Five-Cut Method Calculator
Precisely calculate the error in your table saw crosscut sled.
A perfectly square crosscut sled is essential for accurate woodworking. The five-cut method is a highly precise technique to measure and quantify the error in your sled's fence, allowing you to adjust it to near-perfect 90 degrees. This calculator takes the measurements from your five-cut test piece and does the math for you.
The process involves making five cuts on a square panel, which amplifies any error in the fence. By measuring the final offcut, you can determine how much your fence is out of square over a given distance. This calculator provides the error in inches per inch and inches per foot, giving you a tangible number to guide your adjustments.
Follow these steps to perform the five-cut method:
- Start with a Square-ish Panel: Take a stable, flat piece of plywood or MDF, roughly 12" x 12" or larger. The exact size doesn't matter, but all sides must be straight.
- Make Four Cuts: Label the edges 1, 2, 3, and 4. Make a cut on edge 1. Rotate the panel 90 degrees counter-clockwise and place the freshly cut edge against your sled's fence. Cut edge 2. Repeat this process for edges 3 and 4.
- Make the Fifth Cut: With the fourth cut edge against the fence, make a final, fifth cut to create a narrow offcut strip (about 1" wide). Do not move the main panel.
- Measure the Offcut: Carefully measure the width of the offcut strip at both ends. Measurement 'A' is the end that was part of edge 1. Measurement 'D' is the end that was part of edge 4. The other measurements (B, C) are not needed for the calculation but demonstrate the process.
- Enter Values: Input your A and D measurements into the calculator to find the error.
- Crosscut Sled: A jig that holds a workpiece and slides in the miter slots of a table saw to make precise cross-cuts, especially at 90 degrees.
- Fence: The reference surface on a sled or saw that the workpiece is held against to ensure a straight, square cut.
- Error Amplification: The principle behind the five-cut method. Each rotation and cut multiplies the initial error, making a very small inaccuracy large enough to be measured easily.
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Always double-check your measurements before cutting.
Account for the kerf (the width of the saw blade) in your calculations.
Consider wood movement (expansion and contraction) in your final dimensions.
Buy 10-15% extra material to account for mistakes and waste.