread equal to 1×d; engages the base material permanently.

Shank (L − b1 − b2)

Plain or threaded body spanning the joint gap.

Nut End (b2)

Longer thread (≈2×d) that accepts washer and nut.

DIN938 Dimension & Property Class Tables

Complete M3–M52 dimensions per DIN 938, plus mechanical property benchmarks for every standard grade. All dimensional values in millimetres.

Use this table to confirm thread size, pitch, screwing-in length (b1), nut-end length (b2), and minimum available length before ordering. All dimensions in mm per DIN 938.

Thread d	Pitch (mm)	b1 (mm)	b2 (mm)	x max	Min Length (mm)
M3	0.50	3	6	1.25	10
M4	0.70	4	8	1.50	12
M5	0.80	5	10	1.75	16
M6	1.00	6	12	2.00	20
M8	1.25	8	16	2.50	25
M10	1.50	10	20	3.00	30
M12	1.75	12	24	3.50	40
M16	2.00	16	32	4.00	55
M20	2.50	20	40	5.00	70
M24	3.00	24	48	6.00	90
M30	3.50	30	60	7.50	110
M36	4.00	36	72	9.00	130
M42	4.50	42	84	10.50	150
M48	5.00	48	96	12.00	170
M52	5.00	52	104	13.00	190

Property Class Mechanical Properties (per ISO 898-1 / ISO 3506)

Grade	Material	Min Tensile	Min Yield (0.2%)	Hardness	Best For
8.8	Carbon Steel	800 N/mm²	640 N/mm²	22–32 HRC	General structural, indoor
10.9	Carbon Steel	1040 N/mm²	940 N/mm²	33–39 HRC	High-strength structural
12.9	Alloy Steel	1220 N/mm²	1100 N/mm²	39–44 HRC	Precision/critical joints
A2-70	Stainless 304	700 N/mm²	450 N/mm²	≤ 250 HV	Food, chemical, indoor corrosion
A4-70	Stainless 316	700 N/mm²	450 N/mm²	≤ 250 HV	Marine, chloride environments
A4-80	Stainless 316	800 N/mm²	600 N/mm²	≤ 250 HV	High-load + corrosive environments

DIN938 Material Grades

Select the correct grade for your operating environment and load requirements.

Carbon Steel

Grades: 8.8 / 10.9 / 12.9

Standard structural grade. 8.8 for general use, 10.9 for high-strength structural joints, 12.9 for precision mechanical assemblies. Zinc plating or Dacromet recommended.

Stainless Steel

Grades: A2-70 / A4-70 / A4-80

Corrosion-resistant for chemical, food-grade, and marine environments. A4-70/80 (316 SS) preferred for chloride exposure. Non-magnetic options available.

Alloy Steel

Grades: 42CrMo4 / 25CrMo4 / 35CrMo

High-strength, high-temperature alloy grades for petrochemical flanges, pressure vessels, and engineering equipment. Proof load values per ISO 898-1.

Surface Treatment Options

For high-strength grades 10.9 and 12.9, Dacromet or mechanical zinc is recommended to eliminate hydrogen embrittlement risk from electroplating.

Plain / Black

Standard mill finish. Suitable for indoor, oiled, or coated assemblies.

Zinc Plated

Electroplated zinc, 5–8 µm. General-purpose corrosion protection, RoHS compliant.

Hot-Dip Galvanized

40–80 µm zinc coating. Outdoor, structural, and heavy-duty applications.

Dacromet / Geomet

Chrome-free inorganic zinc flake. 8–12 µm, 720 h salt-spray. Recommended for grade 10.9/12.9 to avoid hydrogen embrittlement.

PTFE / Fluoropolymer

Low-friction, chemical-resistant coating. Food-grade and clean-room environments.

DIN938 vs DIN939 vs DIN940

The three DIN stud standards share identical thread forms and property classes but differ in screwing-in length (bm). The correct choice depends on the tapped hole material — selecting too short a bm risks thread strip-out under load.

Standard	Screwing-in Length (bm)	Best For	Typical Tensile Strength
DIN 938	1 × d	Steel, cast steel, bronze (hardness ≥ 200 HB)	800–1220 N/mm²
DIN 939	1.25 × d	Cast iron, aluminum alloy (medium hardness)	800–1220 N/mm²
DIN 940	1.5 × d	Light alloys, soft metals (low hardness)	800–1220 N/mm²

Rule of thumb: use DIN 938 when the tapped hole is in steel or harder materials. Step up to DIN 939 for aluminium or cast iron, DIN 940 for magnesium or plastics.

Need deeper thread engagement? DIN939 Double End Stud Bolt (1.25d) — Full Specifications & Dimensions

DIN938 Stud Bolt Applications

Mechanical Equipment Assembly

Connecting pump housings, gearbox covers, and precision machine frames where bolt rotation would damage tapped bores.

Petrochemical & Pipeline Flanges

High-temperature, high-pressure flange joints in refineries, pressure vessels, and heat exchangers. Alloy steel grade recommended.

Structural Steel Connections

Moment-resistant connections in steel construction where pre-tensioned studs replace through-bolts.

