User's Guide — 45
Hip/Valley & Jack Rafters
The Construction Master IV uses the
rise, run, diagonal, pitch and o.c.
spacing values to compute regular
(45°) and irregular (non-45°) hip/
valley and jack rafter lengths (ex-
cluding wood thickness, etc.).
“Regular” Hip/Valley & Jack Rafters:
To solve for regular (45°) hip/valley
and jack rafter lengths, press [Hip/V]
and then [Jack]. Repeated presses of
[Jack] will compute all regular jack
rafters – from longest to shortest size.
“Irregular” Hip/Valley & Jack Rafters:
To solve for irregular (non-45°)
hip/valley and jack rafter lengths, en-
ter the irregular pitch using [Conv]
[Hip/V] (10 [Inch] [Conv] [Hip/V]).
Press the [Hip/V] key again to find the
length of the irregular hip/valley raf-
ter. Then press [Jack] to compute the
size of the longest irregular jack rafter
on the common pitch side. Successive
presses of [Jack] will display each de-
creasing jack size.
