Sample
60
Part C
■
Framing
■
EXAMPLE 6.1
A common rafter rises 5
⬘
-4
⬙
in a run of 14
⬘
-2
⬙
. Find (a) the pitch of this
rafter in inches, (b) its pitch in degrees and (c) its slope.
Solution:
KEYSTROKE
DISPLAY
(a) (b) (c) Following the procedures outlined in Chapter 2, enter the given
data as shown, and solve for the pitch:
5 f 4 i r
RISE 5 FEET 4 INCH
1 4 f 2 i R p
PTCH 4-1/2 INCH
p
PTCH 20.63°
p p
SLP 0.376471
Your
Construction Master Pro
calculator can also provide the point-to-point
rafter length (excluding ridge adjustment or overhang) for common rafters, as
well as the angles, in degrees for making
plumb
(vertical) cuts, and
level
(hor-
izontal) cuts as shown in
Figure 6-2.
These angles may be used for fitting
rafter to ridge; cutting a
bird’s mouth
to seat a rafter on the top plate; or trim-
ming rafter tails to accept fascia and soffit boards.
■
EXAMPLE 6.2
For the rafter of Example 6.1, find the rafter length, and angular values for
plumb and level cuts.
Solution:
KEYSTROKE
DISPLAY
Enter the data for rise and run as before:
5 f 4 i r
RISE 5 FEET 4 INCH
1 4 f 2 i R
RUN 14 FEET 2 INCH
d
DIAG 15 FEET 1-5/8 INCH
d
PLMB 20.63°
d
LEVL 69.37°
Using the capabilities built into your
Construction Master Pro
calcu-
lator, it is possible to determine all information related to common rafters
for any specified framing conditions. Three of the situations most fre-
quently encountered by builders are these:
1.
Given the
rise
and
run,
determine the pitch and rafter length.
2.
Given the
pitch
and
rise,
find the run and rafter length.
3.
Given the
pitch
and
run,
calculate the rise and rafter length.
Notes
Construction Master® Pro Workbook and Study Guide
Copyright © 2007 by Calculated Industries, Inc.
and Thomson Delmar Learning
Calculator Tip
Pitch Display Order:
Order of answers
displayed varies
depending on last
format of pitch entered.
Continue pressing
p
until desired format is
displayed.
Calculator Tip
Power User Tip:
Displayed pitch results
will start with the last
entered pitch format.
For example, if
7 i
p
is entered, any
future pitch calculation
will begin with the pitch
in inch format, unless
calculator is reset.
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