Multi-purpose Triangle Square (12"/300mm)

The size first. Twelve inches spans wider material than a seven inch square, which matters on wide boards, sheet material and larger framing where a small square registers on too little of the edge to be reliable. It also gives a longer edge to run a saw against, and a longer guide produces a straighter cut.

The adjustable stainless steel ruler is the significant addition. It slides and locks, so the tool works as a marking gauge — set the rule to a distance, hold the square against the edge and run it along with a pencil at the rule's end, and you scribe a line parallel to that edge down the whole length of a board. That is a job people usually do badly with a tape and a series of pencil ticks, and it is exactly how a rip line or a rebate line should be marked.

The built-in vial adds a spirit level for short work — checking a rafter, a stud or a fixing without fetching a separate tool.

The body is carbon steel rather than the aluminium of the smaller square. Steel is stiffer and much harder, so the edge resists the nicks that a circular saw blade inflicts on an aluminium square — a genuine advantage for a tool used as a saw guide. The trade is weight and the fact that carbon steel will rust if it is left wet, so it wants wiping and an occasional light oil. The handle is nylon.

The buyers are carpenters and framing joiners, roofing and stair carpenters, shopfitters, formwork carpenters, building contractors, and hardware dealers supplying site trades.

Two habits. Lock the sliding rule firmly and check it has not crept before marking a long line, because a rule that slides mid-stroke gives a tapering line rather than a parallel one. And check the right angle with the flip test after any drop: hook the square on a straight edge, scribe along the arm, flip it and scribe again from the same point — the lines should coincide. Message us on WhatsApp for a price.