Military Stud Bolts — Continuous Thread & Double-End
Stud bolts have no head — a headless, externally threaded rod driven into a tapped hole on one end and torqued with a nut on the other, primarily used in naval high-pressure flanges, engine manifolds, and other applications where two mating parts need to be drawn together without a bolt head protruding on the blind side.
Stud Bolt Configurations We Manufacture
Type I — Full Body
Continuous major diameter shank along the full stud length, providing maximum shear cross-section.
Type II — Reduced Body
Shank diameter reduced below the thread root diameter for weight savings or improved fatigue performance.
Type III — Constant Strength
Shank diameter proportioned so the shank and thread root have matched tensile strength, avoiding a weak point at either section.
Type IV — Continuous Thread
Threaded along the entire stud length, allowing the nut position to be adjusted anywhere along the stud's length.
Overview
Stud bolts are the fastener of choice wherever a bolt head can't be accommodated — most commonly in high-pressure piping flanges, pump and valve bodies, and engine manifolds, where one end of the stud is torqued into a tapped hole in the base component (the "stud end") and the other end receives a nut to draw the mating flange or cover down.
MIL-DTL-1222 defines the standard configuration matrix: four stud body types (full, reduced, constant-strength, and continuous thread) and four thread-class "styles" (A through D) that pair different thread classes on the stud end versus the nut end, letting engineers balance installation reliability into the tapped hole against a precise fit for the mating nut.
- Stud material and finish follow the same high-reliability qualification path as MIL-DTL-1222 bolts and nuts, since studs are covered under the same general specification.
- Double-end studs are torqued in with a stud driver or two jam nuts, since there's no bolt head to grip directly.
Applicable Standards
Explore the individual military stud bolt specifications Ananka manufactures to.
Military Stud Bolts — Frequently Asked Questions
What's the difference between a stud bolt and a regular bolt?
A stud bolt has no head — it's threaded into a tapped hole in one component and draws a second component together using a nut on the opposite end, whereas a standard bolt has an integral head that bears directly against the top part.
How is a double-end stud installed without a bolt head to grip?
Typically with a dedicated stud driving tool, or by running two jam nuts together onto the stud end and using the outer nut to torque the stud in — a common shop technique often called "double-nutting."
What does "constant strength" body mean?
Type III studs under MIL-DTL-1222 have their shank diameter proportioned so the plain shank section and the reduced thread-root section have matched tensile strength — avoiding a weak point that could fail preferentially under load.
Need Military Stud Bolts to Print?
Ananka Fasteners manufactures MIL-DTL-1222 stud bolts with full material traceability and Mill Test Certification on every lot.
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