Manual

User's Guide — 75
Irregular (non-45°) Hip/Valley and Jack Rafters —
Ascending, with Jacks Mating at Hip/Valley (not
available on LT)
You’re working with a 7/12 pitch and half your overall span is 4 feet.
The irregular pitch is 8/12, and the Jacks need to mate at the Hip. The
maximum allowable on-center spacing is 16 inches. Find the Jack raf-
ter sizes from smallest to largest (ascending order). Complete the fol-
lowing steps:
(1) Set Preference display to “JK ASCEND” (Jack sizes in ascending
order);
(2) Set Preference display to “IRJK JAC-JAC” (Jacks mate);
(3) Find the length of the Common rafter;
(4) Find the length of the adjoining “irregular” Hip (or Valley) and the
cut angles;
(5) Find the o.c., Jack lengths and cut angles on the “irregular”
pitched side;
(6) Find the o.c., Jack lengths and cut angles on the “regular” pitched
side.
þþ Note: After completing this example, you may need to reset the Pref-
erences back to “IRJK OC-OC” if you do not normally figure Jacks in
this manner. (See Preference Settings on page 96.)
Keystroke Display
1. Review Preferences until you find “Jack Descend”:
[On/C] [On/C] 0.
[Conv] [Stor] FRAC 0-1/16 INCH
(If not at 1/16, press [+] until 1/16 is displayed)
[Stor] AREA Std.
[Stor] VOL Std.
[Stor] RAKE dESCEnd
[Stor] JACK dESCEnd
Set Preference to “Ascend”:
[+] (plus sign) JACK ASCEnd
2. Set Preference to “Jacks Mate”:
[Stor] IRJK OC-OC
[+] (plus sign) IRJK JAC-JAC
(Cont’d)