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Section 4 Finishing
Splitting angles for miter cuts
The carpenter sometimes faces odd angles that
must be accurately split to make a miter cut. This
can be mathematically calculated, but the following
method avoids the math and assures great accuracy.
1. Select a plywood scrap about 6″ wide and 1′ long
with a factory edge to use as a storyboard.
2. Draw a line near to and parallel with the factory
edge.
3. Use a T-bevel to fi nd the angle to be mitered and
transfer the angle to the storyboard.
4. Draw a line along the blade of the T-bevel, as
shown in Figure 18-24A.
5. Open a pencil compass or scribe about 3″ to 4″.
Place the point of the instrument at the intersec-
tion of lines AB and AC and draw arcs of equal
length across both lines, Figure 18-24B.
6. Swing arcs of equal distance from points B and C
to create point D, Figure 18-24C. You may need
to open up the compass or dividers somewhat
more to create this point.
7. Draw a line to connect points A and D, Figure
18-24D. This is the miter angle.
8. Adjust the T-bevel to this angle and use it to set
the miter saw.
9. Make a test cut on scraps to verify the accuracy
of the angle.
Splitting angles for miter cuts
The carpenter sometimes faces odd angles that
must be accurately split to make a miter cut. This
can be mathematically calculated, but the following
method avoids the math and assures great accuracy.
1. Select a plywood scrap about 6 ″ wide and 1 ′ long
with a factory edge to use as a storyboard.
2. Draw a line near to and parallel with the factory
edge.
3. Use a T-bevel to fi nd the angle to be mitered and
transfer the angle to the storyboard.
4. Draw a line along the blade of the T-bevel, as
shown in Figure 18-24A.
5. Open a pencil compass or scribe about 3 ″ to 4 ″ .
Place the point of the instrument at the intersec-
tion of lines AB and AC and draw arcs of equal
length across both lines, Figure 18-24B.
6. Swing arcs of equal distance from points B and C
to create point D, Figure 18-24C. You may need
to open up the compass or dividers somewhat
more to create this point.
7. Draw a line to connect points A and D, Figure
18-24D. This is the miter angle.
8. Adjust the T-bevel to this angle and use it to set
the miter saw.
9. Make a test cut on scraps to verify the accuracy
of the angle.
Figure 18-24. Splitting an angle for a miter cut. A—After drawing a line parallel to the factory edge, transfer the
miter angle to the board. B—Draw arcs of equal lengths from the intersection of lines AB and AC. C—Swing arcs
to create point D. D—Draw line AD. This is the miter angle.
Line parallel
factory edge
Draw pencil line to
intersect parallel line
A
A
D
B
C
C
B
A
C
B
D
B
C
A
D