Speed square

From Wikipedia, the free encyclopedia

SPEED® Square – trademark – is a three-sided, triangular shaped measuring tool manufactured by Swanson Tool Co., Inc. that is used to draw perpendicular lines on boards to be cut or to lay out angles for roofs, stairways, decks and other general construction. Another name is a rafter angle square; it's marked with degree gradations for fast layout. The square's small size makes it easy to store and transport.

[edit] Specific uses of Square

It is used to cut Common, Hip, Valley and Hip or Valley Jack rafters, layout stringer in stair fabrication, mark angles, determine angles and to square off boards to mention a few uses. It serves as a convenient straightedge and guide for circular saws and should be clamped when cutting splayed angles for user safety.

[edit] Operation of Square

At the intersection of the two sides of the triangle there is a pivot point which is clearly marked. The pivot point is placed on the edge of the board and the square is moved to the desired hip, valley, common rafter or degrees scale on the board and marked accordingly. The intersection of the pivot point and where the readings coincide on the board determines the pitch or angle. The 12 inch square can be used to lay out stairs.