What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
A router trammel fixes the router’s path around a center pivot, letting you cut circles, arcs, discs, and rings. Accuracy depends on measuring from the pivot center to the bit’s cutting edge that will form the boundary, anchoring the pivot securely, and checking that the router can travel safely through the entire cut.
Choose the right trammel for the job
You can build a trammel from plywood or use a commercial jig. Either way, check that it fits your router and base, reaches the circle size you need, and supports the router throughout its travel. A pivot that pierces the work creates a center mark; some designs use an attached pivot base instead.
Shop-built plywood trammel
WOOD Magazine’s 2017 design uses 3/4-inch plywood, a carriage bolt, a wing nut, and a straight bit. Its beam is about 12 inches longer than the radius of the largest circle intended, with a 4-inch-wide narrow section and a 3/8-inch slot through that section. A 1-inch-wide, 3/8-inch-deep groove on the underside lets the carriage-bolt head slide. The pivot base is also 3/4-inch plywood, with a 3/8-inch hole 1 inch from its front edge. Shape one end of the beam to match the router base; the bolt slides in the slot to set the radius, and the wing nut locks it. Follow the article’s original drawing for the design’s orientation rather than treating these dimensions as a universal pattern. See WOOD Magazine’s trammel design.
Commercial jigs
Published ranges and fit details vary by model. Treat these as manufacturer or retailer specifications, and verify the exact router base and current product details before buying.
#1 Best Overall
- LARGE CUTTING RANGE: Small circle router guide jig cuts circles from 1. 5" To 12" In diameter; Large circle Jig cuts circles from 10" To 52" In diameter
- EASY TO USE: Both the small and large circle jigs have built in metric and imperial scales, with an easy readout window for setting the diameter of both your inside and outside cuts
- UNIVERSAL COMPATIBILITY: Both the small and large circle jigs quickly and easily attach to the included turn-n-lock circle guide head
- WOODWORKING TOOLS: Bonus 13" Offset base provides added stability when finishing the edges on your work piece using your router, oversized handle knob is easy to grip providing superior control of your router
- PREMIUM MILESCRAFT TOOLS: Equipped with the patented turn-n-lock technology allowing for fast tool-free guide Bushing and router attachment exchanges
| Jig | Published diameter range | Compatibility or pivot details |
|---|---|---|
| Rockler Circle Cutting Jig | 10–52 inches | Retailer lists popular Porter-Cable, Makita, Hitachi, DeWalt, and Bosch routers; custom mounting holes can be drilled for other routers. Not predrilled for the Bosch Plunge Base. |
| Rockler Trim Router Circle Jig | 6–36 inches | Retailer lists predrilled fit for Bosch 1617 series fixed base, Bosch Colt PR20EVSPK, DeWalt DWP611PK, and Porter-Cable 450PK. Includes a sharp pivot for soft wood and a blunt pin where a center hole is acceptable. |
| Trend CRB circle/ellipse arrangement | 19–224 mm radius | Trend says an extension kit can enable larger circles; this is a specification for its system, not for trammels generally. |
Sources: Rockler Circle Cutting Jig, Rockler Trim Router Circle Jig, and Trend circle-cutting technique. Product dimensions and compatibility can change; check the current manufacturer or retailer listing for your particular model.
Set the pivot-to-cutter distance
The radius is the distance from the center of the pivot to the cutting edge that defines the finished boundary—not simply to the router base or the bit’s center. WOOD’s large-circle guide specifies measuring from the inside of the straight bit’s cutting edge to the center of the trammel pivot pin for its setup. For your cut, identify the edge that will actually finish the boundary and set the distance accordingly. Diameter is twice the radius.
Rank #2
- 10"–58" Large Circle Cutting Range: Built for larger woodworking projects, this router circle jig cuts precise circles and arcs from 10" to 58" in diameter. The oversized base and extension rod provide the extra reach needed for large tabletops, signs, furniture panels, speaker projects, and other oversized circular cuts.
- Broad Router Compatibility with Oversized Base: The large multi-hole base is designed to fit a wide range of handheld and compact routers across popular brands and models. Multiple mounting-hole patterns accommodate different router bases and screw spacing, giving you greater flexibility when matching the jig to your router.
- Circle Cutting, Grooving & Straight-Line Routing: More than a circle cutting jig, this versatile router guide can also be paired with the positioner for grooving and straight-line routing. One setup handles circular, curved, and linear routing tasks for furniture making, cabinetry, and DIY woodworking projects.
- One-Piece Die-Cast Aluminum Construction: The rigid aluminum base helps minimize flex and unwanted movement while routing. Combined with the extension rod and stable mounting system, it helps keep the router on the intended cutting path for cleaner edges and more consistent results.
- Quick Setup & Compatibility Check: Align the multi-hole base with your router's existing mounting holes, tighten the screws evenly, adjust the extension rod to your desired cutting diameter, and start routing. Because router base designs vary by model, check your router base size and mounting-hole spacing before ordering.
- Outside circle or disc: Set the pivot-to-cutter distance to the desired outside radius, using the outside cutting edge that will form the finished perimeter.
- Inside opening: Set the distance to the opening boundary made by the relevant cutting edge. Confirm the finished opening size with the router off before cutting.
- Ring: Set and cut the outside and inside boundaries separately. The ring’s width is the difference between the two radii; account for which bit edge forms each boundary.
