This calculator uses a standard rule of thumb for clamp placement. Here's the logic:

1. Place End Clamps: The first two clamps are always placed near the ends of the panel. The rule is typically 2 to 4 inches from the edge. This calculator uses a proportional distance to accommodate various panel sizes.
2. Determine Remaining Space: The calculator subtracts the space taken up by the end clamps from the total panel length.
3. Space Interior Clamps: The remaining length is divided into gaps of approximately 8 to 12 inches. The calculator aims for a 10-inch spacing and calculates how many clamps are needed to achieve this.
4. Calculate Final Layout: Based on the number of clamps, it calculates the final, even spacing between them and presents the layout to you. This ensures consistent pressure across the entire panel.

• Panel Glue-Up: The process of joining several narrower boards edge-to-edge to create a single, wider panel.
• Bowing/Cupping: The tendency of a panel to warp or curve under uneven clamping pressure.
• Cauls: Stiff boards or battens, often with a slight curve, placed across the panel (perpendicular to the glue lines) to help distribute pressure evenly and keep the panel flat.
• Even Pressure Distribution: The primary goal of clamping; ensuring the force is applied consistently along the entire length of the glue joint.

"The #1 rule for panel glue-ups is to alternate your clamps. Place one clamp on top of the panel, the next one underneath, and so on. This creates opposing forces that cancel out any tendency for the panel to bow under pressure. The calculator shows this in the diagram with light and dark clamps. It's a simple step that makes a huge difference." - Veteran Woodworker

"Don't just clamp along the glue lines. For wide panels, you also need to use cauls across the top and bottom, clamped lightly. This prevents the boards from buckling upwards and ensures the joints are perfectly flush. Your glue-up should be flat first, then clamped for pressure second."

Example 1: A 36-inch Bookshelf
The calculator will suggest 4 clamps. It will place one clamp about 3 inches from each end. The remaining 30 inches are then spanned by the other two clamps, resulting in a spacing of about 10 inches between all clamps.

Example 2: A 6-foot (72-inch) Tabletop
For a long panel like this, the calculator will recommend around 8 clamps. Two will be placed near the ends, and the remaining six will be spaced evenly across the interior, ensuring no part of the glue line is more than 5-6 inches from a clamp.

• Clamping Only from One Side: This is a guaranteed way to make your panel bow. Always alternate clamps on the top and bottom.
• Placing Clamps Too Far Apart: Spacing clamps more than 12-15 inches apart can create weak spots in the glue line between the clamps.
• Focusing Only on the Center: Many people place clamps in the middle and forget the ends. The ends of boards are most prone to separating, so they need dedicated clamps.
• Ignoring the Surface Underneath: Clamping a panel on an uneven surface will build a permanent warp into your project. Always use a known flat reference surface, like a sturdy workbench or assembly table.

• Edge-Gluing Panels: The primary use case, for making tabletops, cabinet sides, cutting boards, etc.
• Laminating Boards: When face-gluing boards to create thicker stock, even spacing is still important to prevent bubbles and ensure a solid bond.
• Long Miter Joints: Ensuring long mitered case corners come together tightly and evenly.