Set square adapted for production of extended lines of right angle, comprises square supports, cord carrying guide block at square apex and two sighting blocks at square extremities

摘要

The square is supported by sliding frames (8) which have adjustable feet with bolt holes (6) and tightening screws (9). At the apex of the square a guide block (2) with bolt hole (7) supports a string by V notches (3). Sighting blocks with guide notches (4) are aligned with the guide block V notches such that when the string is tensioned and positioned it defines two sides of a right angle for any desired length.