Wood Kerf Bending Cut Spacing & Radius Calculator
Calculate exact center-to-center saw kerf spacing, number of relief cuts, blade depth, and arc allowance to bend plywood, MDF, or solid wood around any radius curve.
Standard full-kerf table saw blade is 3.2mm (1/8"). Thin-kerf track saw blades are 2.2mm (3/32").
Center-to-Center Cut Spacing
33.0 mm
Mark along flat workpiece
Total Number of Kerf Cuts
8 Cuts
Evenly spaced across arc
Saw Blade Cut Depth
15.5 mm
Total Flat Arc Length
263.9 mm
Live Kerf Relief Cut Spacing Diagram
90° Kerf Bending Quick Reference Chart (18mm / 3/4" Plywood, 3.2mm Blade)
Pre-calculated kerf cut counts and center-to-center spacing for 18mm (3/4") plywood leaving a 2.5mm uncut outer veneer skin.
| Inside Bend Radius | Outer Arc Length | Required Kerf Cuts | Center-to-Center Spacing |
|---|---|---|---|
| 100 mm (4") | 185.4 mm | 8 Cuts | 23.2 mm (0.91") |
| 150 mm (6") | 263.9 mm | 8 Cuts | 33.0 mm (1.30") |
| 200 mm (8") | 342.4 mm | 8 Cuts | 42.8 mm (1.69") |
| 300 mm (12") | 499.5 mm | 8 Cuts | 62.4 mm (2.46") |
How the Kerf Bending Geometry Formula Works
When bending a board of thickness T around an inside radius R, the outer face must travel a longer arc than the inside kerfed face. The total amount of wood that must be removed by your saw blade equals the difference between the outer arc length and the inner arc length at the bottom of the kerf cuts:
Cut Spacing = [ Angle_Radians × (Inner_Radius + Board_Thickness) ] ÷ N
Frequently Asked Questions (Kerf Bending Calculator)
How thick should the remaining wood skin be when kerf bending plywood?
Leave 2.0mm to 3.0mm (roughly 3/32 inch to 1/8 inch) of uncut face veneer when kerf bending Baltic birch or hardwood plywood. Cutting deeper risks cracking the outer face grain, while leaving more than 3.5mm resists bending.
How do you calculate the distance between saw kerf cuts for a curve?
Divide the outer arc length of your bend by the required number of cuts, where the number of cuts equals the difference between the outer arc length and inner arc length divided by your saw blade kerf thickness.
Should kerf cuts be filled with glue when bending wood?
Yes. Spreading thickened epoxy, polyurethane adhesive, or PVA glue mixed with fine sawdust into the open kerfs before clamping locks the closed kerf walls together and prevents springback once removed from the form.
Why do faceted flat spots show through my kerf-bent curve?
Flat telegraphing happens when kerf cuts are spaced too far apart or cut too close to the face veneer. Keep center-to-center spacing under 25mm (1 inch) for tight radii and steam or dampen the outer face slightly before bending.
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