Izzy Swan shared the woodworking tip featured in this video.
Izzy demonstrates a simple, adaptable jig that produces precise elliptical arcs and full ellipses by constraining pivot points to perpendicular planes and guiding a marking or cutting head around a plate.
The concept is versatile enough to mark arches, cut elliptical tabletops, and generate decorative patterns with a router or a simple marker for layout work.
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How the Elliptical Jig Works
The jig relies on two pivot points that each travel along planes set at 90 degrees to each other, which forces a marking point to trace an ellipse.
Expanding the idea to a four-block, two-rail arrangement lets the point travel a complete elliptical path for cutting or profiling.
Design and Layout
The core components are a base plate, guide rails, and sliding blocks with angled faces that capture those rails securely.
The angle simply provides a dovetail-like capture so the slides move smoothly without lateral play, which is essential for clean ellipses.
Preparation and Fit
Accurate, snug fits are the most important part of the build—slides should move freely but not wiggle in their slots, and mock-up rails can be used to check alignment before final fastening.
Small tacks or brads are useful for temporary assembly while checking fit, followed by countersunk fasteners to lock the parts in place.
Building the Moving Parts
Make the sliding pieces compact so they won’t interfere when the grooves cross during motion, and use recessed bolt heads or similar fasteners so nothing protrudes from the slide faces.
Checking travel and adjusting bolt tightness will prevent binding and keep the motion consistent across the whole rotation.
Plate and Marking Strategy
A rigid, flat plate with a centered layout line and a series of hole positions down its length lets the user vary the ellipse by changing which holes the pivots occupy.
For demonstration, a marker can be used in place of a router to visualize the path, and a router can then follow the same path in multiple light passes when cutting actual material.
Applications and Variations
With this jig, builders can mark elliptical arches, cut tabletops, and produce decorative inlays or patterns by simply altering hole positions and plate size.
The system scales: larger plates and longer rails produce bigger ellipses, while closer pivot positions yield narrower, more elongated forms.
Practical Tips and Safety
Keep sliding components narrow, test motion before committing to cuts, and use dust protection when cutting engineered materials or flooring-type plates.
Trial runs with a marker or a shallow router pass help verify geometry and reduce the chance of mistakes when removing real material.
Overall Takeaways
Izzy’s elliptical jig is an elegant, low-tech solution for a shape that can otherwise be difficult to lay out and cut accurately.
The approach is adaptable, easy to scale, and useful for both layout and full cutting operations, making it a worthwhile addition to a woodworker’s toolbox.
Please support Izzy by visiting his website: https://www.izzyswan.com/.