How to read the cutting pattern
The picture is the small end of the log. Grey is slab and edgings, light wood is the cant, colored rectangles are boards and timbers — each size keeps its color. The pattern saws around the log, the way most band-sawmill operators do:
- Open face A (top): slab off, then the boards above the cant.
- Turn the log 180° and saw face C the same way.
- Turn 90° and saw face B, then turn 180° for face D.
- Saw the remaining cant into boards or leave it as a timber.
Each tile shows the blade height above the bed for that cut — in sixteenths of an inch or whole millimetres. Boards from faces A and C have wane on both edges and must be edged; boards from B and D usually come off square-edged.
Max yield or fewer cuts
Max yield fits as much lumber into the log as the sizes allow, using thinner boards near the bark. Fewer cuts trades a few percent of yield for fewer cuts and less edging — usually a big timber in the middle and wide boards around it. On a busy day the faster pattern often makes more money.
What the calculator assumes
- The log is straight and round; the pattern is figured on the small-end diameter, so every board runs the full length of the log. Extra wood from taper near the butt end is not counted.
- Sizes are rough (full) sizes, the way a sawmill cuts them. Add your own allowance for shrinkage and planing to the sizes if you need finished dimensions.
- Yield is lumber volume divided by the volume of the small-end cylinder. Overrun compares the lumber with the Doyle and International ¼ scale of the same log.
Tips from the mill
- The first and the third cuts are the riskiest: the log lies on its round side. Clamp it well and check that it can't roll before the blade goes in.
- On a tapered log, raise the small end with the toe boards so the opening cut runs parallel to the bark — you get longer clear boards from the outside.
- Measure the small end inside the bark. An extra inch of bark in the diameter breaks the whole pattern.
- Wear ear muffs on the carriage. A band mill under load runs around 100 dB at the operator's spot and a circular head saw is louder — what 100 dB means for your hearing and how few minutes a day it takes to do damage.
Counting the lumber afterwards? The board foot calculator totals a stack by size and price.