Bandmill Saws - Gullet Area

ga = tp × gd × gaf

ga = gullet area (square inch)
tp = tooth pitch (inch)
gd = gullet depth
gaf = gullet area factor (.42 for square back tooth .52 for round back tooth)

Bandmill Saws - Tooth Bite
tb = (fpm × 12) ÷ ((bwd × 3.1416 × rpm) ÷ tp)

tb = tooth bite (inch)
fpm = feed speed (fpm)
bwd = wheel diameter (in.)
rpm = arbor rpm
tp = tooth pitch (inch)

Bandmill Saws - Gullet Capacity

gc = ga ÷ sef

gc = gullet capacity (square inches)
ga = gullet area (square inches)
sef = sawdust expansion factor

Sawdust Expansion Factor:

• 1.8 to 2.0 for slow growing species (ie. Northern Spruce)
• 2.5 for fast growing species (ie. Southern Yellow Pine)

Bandmill - Saw Speed

bs = (bwd × 3.1416 × rpm) ÷ 12

bs = blade speed (feet / minute)
dwd = wheel diameter (in.)
rpm = arbor rpm

Bandmill - Horsepower

hp = fpm x doc x kf x sg x 100 ÷ 144 ÷ ade x 100

hp = estimated power required (hp)
fpm = feed speed (fpm)
doc = depth of cut (inch)
kf = kerf (inch)
sg = Specific Gravity
144 = 12 inch/feet squared
ade = arbor drive efficiency %

Specific Gravity:

• Spruce = .35
• Douglas Fir = .45
• SYP = .47
• Oak = .60

Bandmill Saws - Gullet Fill Percentage

gf% = (doc × tb) ÷ (ga ÷ sef) × 100

gf% = gullet fill %
doc = depth of cut 
tb = tooth bite
ga = gullet area (sq. inches)
sef = sawdust expansion factor

Sawdust Expansion Factor

• 1.8 to 2.0 for slow growing species (ie. Northern Spruce)
• 2.5 for fast growing species (ie. Southern Yellow Pine)