46 — Construction Master IV
Additional presses of [Jack], once
“0” is reached, will cause your calcu-
lator to “revolve,” or display the rafter
sizes on the opposite side of the
hip/valley rafter (i.e., the Irregular
Pitch Side). Pressing [Conv] [Jack]
will start the display sequence using
the longest rafter size on the irregular
pitch side.
Hip Rafter
Jack Rafters
16”
Common
Side
[Jack]
Irregular
Side
{I/Jack}
When calculating regular and ir-
regular jack rafter lengths, you will
see the letters “JK” (common pitch)
or “IJ” (irregular pitch) with the cor-
responding Jack number to the left of
your calculator display. This will en-
able you to keep track of the de-
scending sizes, and which side the
corresponding rafter is based on.