Square Nut

Square Nut is the nut for pole-line machine bolts, double arming bolts, carriage bolts and spool bolts. Its broad square faces bear on the washer at the back of the pole and give the lineman's wrench a firm grip. It is tapped oversize to run on galvanized threads. Specify bolt size and the quantity you need.

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At a glance

Square Nut at a glance.

Function

Tightens the pole-line bolt

The square nut goes on the back of the through bolt and clamps the crossarm or fitting to the pole.

Galvanized thread

Tapped oversize

The nut is tapped oversize so it runs freely on a hot dip galvanized bolt thread without stripping the zinc.

Product form

3/16 to 1 1/4 in, M6 to M32

3/16–1 1/4 in (M6–M32) bolt sizes, UNC thread, to ASME B18.2.2 and ANSI C135.1, hot dip galvanized to ASTM A153.

Also known as

Spanish-speaking crews call it tuerca cuadrada.

Español (US): tuerca cuadrada

Trade names for the whole range ↗

How it works

Washer, nut, then wrench

With the bolt through the pole, a square or curved washer goes on the back and the square nut is run up the thread. It is tightened with a lineman's wrench until the fitting is clamped, and the square corners hold the wrench on the nut.

Common applications

Where it is used.

Application

Crossarm through bolts

Every square-head machine bolt in a crossarm assembly takes a square nut. The nut matches the head pattern of the bolt.

Application

Double arming bolts

Each double arming bolt carries four nuts, one each side of each arm. Square nuts are the usual choice on North American lines.

Application

Carriage and spool bolts

Carriage bolts for braces and spool bolts for insulators are fixed with square nuts. The same galvanized nut serves each.

What else is a square nut called?

In Spanish it is a tuerca cuadrada.

Why are pole-line nuts tapped oversize?

Hot dip galvanizing adds a layer of zinc to the bolt thread. Nuts are tapped oversize so they run on freely without stripping the coating. Square nuts are tapped this way in 3/16 to 1 1/4 in (M6 to M32) sizes and galvanized to ASTM A153.

Pole-Line Assemblies