A bandsaw is a versatile woodworking tool that can make straight cuts and curves, including circles, with a thin, continuous band saw blade. To cut consistent and accurate circles on a bandsaw, the most effective approach is to make a dedicated jig to hold the workpiece. A good bandsaw circle cutting jig is simple to construct, easy to use, and can be reused to crank out multiple identical circles with precision. This saves a lot of time compared to attempting to draw circles freehand and cut them on the bandsaw.
With some basic workshop materials and a little planning, you can make a custom jig tailored to the particular circles you need to produce. The key steps involve building a sturdy cross-shaped base, installing an upright guide column, adding a sliding workpiece support, and finally marking and drilling pivot points for the desired circle diameters.
This guide will walk through the complete process of designing and constructing a bandsaw circle cutting jig from scratch using commonly available hardware and lumber. Follow along to gain the knowledge and skills to build your own.
Page Contents
Planning the Jig Design
Before starting construction, take time to think through your needs and sketch out plans for the jig. These steps will ensure the jig has the right specifications for your particular bandsaw and circle cutting tasks:
– Consider what saw features may impact the jig dimensions, such as table size, blade guides, and frame obstructions. Measure free spaces to determine size limits.
– Decide the range of finished circle diameters needed, both minimum and maximum. The jig should accommodate these sizes.
– Choose sturdy, thick materials to minimize unwanted flexing and vibration during cuts. Hardwoods like oak or maple are ideal choices.
– Determine the pivot point and how circles will be indexed. A central guide column with side pins works well for most jigs.
– Layout drawings don’t need to be fancy, but should show the overall shape and critical dimensions. This will be a reference during construction.
Careful planning and drawings will pay dividends by ensuring your jig functions smoothly right off the bat. Always tailor the design to your specific tool setup and project needs.
Assembling the Base
The foundation of the jig is a flat, stable cross-shape that sits securely on the bandsaw table while providing a square surface to attach the vertical guide and other components. Plywood or dimensional lumber approximately 3/4″ to 1″ thick makes a rugged and warp-resistant base. Consider using hardwood if available.
Cut four rectangular blocks of equal size for the arms of the cross shape. Length and width are dictated by your bandsaw table measurements. Join the blocks in a cross pattern using glue and screws, keeping the assembly square. Apply triangular corner braces on the underside for added strength and rigidity.
Sand the base smooth and finish as desired for appearance and surface protection. Apply wax or paste wax to the bottom to let the jig glide smoothly on the table during cuts. The completed cross base should sit flat and steady on the bandsaw table.
Installing the Guide Column
The guide column acts as the main vertical pivot axis for indexing circles on the jig. It should be installed in the center point of the cross base using a hole just large enough for a snug friction fit. Softwood lumber can be used for cost savings, but hardwood is ideal for smooth sliding action.
Cut the column 1-2″ square to the desired height above the base, leaving extra length to extend into the mounting hole. Locate the exact center of the cross base bottom and drill a hole stepped to fit – a Forstner bit works well. Insert the column and lock in place with a cross-pin or opposing screws.
To reduce slop and binding, sand the contacting faces of the base and column to ensure smooth sliding. A gloss urethane finish on the column also improves function. The guide column should rotate freely yet hold any position without slipping.
Adding the Sliding Support
With the pivot axis defined, the workpiece support cross slide can be installed. This will move in and out to set varying radiuses. Hardwood is again a good choice for durability and low friction on the column.
Cut a block as wide as the base thickness and drill a center hole sized to match the column diameter. Drill screw clearance holes to mount it as an outrigger on the base leg opposite the column. Slide the block onto the column – it should move freely but not have excessive slop.
Use a screw to lock the cross slide at the required radius measured from the center column. Add a stop block if desired to quickly return to frequently used positions. The sliding support can now index workpieces horizontally to cut circles.
Marking Circle Diameters
To complete the jig, drill indexing holes in the cross slide at the marked centers for each desired circle size. These will accept a pin or bolt that acts as the cutting pivot for workpieces. Carefully measure and mark the locations before drilling.
For example, to cut 4″, 5″, and 6″ diameter circles, start by finding those radii – 2″, 2.5″, and 3″. Mark these distances from the center column on the cross slide edges. Center punch the marks and drill through holes to accept smooth alignment pins.
Enlarge the holes slightly with a ratchet reamer for easier pin insertion. Label each size for quick reference. With the indexing holes completed, you can now pivot off any marked center point to cut corresponding size circles.
Using the Jig
With construction finished, the bandsaw circle cutting jig is ready for action. Just follow these simple steps to put it to use:
– Place the jig base on the bandsaw table and lock or clamp in position if needed.
– Loosen the cross slide and move it to the radius required for the first circle size. Tighten the locking screw.
– Insert an alignment pin in the proper indexing hole for the chosen diameter.
– Position your workpiece against the guide column and cross slide.
– Rotate the work around the pivot pin to cut the circular profile.
– Adjust to a new index point and cut additional circles.
The jig reduces freehand errors and guesswork to make cutting bandsaw circles safer, faster, and more accurate. Periodically wax sliding surfaces and keep sawdust cleaned off. Your jig will provide years of useful service.
Conclusion
A shop-built bandsaw circle cutting jig is easy to construct with common tools and lumber, yet offers big rewards for precision and productivity. By planning dimensions, assembling a sturdy base, adding a smooth column, installing a cross slide, and carefully indexing for different diameters, you can produce a jig tailored to your workspace and projects. The ability to repeatably cut quality circles with a bandsaw saves significant time compared to layout and scrolling methods. Your bandsaw gains added versatility to take on more circular cutting challenges. With a well-built jig, you’ll gain premium results and enjoyment from this essential woodworking machine.
Additional Tips
Here are some additional pointers to get the most from your bandsaw circle cutting jig:
Use stop blocks for frequent sizes
Adding stop blocks on the base next to the cross slide provides quick indexing for repetitive circle diameters. Just butt the slide against a block set for a particular size hole.
Consider thrust bearings
Attaching thrust or roller bearings to the cross slide where it contacts the column can further improve sliding action and reduce friction.
Make the base oversize
Allowing extra space around the column gives room to pivot larger workpieces. A 12″ x 12″ base is a good minimum size to start with.
Enable angle adjustments
The guide column can be tilted from vertical to cut circles at an equivalent bevel angle. Add an angle scale or adjustable wedge blocks.
Add dust collection
Attaching a flexible vacuum hose with zip ties or magnets helps keep the jig free of sawdust during heavy use.
Use index pins in both directions
The cross slide can have indexing holes on both inside and outside edges to support pivoting larger workpieces from either direction.
Switch materials as needed
While hardwoods work best for low friction, you can substitute plywood or plastic where appropriate to suit materials on hand.