Bosch GCM12SD Operating/Safety Instructions Manual page 37

BM 2610007877 08-10:BM 2610007877 08-10.qxp 8/24/10 1:05 PM Page 37
pitch angle information – The top section of the
miter scale shows angle settings required to cut roof
rafters to the "Pitch Angle" system. 2/2, 4/12, 6/12,
etc., are all pitch angles. This system is based on
using the English "inches." A 6/12 pitch angle roof
equals a ratio of 6" "rise" for every 12" "run" (see
Figure 45).
Crown molding information – There are miter
position settings for compound-cutting crown molding
flat on the table. Crown molding with 38° "spring
angle" uses the 31.6 setting (with detent) and crown
molding with 45° "spring angle" uses the 35.3 setting.
NOTE: This cutting method also requires that specific
bevel angles are set – see Cutting Crown Molding on
page 45.
Saw Operations
Miter Cuts
12
RISE
12 RUN
12/12
figure 45. pitch Angle Cutting – Common Roof Rafters
37.
6
RISE
12
RUN
6/12