Double-Ended Stud

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A Double-Ended Stud is a rod-shaped fastener with threads at both ends and a shank (or full threads) in the middle, featuring no head structure. It relies on nuts at both ends for connection and fixation. Its typical structure includes:

• Threaded segments at both ends, which can be of equal or unequal lengths (e.g., one end for screwing into a threaded hole, the other for nut installation);

• The shank diameter in the middle usually matches the nominal thread diameter to ensure overall strength.

Core Characteristics

• Connection Flexibility: Requiring no head space, it can pass through through-holes or screw into blind holes, suitable for space-constrained scenarios.

• Uniform Force Distribution: Symmetrically loaded at both ends, ideal for applications with high axial loads (e.g., flange connections).

• Easy Disassembly: Only nuts need to be unscrewed during disassembly, while the stud remains in the fixed part for convenient reinstallation.

Main Applications

• Mechanical Engineering:

• Flange connections (e.g., pipe flanges, pressure vessels), where the stud penetrates flange holes and is clamped by nuts at both ends for sealing.

• Fixing bases of motors, pumps, etc., or connecting bearing blocks to supports.

• Construction/Bridges:

• Embedded part connections (e.g., steel structure joints, curtain wall supports), with one end embedded in concrete and the other end connecting components.

• Automotive/Aerospace:

• Engine cylinder head bolts, wheel hub fixing bolts, etc., achieving high-strength connections via the double-ended structure.

Common Materials and Standards

• Materials:

• Carbon steel (Classes 4.8, 8.8): For general mechanical connections;

• Alloy structural steel (Classes 10.9, 12.9): For high-strength scenarios (e.g., high-pressure pipelines);

• Stainless steel (304, 316): For corrosive environments.

• International Standards:

• Metric: ISO 8734 (double-ended studs), GB/T 897-900 (Chinese standards);

• Imperial: ASME B18.31.1 (U.S. standards).

Selection and Installation Tips

• Length Calculation:
  Total length = Length of the screwed-in end (b₁) + Shank length + Length of the nut end (covering nut thickness + washer + allowance).

• Screwed-in End Design:

• For cast iron parts: b₁ = 1.25d (d = thread diameter);

• For steel parts: b₁ = d.

• Anti-loosening Measures:
  Use locknuts (e.g., nylon insert locknuts) or threadlocker (e.g., Loctite) in vibrating scenarios to prevent loosening.