Double End Studs
| Standard | DIN 938 / 939 / 835 / 940 · OEM |
|---|---|
| Material | 35CrMo / SCM435 / 42CrMo |
| Strength Grade | 8.8 / 10.9 / 12.9 |
| Size Range | M8-M48 |
| Surface Treatment | Black Oxide / Phosphate / Zinc Plated |
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Product Description
Product Description & Key Specifications
Double end studs are fasteners with threads on both ends and an unthreaded shank or defined center section between them. They are used in machinery housings, engine and powertrain connections, equipment bases, pump and compressor assemblies, construction machinery and vibration-loaded industrial joints where one end engages a tapped component and the other end is tightened with a nut.
The metal-end engagement length is the main difference: DIN 938 is approximately 1d, DIN 939 is approximately 1.25d, DIN 835 is approximately 2d and DIN 940 is approximately 2.5d. OEM drawings may also define custom thread lengths, center shank diameter, chamfers, wrench flats or installation features. Material options include 35CrMo, SCM435 and 42CrMo, with 8.8, 10.9 and 12.9 strength grades selected according to load and fatigue requirement.
Black oxide and phosphate finishes are common for machinery and controlled assemblies, while zinc plated finish is selected for general corrosion protection. Accurate RFQs should include diameter, overall length, metal-end thread length, nut-end thread length, pitch, grade, finish, tolerance, mating nut type and certificate requirements.
| Product type | Double end studs / machinery studs |
|---|---|
| Standards | DIN 938 (≈1d) / DIN 939 (≈1.25d) / DIN 835 (≈2d) / DIN 940 (≈2.5d) / OEM drawing |
| Material | 35CrMo / SCM435 / 42CrMo |
| Strength grade | 8.8 / 10.9 / 12.9 |
| Size range | M8-M48 |
| Common models | M8 x 40, M10 x 50, M12 x 70, M16 x 100, M20 x 120, M24 x 160, M36 by drawing |
| Thread type | Metric thread on both ends, engagement length by DIN or OEM drawing |
| Surface finish | Black oxide / Phosphate / Zinc plated |
| Matched hardware | Hex nuts, all-metal prevailing torque nuts and flat washers |
| Documentation | MTC, hardness report, dimensional report and PPAP-style documents on request |
Dimensions & SpecificationsDIN 938
Technical Drawing
Dimensional Table
| Parameter | M3 | M4 | M5 | M6 | M7 | M8 | M10 | M12 | M14 | M16 | M18 | M20 | M22 | M24 | M27 | M30 | M33 | M36 | M39 | M42 | M45 | M48 | M52 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| P | 0.5 | 0.7 | 0.8 | 1 | 1 | 1|1.25 | 1.25|1.5 | 1.25|1.5|1.75 | 1.5|2 | 1.5|2 | 1.5|2.5 | 1.5|2.5 | 1.5|2.5 | 2|3 | 2|3 | 2|3.5 | 2|3.5 | 3|4 | 3|4 | 3|4.5 | 3|4.5 | 3|5 | 3|5 |
| b1 | 3 | 4 | 5 | 6 | 7 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 | 25 | 30 | 32 | 35 | 38 | 42 | 45 | 48 | 52 |
| ds/max | 3 | 4 | 5 | 6 | 7 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 | 27 | 30 | 33 | 36 | 39 | 42 | 45 | 48 | 52 |
Engineering references
Technical resources
Review the applicable dimensions, drawing and standard relationship before confirming the ordered specification.02
Selection
Selection Advantages by Application
Engine and Powertrain Connections
High-strength 10.9 / 12.9 double end studs are used in engine covers, housings, manifolds and powertrain assemblies where repeatable stud engagement and nut-side service access are required.
Automotive and EV fastenersMachinery Housings and Equipment Bases
M12-M24 studs in 35CrMo, SCM435 or 42CrMo are common for pumps, compressors, gearboxes, machinery bases and equipment frames. Black oxide or phosphate finish is often selected for machinery use.
Industrial equipment fastenersConstruction Machinery and Vibration Joints
Double end studs can be paired with all-metal prevailing torque nuts for selected vibration-loaded equipment assemblies. Confirm thread engagement and locking nut compatibility before production.
Construction fasteners03
Assembly
Recommended Matching Products
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Manufacturing
Manufacturing & Quality Control
Manufacturing CapabilityQuality Control
Cutting, turning and centerless preparation for stud blanks35CrMo / SCM435 / 42CrMo material and heat number verification
Thread rolling or cutting on both ends by DIN / OEM drawingThread gauge, overall length and individual thread length inspection
Heat treatment for 8.8 / 10.9 / 12.9 mechanical gradesHardness, tensile and dimensional checks by lot when specified
Black oxide, phosphate or zinc plated finishCoating appearance, thickness and nut fit inspection after finishing
Bulk, tray or kit packaging for OEM and maintenance ordersMTC, CoC and inspection documents prepared according to RFQ
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FAQ
Common Questions Before RFQ
What is the difference between a double end stud and a fully threaded rod?
A double end stud has defined threads on both ends for tapped-hole engagement and nut-side tightening, while a fully threaded rod has continuous thread along its full length.
Which DIN standard should I choose?
Use DIN 938 for a metal-end engagement of approximately 1d, DIN 939 for 1.25d, DIN 835 for 2d and DIN 940 for 2.5d. The final choice depends on the tapped material, joint design and drawing requirement.
Can double end studs be made to OEM drawings?
Yes. Custom overall length, thread length, shank diameter, chamfers, wrench flats and special tolerances can be produced from drawings.
Which finish is suitable for machinery studs?
Black oxide and phosphate are common for machinery assemblies, while zinc plated finish is used where general corrosion protection is required.
Can lock nuts be supplied with the studs?
Yes. Double end studs can be supplied with hex nuts, all-metal prevailing torque nuts and washers when the assembly requirement is confirmed.
Need double end studs to DIN or OEM drawings?
Send diameter, overall length, thread lengths, grade, material, finish, matching nut requirement and drawing tolerance. We can quote DIN 938 / 939 / 835 / 940 and OEM double end studs for machinery and equipment assemblies.
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