Property Class 12.9 Steel Inch Left-Hand Fully Threaded Rod are supplied to ISO 898-1 property class 12.9. Corrosion behaviour is requires plating or black-oxide protection, the material is magnetic, and the usable service range is commonly limited to approx. +300 °C; confirm against the coating and the load. In practice this grade is the highest common strength class, for high-load machine assembly.
- Grade
- ISO 898-1 property class 12.9
- Corrosion resistance
- Requires plating or black-oxide protection
- Magnetic response
- Magnetic
- Service temperature
- commonly limited to approx. +300 °C; confirm against the coating and the load
Property values are typical for the grade. Certified mechanical test data is available on request for production orders.
Material specification page for inch left-hand fully threaded rod in Property Class 12.9 Steel. Covers the grade designation (ISO 898-1 property class 12.9), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to ASME B18.31.3 and ASME B1.1 LH.
Why Choose Property Class 12.9 Steel for Inch Left-Hand Fully Threaded Rod
The highest common strength class, for high-load machine assembly. For inch left-hand fully threaded rod, this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 12.9 |
|---|
| Magnetic response | Magnetic |
|---|
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
|---|
| Corrosion characteristic | Requires plating or black-oxide protection |
|---|
Corrosion Behavior in Service
Carbon and alloy steel inch left-hand fully threaded rod require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Comparable Grades
For Inch Left-Hand Fully Threaded Rod, class 8.8 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.
Sizes of Inch Left-Hand Fully Threaded Rod Available in Property Class 12.9 Steel
| Nominal size | Thread hand | Thread class | Standard lengths (in/ft) | Material options | Reference standard |
|---|
| 6-32 | left-hand | 2A | 12 / 24 in and 3 ft | zinc-plated steel / 18-8 stainless / 316 stainless | ASME B18.31.3 and ASME B1.1 LH |
| 8-32 | left-hand | 2A | 12 / 24 in and 3 ft | zinc-plated steel / 18-8 stainless / 316 stainless | ASME B18.31.3 and ASME B1.1 LH |
| 10-24 | left-hand | 2A | 12 / 24 in and 3 ft | zinc-plated steel / 18-8 stainless / 316 stainless | ASME B18.31.3 and ASME B1.1 LH |
| 1/4-20 | left-hand | 2A | 12 / 24 in and 3 ft | zinc-plated steel / 18-8 stainless / 316 stainless | ASME B18.31.3 and ASME B1.1 LH |
| 3/8-16 | left-hand | 2A | 12 / 24 in and 3 ft | zinc-plated steel / 18-8 stainless / 316 stainless | ASME B18.31.3 and ASME B1.1 LH |
| 1/2-13 | left-hand | 2A | 12 / 24 in and 3 ft | zinc-plated steel / 18-8 stainless / 316 stainless | ASME B18.31.3 and ASME B1.1 LH |
Applications & Industries
Where Inch Left-Hand Fully Threaded Rod are used, and what decides the specification in each case. Stocked from 6-32 to 1/2-13 (screw size).
Industries that specify Inch Left-Hand Fully Threaded Rod
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Opposed adjusters
Left-hand and right-hand rod pairs used to change length without disconnecting the joint.
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Rotating equipment
Threaded adjustments arranged to resist self-loosening in service.
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Machine fixtures
Inch adjustment rods where the thread hand is part of the mechanism.
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Repair and fabrication
Replacement rod matched to existing left-hand nuts and couplers.
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Pressure equipment & flanges
Studs and nuts on flanged joints, where both ends are tightened and the assembly is inspected.
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Plant & machine installation
Anchoring and levelling machines onto bases and frames.
Typical applications
- providing a left-hand threaded member for an opposed adjuster
- matching the rod to a left-hand nut rather than a standard right-hand nut
- holding a threaded adjustment against rotation in a paired mechanism
- specifying inch thread class, hand, length and material together
- clamping a joint from both ends where a headed bolt will not fit
- suspending services from a soffit on threaded rod
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- High load
- Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
Where to use something else
- Do not pair a left-hand rod with an ordinary right-hand nut; the threads will not engage correctly.
- Not for a joint that must be tightened from one side only — there is no head to hold.
Full application guide: where Inch Left-Hand Fully Threaded Rod are used, how to specify them, and the cases they are wrong for