Automotive & Precision Engineering

Engine block head studs, brake caliper mounts, and suspension systems requiring consistent clamp force.

Quality Certifications & Documentation

Every DIN938 stud bolt order ships with traceable quality documentation. Our ISO 9001:2015 certified process ensures consistent dimensional accuracy and material compliance.

ISO 9001:2015

Certified quality management system covering design, production, testing, and delivery of DIN-standard fasteners.

EN 10204 3.1 Certificates

Full material test certificates with chemical composition and mechanical test data available for every batch.

SGS Third-Party Testing

Independent SGS lab verification of tensile strength, hardness, and thread gauge available on request.

RoHS Compliant Coatings

All zinc-plated and Dacromet surface treatments comply with EU RoHS Directive 2011/65/EU.

Why Source DIN938 Stud Bolts From Us?

We manufacture DIN938 double end stud bolts from cold-forged blanks using precision CNC thread rolling, ensuring dimensional accuracy within ISO 4759 tolerances. Every batch undergoes hardness, tensile strength, and thread gauge inspection before shipment. No middlemen — direct factory pricing with full documentation.

Stock: M6–M36 in grades 8.8, A2-70, A4-70 — ready in 3–5 business days
Custom production: M3–M52, any length, any grade, MOQ 500 pcs
Thread rolling precision: ISO 4759 tolerances, pitch gauge 100% checked
EN 10204 3.1 material certificates included with every batch
Surface options: zinc plated, HDG, Dacromet, Geomet, Black oxide, PTFE
OEM packaging: custom labelling, box/bag/pallet, export-ready
Quote turnaround: 24 hours for standard items, 48 hours for specials
Save at least 30% vs European distributor pricing on equivalent DIN grades

Related Fastener Products

DIN 939 Stud Bolts

Engagement length 1.25×d — for cast iron and aluminium alloys.

DIN 940 Stud Bolts

Engagement length 1.5×d — for light alloys and soft metals.

DIN 976 Threaded Rods

Full-length metric threaded rod, cut to custom lengths.

DIN 934 Hex Nuts

Standard metric hex nuts, all property classes.

Need Custom DIN938 Stud Bolts?

Send us your thread size, total length, material grade, surface treatment, and quantity. Our engineering team will confirm availability and issue a quotation within 24 hours. Standard stock ships in 3–5 business days worldwide.

Frequently Asked Questions

Common questions from buyers and engineers about DIN938 stud bolt specifications, ordering, and technical selection.

What is the difference between DIN938 and DIN939?

DIN938 has a screwing-in length of 1×d (one times the nominal diameter), suitable for steel and cast steel. DIN939 uses 1.25×d for softer materials like cast iron and aluminium alloys. Choose DIN938 when the threaded hole is in a material with tensile strength ≥ 400 N/mm² or hardness ≥ 200 HB.

What are the standard dimensions for DIN938 M16?

For M16 (pitch 2.00 mm): b1 = 16 mm (screwing-in end), b2 = 32 mm (nut end), x max = 4.00 mm, minimum total length = 55 mm. Available lengths typically range from 55 mm to 300 mm in 5 mm increments.

Can DIN938 stud bolts be made in stainless steel?

Yes. Standard stainless grades are A2-70 (304 SS) and A4-70 or A4-80 (316 SS). A4-80 is recommended for marine, chemical, or high-chloride environments. Stainless DIN938 studs are available from M6 to M36 in stock and M3 to M52 on custom order.

What parameters are needed for bulk ordering?

Please provide: (1) Thread size and pitch, e.g. M16×2.00; (2) Total length in mm; (3) Material grade, e.g. 8.8 / A4-70 / 42CrMo4; (4) Surface treatment, e.g. zinc plated / Dacromet; (5) Quantity and packaging requirements. We will confirm stock availability and issue a quotation within 24 hours.

What is the maximum size available for DIN938?

The DIN 938 standard covers thread sizes from M3 to M52. Our standard stock covers M6 to M36. Sizes from M3 to M5 and M42 to M52 are produced on custom order with a minimum lead time of 5–10 business days.

Is DIN938 the same as GB/T 901?

GB/T 901 is the Chinese national standard for equal-length double-end studs (bm = 1d), which is dimensionally equivalent to DIN 938 for the same thread size range. However, the material property class designations and inspection requirements differ slightly. For export projects requiring DIN compliance, specify DIN 938 explicitly and request EN 10204 3.1 material certificates.

What is the lead time for DIN938 stud bolts?

Standard stock sizes (M6–M36 in grade 8.8 and A2-70) ship within 3–5 business days. Custom specifications — including non-standard lengths, alloy steel grades (42CrMo4), and special surface treatments — require 7–15 business days. Express production is available for urgent orders; contact our sales team for availability.

What quality documents and certifications do you provide?

We supply EN 10204 3.1 material test certificates showing chemical composition and mechanical properties for every batch. Our factory holds ISO 9001:2015 quality management certification. Upon request we can also provide dimensional inspection reports, third-party SGS test reports, and RoHS compliance declarations for zinc-plated and Dacromet surface treatments.