Johnson Level & Tool Mfg. RAS-1 - Manual (Page 33)

31
STEP 2. LAYOUT STRINGER: First, find the step incline
length (see Figure 18) by using the following formula:
STEP INCLINE
= (STEP RISE) 2 + (STEP RUN) 2
In our example:
STEP RISE = 7.29
STEP RUN = 10.21
USING THE FOLLOWING INCLINE FORMULA:
STEP INCLINE = (7.29) 2 + (10.21) 2
= (53.14) + (104.24)
= 157.38
= 12.545
NOTE: The symbol is the square root symbol.
Second, find the stringer incline length by using the
following formula:
Stringer Incline Length =
Step Incline Length x (number or steps – 1)
In our example:
Stringer Incline Length = 12.545 x (14 – 1)
= 12.545 x (13)
= 163.085 Inches
= 13 ft. 7-1/16 Inches
NOTE: Table B on Page 30 shows the inch decimal to inch
fraction conversion.