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Chapter 9 Flatness Measurements
Setting Up for the Measurement
Drawing the perimeter lines of the measurement grid
Although you have already approximated the border for your
measurement, in this section you draw the lines that define the actual
border for your measurement (lines 3 through 6). To correctly draw the
measurement grid, you must first draw the perimeter lines of the
measurement grid. To do so, refer to Figures 9-3 and 9-4, and follow these
steps:
1
Use the foot spacer to mark stations on the straightedge.
You can then use the straightedge to mark these stations on the surface
plate. Remember, the size of the interval is the distance between the
scribe lines on the foot spacer you chose.
2
Using a straightedge and a pencil or chalk, draw a perimeter line on the
side closest to the surface plate's nameplate (Line 3).
Be sure to leave the correct size border between the line and the edges of
the surface plate.
3
Mark the foot spacer stations on the line by following these steps:
a. Mark the midpoint of Line 3 (Point B).
b. Align the center of the straightedge with this midpoint.
c. Starting at the midpoint, mark your measurement stations in both
directions on the line.
Remember, the size of the intervals is the distance between the scribe
lines on the foot spacer you chose.
Do not mark within your border. If marking a station extends the line
into the border between the measurement grid and the edge of the
surface plate, the previous station is now the end of the line (points A
and C).
Note the number of stations marked.
d. Mark the end points of Line 3.
9-10
Measurements Reference Guide
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