Guy Anchor and Anchor Rod Specifications: What to Put in Your RFQ

A specification for guy anchor and anchor rods is only useful if it is unambiguous to someone who cannot see your project. Most disputes on this product do not come from bad manufacturing — they come from a drawing that could reasonably be read two ways, where the supplier read it the cheap way and the buyer read it the expensive way.

This is a practical specification checklist, written around what the standards actually require.

The three specification families you will meet

Suppliers will quote against whichever family your market uses, and the part can usually be built to any of them:

• ANSI C135.1 — Galvanised ferrous pole line hardware.
• ASTM A153 — Zinc coating weights on hardware.

The mistake is to specify a standard reference without specifying the class or grade within it. If you write only the standard number, the supplier will quote the lowest class that satisfies it. Write the standard and the level you want.

Dimensional data that has to be on the drawing

For this product the critical dimensions are: rod diameter 16–32 mm, lengths 1.2–3.0 m, screw anchors 150–400 mm helix diameter.

Three rules that prevent most dimensional disputes:

1. Give tolerances on every functional dimension, not just the nominal values. A nominal dimension with no tolerance is legally “as the supplier chooses”.
2. Say which dimensions are functional and which are cosmetic. Suppliers prioritise what you prioritise, and they cannot guess.
3. State the gauge or measuring method where a dimension is critical. Two inspectors with different methods will disagree about the same part.

Material and grade

The base specification is forged or cast steel, hot-dip galvanised. Grades commonly offered include:

• Q235B forged rod
• ductile iron anchor head
• 45# steel for high-load rods
• galvanised 70–100 µm

Ask the supplier to state the grade on the quotation, not on an assumption. Grade substitution is the single most common silent cost reduction, and it is usually invisible in the finished part — a 201 stainless component looks exactly like a 304 one until the second winter.

Surface treatment

The usual finish for this product is hot-dip galvanised 70–100 µm, rolled thread preserved through coating, anchor head cast or forged.

Two points worth writing into the order:

• A measured requirement, not a process name. “Hot-dip galvanised” is a process; “70 µm minimum, tested by coating mass on three parts per batch” is a requirement.
• What happens at cut edges and drilled holes, if any. These are where coatings are habitually broken and where corrosion starts.

Type tests and routine tests

These are different things and are frequently confused in quotations:

• Type tests qualify the design once. On this product: pull-out test where specified; tensile proof load on the rod; coating mass.
• Routine tests are run on every batch: thread gauge check.

Specify which type-test reports you want supplied as documents, and which routine test results must accompany each shipment. On a first order, ask for the type-test report before you place it.

The failure modes your specification should be closing

• Thread damage during driving — no protective cap and a rod driven with a hammer rather than by the head
• Anchor pulling out in service — an anchor chosen from the catalogue rather than from a soil assessment — the anchor is only as good as the ground it sits in

Each of these can be turned into one line in the specification. That is the real purpose of writing it out: not bureaucracy, but making the specific failure you are worried about somebody’s explicit responsibility.

A specification skeleton you can reuse

1. Scope: Guy Anchor and Anchor Rod to be supplied as guy anchor, screw anchor, anchor rod, expanding anchor.
2. Dimensions and tolerances: rod diameter 16–32 mm, lengths 1.2–3.0 m, screw anchors 150–400 mm helix diameter.
3. Material: forged or cast steel, hot-dip galvanised; grade Q235B forged rod or better.
4. Standard: ANSI C135.1 — Galvanised ferrous pole line hardware; ASTM A153 — Zinc coating weights on hardware.
5. Finish: hot-dip galvanised 70–100 µm, rolled thread preserved through coating, anchor head cast or forged.
6. Tests: pull-out test where specified; tensile proof load on the rod; coating mass; thread gauge check.
7. Marking and packing: bundles per size, threads capped.
8. Inspection: pre-shipment, against this specification, with photo evidence and test records.

Related: the guy anchor and anchor rod quality inspection checklist turns this specification into an inspection plan you can hand to a third-party inspector.