A wood router jig is a shop-made or store-bought guide that holds a handheld router on a fixed line, curve, or template so every cut comes out the same.
Whether you’re cutting a dado, recessing a hinge, or routing a speaker baffle, the jig carries the accuracy.
How Does a Router Jig Control the Cut?
Every jig removes the router’s freehand freedom and locks the tool to a reference surface: a straightedge, fence, template, pivot point, or guide rail — sometimes a guide bushing or bit bearing.
A straightedge or fence clamps to the workpiece and the router base rides against it. A template goes further — the router follows it with a guide bushing or pattern bit, which sets the exact offset between guide and cut. A circle jig trades the fence for a pivot: the router mounts to one end of a rigid arm, a pin anchors the other at the center, and the bit sweeps a fixed radius. Change the pivot-to-bit distance and you change the radius.
What Are the Most Common Router Jig Types?
Most jobs fall into a handful of jig families, each solving a specific accuracy problem.
| Jig Type | What It Cuts | How It Guides |
|---|---|---|
| Straightedge or edge jig | Straight cuts, panel trimming | Clamped fence parallel to the cut line |
| T-square or dado jig | Dados and rabbets perpendicular to an edge | Perpendicular fence indexed to the bit |
| Circle or trammel jig | Circles and arcs | Pivot pin at center, fixed radius arm |
| Ellipse jig | Ovals and elliptical openings | Adjustable pivots set to two axes |
| Template jig | Hinge mortises, hardware recesses, inlays | Guide bushing or bearing following the pattern |
| Mortising jig | Mortises for joinery | Constrained slide or bracket |
| Dovetail or box-joint jig | Repeatable joinery pins and tails | Indexed comb or angled fence |
Commercial versions exist for worktop miters, hinge recesses, and lock pockets, adding depth stops, corner guides, and dedicated clamps. Shop-made jigs handle the same tasks for the price of scrap plywood. If you’d rather buy than build, this roundup of tested wood router jig options covers the standouts.
How Do You Set Up and Use a Dado Jig?
A T-square or dado jig produces clean, square-bottomed channels, and the method hinges on one measurement: the distance from the bit’s cutting center to the edge of the router base. Get it wrong and the cut lands off by that exact amount. Straight from Popular Woodworking’s shop-jig walkthrough:
- Mark the dado location with a marking gauge or square.
- Measure the offset from the bit’s cutting center to the relevant router base edge.
- Position the jig so the bit aligns with your mark once that offset is accounted for.
- Clamp the jig firmly, keeping clamps clear of the base and bit path.
- Feed the router against the bit’s rotation — right to left for the setup that guide describes.
You’ll see a straight channel with square walls and a clean bottom — and the router will fight you if you feed the wrong way, the most common reason a dado jig chatters or climbs.
Circle jigs follow a similar shallow-pass rhythm. Let the router reach full speed before the bit touches wood, then work in progressively deeper passes. It’s set right when the pin holds, the arm stays rigid, and the circle closes on itself without a step.
What Goes Wrong With Router Jigs?
Nearly every bad jig cut traces back to a mismeasured offset or a straightedge clamped on the wrong side. Clamp the guide so cutting forces push the router into the fence, not away from it, or the base will wander on the first pass. Three habits keep jigs honest:
- Deep bites overload the bit and bow the base.
- Keep clamps outside the router’s travel path. A nicked clamp is a bad afternoon.
- Recheck the offset before every new setup. Router bases aren’t all the same diameter, so the number rarely transfers.
Keep the jig clamped, the passes shallow, and the feed direction consistent, and the cut lands where you planned.
Common Questions
Do I need to buy a router jig or can I build one?
Shop-made jigs cover most needs — a straightedge and clamped fence handle most straight cuts, and a scrap-plywood circle jig takes an evening. Buy commercial for repeatable depth stops, dedicated clamps, or precision for joinery and hinge work.
What is a guide bushing used for on a router jig?
A guide bushing rides against a template and offsets the bit from the template edge by a fixed amount, letting the router follow a pattern without touching it. Bushing and bit size must match the template geometry.
Can a router jig cut a circle without a pivot pin?
Not a true circle. Every trammel-style jig relies on a fixed pivot — a pin, nail, or screw at the center mark — with the router at a fixed radius. Without that anchor, the router has nothing to rotate around.
Sources
- Popular Woodworking. “4 Simple Shop-Made Router Jigs.” Source for dado and circle jig construction steps, pass depths, and example dimensions.
- Wood Magazine. “Router Jigs.” Source for jig types and their shop applications.
- Rockler. “Rockler Router Jigs.” Source for commercial jig categories including hinge, worktop, and lock jigs.