Manufacturing Skills 2 – The Narrow Bandsaw

Origin: The bandsaw was patented in 1808 by William Newberry of England.
Development: The practical use of the bandsaw was hindered until 1846, when Anne Paulin Crepin invented a method to weld spring steel, improving blade durability.
Common Usage: Bandsaws are widely used in furniture making and effective for cutting wood; they can also cut materials like aluminum, brass, acrylic, and foam board (blades must change accordingly).

Definition: A bandsaw is a sawing machine that uses a continuous metal band with teeth on one side, primarily oriented vertically.
Safety Feature: The downward cutting motion minimizes the risk of kickback, enhancing user safety.
Unique Feature: Workpieces can be rotated around the blade, enabling precise curve cutting.
Efficiency: Produces a thin kerf, requiring minimal power and material is removed.

Pulley Wheels:
- Consist of two wheels (one above, one below).
- Thin rubber layer aids in gripping and maintains blade integrity.
Machine Table:
- Typically cast iron and can tilt up to 45 degrees for versatility.
Table Fence:
- Made of cast iron, pressed steel, or aluminum, allowing alignment on either side of the blade.
Frontal Guard:
- Encloses the blade section between the top pulley and workpiece, adjustable for safety.

Guard Requirements: Proper guarding of saw wheels and blade areas is mandated. The upper blade section must have protective guards close to the blade.
Braking Requirements: Modern bandsaws with CE marking must stop within 10 seconds of power loss. Older models may have a footbrake.

Thrust Wheel: Provides support at the back edge of the blade to prevent backward movement during cutting.
Saw Guides: Located on either side of the blade, supporting it without contact; a small gap ensures there is no friction.

Tensioning:
- Applies tension to the blade for structural integrity and to handle heat-induced changes.
- Top pulley wheel raises via a handwheel, and tension indicators help gauge blade readiness.
Tracking: Ensures that the blade runs true on the pulley wheels, critical for accurate cutting.

Selecting Blade Width: Choose blade width based on the smallest curve radius. Always opt for the widest possible blade that fits the intended cut.
Cutting Tips:
- Keep hands away from the blade, maintaining a safe distance.
- Use sufficient speed; let the saw do the cutting. Excess pressure can cause blade damage or injury.

Power Off: Always switch off and engage the brake after using the saw, especially if leaving it unattended.
Blade Tension Maintenance: Relax the tension if not in use for extended periods to maintain blade integrity, but remind users to adjust tension before next use.

Blade Back: The body of the blade aside from tooth portion.
Kerf: The material removed by the blade during the cut.
Tooth Pitch: Distance between tooth tips.
TPI: Teeth per inch measured from gullet to gullet.
Tooth Face: The side of the tooth that forms the chips.
Tooth Rake Angle: Angle of the tooth face relative to the cutting direction.

Width Variation: Use narrow blades for tight curves and wider blades for straight cuts.
Tooth Design: Different shapes and pitches are available depending on materials (plastics, metals, wood).

Formula: Length = 2 x distance between pulley centers + circumference of one wheel - 25mm

Example Calculation: 2400mm between pulley centers + 1884mm (circumference) = 4259mm blade required.

Recommended websites and literature for band saw operation and maintenance include The Wood Whisperer and CITB Wood Machining Training Manual. Work on practical joinery books focuses on bandsaw usage as well.