6.4.1 Precision Layout Tools
Precision layout tools are used when greater
precision is needed to produce a layout. They
commonly include Vernier-type measuring tools,
which were discussed in Chapter 5. See Figure 6-22.
These measuring and gaging tools are used to
draw lines when specifications call for locations
to be accurate to within 0.001″ (0.025 mm).
6.4.2 Surface Plate
A precise, flat surface is required for accurate
layout work to be accomplished. A surface plate,
Figure 6-23, is most frequently used to inspect the
flatness of layout work surfaces. Most surface
plates made today are produced from granite,
which is very stable and not affected greatly by
changes in temperature.
Surface plates are primarily designed for
layout and inspection work. They should never be
used for any task that could mar or nick the
surface.
6.4.3 Right Angle Plate
The right angle plate is used when a square
reference surface is needed. See Figure 6-24. The
Chapter 6 Layout Work 103
Figure 6-20.
The blade on a universal bevel is adjustable and can be
used to lay out and transfer angles. (L. S. Starrett Co.)
Figure 6-21.
A Vernier protractor is employed to make precise
angular measurements. In this application, a protractor
is mounted on a height gage. (L. S. Starrett Co.)
Figure 6-22.
Precision layouts can be made with Vernier height
gages and other Vernier measuring tools.
(L. S. Starrett Co.)
Figure 6-23.
Most surface plates today are made from pink or
black granite. Changes in temperature have less of an
effect on granite surface plates compared to older
semisteel surface plates. (L. S. Starrett Co.)