The saw formulas presented are based on imperial measurements:

 Power:

Power (hp) required is a function of feed speed, saw design and specific gravity of the wood being sawn.  Increasing any of the variables will increase the horsepower required.

• Feed Speed [fpm] x Depth of Cut [inches] x Kerf [inches] x Specific Gravity x 100 ÷ 144 ÷ Arbor Drive Efficiency x 100
• Specific Gravity: Douglas Fir = .45, Oak = .60, Southern Yellow Pine = .47, Spruce = .37, Oak = .60

 Feed Speed:

Feed Speed (fpm) constrains is a function of horsepower, saw design and specific gravity of the wood being sawn.  Increasing any of the variables will increase the feed speed constraint.

• Minimum (Max Feed Speed [fpm], Horsepower ÷ Depth of Cut [inches] ÷ Kerf [inches] ÷ Specific Gravity ÷ 100 x 144 x Arbor Drive Efficiency ÷ 100, Gullet Area [sq. inches] ÷ Sawdust Expansion Factor ÷ Depth of Cut [inches] x (Surface Speed [fpm] ÷ Tooth Pitch [inches])
• Specific Gravity: Douglas Fir = .45, Oak = .60, Southern Yellow Pine = .47, Spruce = .37, Oak = .60

 Saw Surface Speed:

Saw surface speed (fpm) is the speed of the saw blade.  This is determined by the rpm of the abor and the diameter of the wheel.  The faster the saw speed the more teeth per minute in the cut.

•  Band Wheel Diameter × 3.1416 × Wheel RPM ÷ 12

 Tooth Bite:

Tooth bite is determined by the feed speed, the rpm of the saws and the number of teeth.  Increasing the feed speed will increase the tooth bite.

• Feed Speed [fpm] ÷ Saw Surface Speed [fpm] × Tooth Pitch [inches]

 Gullet Area:

Gullet area determines the amount of sawdust that the gullet will hold.  Increasing gullet size (with the same number of teeth) will allow the saw to be fed faster.

• Tooth Pitch [inches] × Gullet Depth [inches] × Gullet Area Factor
•  Gullet area factor = 0.42 for square back tooth 0.52 for round back tooth.

Gullet Capacity:

Gullet capacity is a function of gullet area and sawdust expansion factor.  Fast growing species such as southern yellow pine take up more gullet space due to the size of the sawdust “chunk”.

• Gullet Area [square inches] ÷ Sawdust Expansion Factor
• Sawdust expansion factor: 1.8 to 2.0 for slow growing species (ie. northern spruce/pine), 2.5 for fast growing species (ie. southern yellow pine).

Gullet Fill %

Gullet fill % is determined by the depth of cut and the tooth bite.  This calculation is used to determine available gullet fill capacity.

• Depth of Cut [inches] × Tooth Bite [inches] x Sawdust Expansion Factor ÷ Gullet Area [square inches] × 100
•  Sawdust expansion factor: 1.8 to 2.0 for slow growing species (ie. northern spruce/pine), 2.5 for fast growing species (ie. southern yellow pine).