These are heavy-duty industrial tools known as ‘Leader’ pipe wrenches. They are used in civil engineering and are consequently made to conform to the most stringent specifications.
The cast iron handle is a heavy ‘I’ beam construction to ensure maximum strength and rigidity under loading. The teeth on each jaw are hardened and tempered to resist wear. The design of this wrench allows a bigger jaw capacity than the ‘Stillson’ wrench. The lower jaw is precision seated to prevent harmful loading onto the retaining pin.
Conforms to BS3594 part 1.