5.1: Band Saw
- Page ID
- 67184
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5.1 Band Saw
The band saw is one of the most useful machines for shaping wood.
Unlike a table saw, which is primarily used for straight cuts, the band saw can follow curves. It is also used for rough ripping and resawing, which means cutting a board through its thickness to make thinner pieces.
The band saw is a rough-cutting and shaping machine. It is not intended to leave a finished surface.
Learning Outcomes
After completing this section, you should be able to:
- Explain the primary uses of the band saw.
- Identify the major parts of the machine.
- Explain why relief cuts are useful.
- Describe the basic WMT safety requirements for band-saw use.
- Explain the difference between cutting a curve and resawing.
How the Band Saw Works
A band saw uses a continuous loop of narrow steel blade running over wheels above and below the table.
At the cutting area, the blade moves downward through the table.
Because the blade is narrow, it can follow curves that would be impossible to cut safely on many other woodworking machines.
Major Parts
Important parts include:
Blade — The continuous cutting band.
Table — Supports the workpiece.
Upper Blade Guide — Supports the blade above the work.
Blade Guard — Covers the exposed portion of the blade above the workpiece.
Guide Adjustment — Raises or lowers the upper guide and guard.
Throat Plate — Surrounds the blade where it passes through the table.
Power Switch — Starts and stops the machine.
Brake — Helps bring the blade to a controlled stop after the power is turned off.
Figure: Band Saw
Adjust the Guide Before Cutting
Before turning on the machine, lower the upper guide and guard to approximately:
1/4 inch above the workpiece
The guide should be close enough to support the blade while still allowing the work to move freely.
Never adjust the blade guide while the saw is running.
Cutting Curves
Plan curved cuts before turning on the machine.
The tighter the curve, the more difficult it is for the blade to follow.
Do not force or twist the workpiece against the blade.
Instead:
- approach the layout line gradually;
- use smooth forward movement; and
- make relief cuts when necessary.
Relief Cuts
A relief cut is a cut from the waste edge toward the finished layout line.
Relief cuts divide a large waste area into smaller sections.
As the curved cut progresses, the small waste pieces fall away instead of trapping the blade or forcing you to make an excessively tight turn.
Relief cuts are especially useful for:
- long curves;
- tight curves; and
- shapes with changing radii.
Leave the Line
As with other rough-shaping operations, do not try to make the band saw produce the final finished surface.
Cut close to the layout line while leaving a small amount of material for later shaping and sanding.
The band saw establishes the form.
Files, rasps, spokeshaves, and abrasives refine it.
Backing Out of a Cut
Do not pull a workpiece backward out of a cut while the blade is running.
Backing out can pull the blade off the wheels.
If the stock becomes trapped or you need to back out of a long cut:
- Turn off the power.
- Wait until the blade stops completely.
- Remove the work carefully.
- Ask your instructor for assistance if the piece does not release easily.
Margin of Safety
Maintain at least a:
4-inch margin of safety
between your fingers or other body parts and the blade.
Use a pushstick or other guide when a cut would place your hands too close to the blade.
Resawing
Resawing means cutting through the thickness of a board to produce thinner pieces.
For example, a thick board might be resawn into two thinner boards.
Resawing requires:
- a straight edge against the table;
- a flat face against the resaw fence; and
- a pushstick.
Resawing is an instructor-approved setup in the WMT lab.
Irregular and Round Stock
Round or irregularly shaped material can rotate unexpectedly when it contacts the blade.
Cylindrical or irregular work must be supported with an appropriate jig, such as a V-block, and treated as a special setup.
Never attempt to hold a round object directly on the table and cut it freehand.
Important WMT Limits
For normal use:
- Adjust the upper guide to about 1/4 inch above the stock before starting.
- Maintain a 4-inch margin of safety.
- Allow the blade to reach full speed before cutting.
- Do not adjust the machine while it is running.
- Do not back work out while the blade is moving.
- Keep guards and doors in place.
- Use a pushstick when required.
- Resawing and unusual setups require instructor approval.
- Do not stand directly to the right side of the band saw while it is running.
- If you hear an unusual clicking sound, shut the machine off and notify your instructor.
Check Yourself
- Why is the band saw considered a rough-cutting machine?
- What is the purpose of a relief cut?
- How high should the upper guide normally be above the work?
- What is the required margin of safety?
- Why should you not back a workpiece out while the blade is running?
- What is resawing?