T-SQUARES & PARALLEL RULES
T
-Squores
T-squares are straightedges that have ashort
crosspiece at one end. This head slides along the
edge of adrawing board as aguide in establishing
and drawing straight parallel lines. T-squares are
relatively low incost and portable but require a
straight and true edge against which their heads
can slide.
• This end of aT-square is subject to wobbling.
• T-squares are available in 18", 24", 30", 36",
42", and 48" lengths. 42" or 48" lengths are
recommended.
• Ametal angle secured to the drawing board
can provide atrue edge.
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Use this length of the straightedge.
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• •
• T-squares with clear, acrylic straightedges
should not be used for cutting. Metal
T-squares are available for this purpose.
Rollers enable the parallel rule to move freely
across adrawing surface.
Transparent, acrylicedges are recommended
for better visibility while drawing lines. Some
models are available with metal cutting edges.
Parallel Rules
Parallel rules are equipped with a system of cables
and pulleys that allows their straightedges to
move across adrawing board only in a parallel
manner. Parallel rules are more expensive and less
portable than T-squares but enable one to draft
with greater speed and accuracy.
Parallel rules are available in 30", 36", 42", 48",
54", and 60" lengths. The 48" length is
recommended.
DRAWING TOOLS & MATERIALSI 5