For an example, a 20-inch-diameter outside circle has a 10-inch radius, so the relevant cutter edge must follow a 10-inch radius from the pivot center. The bit’s cutting width matters when laying out an opening or both edges of a ring; do not assume a pivot setting to the bit center will produce the intended finished boundary.
Anchor and check the setup
WOOD’s large-circle method places the pivot pin in a hole in the workpiece bottom, sized for the pin and at least 1/4 inch deep without going through the work. It also describes attaching a scrap pivot block to the underside. A through-hole is not the only arrangement: the pivot and jig design determine whether the workpiece receives a visible center mark. Secure the work so it cannot shift, and keep the router base supported throughout its path.
Quick wins for a faster PC:
Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Clear out junk files and repair common Windows errorsFree Scan →Rank #3
- Compatible with 10+ Compact Router Models: Direct bolt-on fit for Makita RT0701C, Makita 3709, DeWalt DWP611, Bosch PR20EVS Colt, Milwaukee 18V Router, RYOBI PCL424, RIDGID R2401, WORKPRO 6.5 Amp, AVID POWER 6.5 Amp 1.25HP, and THINKWORK 6.5 Amp 1.2HP. No adapter or drilling required—the base plate uses your router's existing mounting holes for a stable, aligned setup.
- Cuts Circles from 5.5" to 30": The adjustable radius guide creates accurate circles and arcs for speaker boxes, tabletops, cabinet cutouts, signs, and trim work. Pair it with a compatible positioner for grooving and straight-line routing, expanding the jig beyond circle cutting.
- Quick Setup & Easy Portability: Designed for quick installation and removal on compatible compact trim routers. Align the base plate, tighten the screws, set your cutting radius, and you're ready to route. Its lightweight, detachable design makes it easy to store or carry from the workshop to the job site.
- One-Piece Die-Cast Aluminum Construction: The rigid aluminum body helps minimize flex while routing, keeping the router on the intended radius for cleaner edges and more consistent circle diameters.
- Check Compatibility Before Ordering: If your router is listed above, it is designed for direct mounting. For other models, confirm that the diagonal mounting-hole spacing on your router base is between 2.36" and 3.94" (6–10 cm) before ordering.
- Lay out the center and radius. Mark the intended center, then set the pivot-to-cutter distance for the boundary you are cutting.
- Lock the adjustment. Tighten the trammel’s knobs, bolt, or other lock so the radius cannot slide during routing.
- Make an unpowered sweep check. With the router unplugged or disabled as its manual directs, move the arm through the full intended path. Confirm smooth travel, the intended circle, adequate base support, and that the router will not run off the work. Rockler’s 55819 compact circle/ellipse jig instructions specifically call for checking the full path with the router off.
- Confirm the cut plan. Check the bit, workholding, stock support, and planned depth against the router and jig manuals. Do not assume a trammel makes an otherwise incompatible router or cutter suitable.
Route the circle, arc, disc, or ring
Cutting a large disc or circle
For large work, first rough-cut the blank close to the finished diameter, then use the trammel-guided router to true the edge. WOOD recommends rough-cutting to within 1/8 inch of the finished diameter before routing. Its 2025 guide says the illustrated homemade jig can cut circles up to 72 inches in diameter; that figure applies to that design, not to every homemade jig. Read WOOD’s large-circle method.
Cutting an opening or ring
For a ring, route the outside diameter first, as WOOD’s 2017 design article advises, then reset the jig for the opening. Make separate radius settings for the two boundaries and confirm both before routing. Choose the order and support arrangement so the work remains stable as material is removed; the router base must stay supported during each pass.
Rank #4
- ⭐ WOOD MAGAZINE'S ONLY GRADE A CIRCLE JIG – Cut 268 perfectly sized circles from 1½" to 18 3⁄16" in precise 1/16" increments. When WOOD Magazine tested dozens of circle routing systems, only Jasper earned Grade A (competitors received B+ or lower). Ideal for speaker cutouts, rings, inlays, templates, and precision detail work. Part of a 25-year engineer-founded legacy with 100,000+ units sold.
- 💪 ONE PRECISION SYSTEM — TWO PERFORMANCE LEVELS – Both Standard and PRO use Jasper's legendary CNC-machined pivot holes and precision calibration disc for repeatable accuracy. Choose Standard (hardened acrylic) for everyday projects, or PRO (industrial-grade polycarbonate) for maximum durability and lifetime peace of mind. Same precision geometry. Different materials. Different warranties.
- 🔧 ENGINEER-FOUNDED PRECISION – Created by aerospace-era engineer Les Jasper who demanded obsessive accuracy. Not mass-market compromise—this is engineer-level precision proven through 25 years and 100,000+ units sold across the complete Jasper system. The Jasper family of circle guides has earned 4.6★ across 2,393 verified reviews. When craftspeople comparison-shop for circle jigs, they choose Jasper. Now you know why.
- Bullet 4: 📊 STANDARD VS PRO — MATERIAL MAKES THE DIFFERENCE – Standard: Hardened acrylic construction, limited lifetime warranty against manufacturing defects with registration, perfect for everyday shop and DIY use. PRO: Industrial-grade polycarbonate with superior strength and wear resistance, full lifetime replacement guarantee with registration, built for professionals and high-volume users. Both deliver identical Jasper precision.
- ⚠️ ROUTER COMPATIBILITY CHECK REQUIRED – Fits most compact, trim, and cordless routers including Bosch Colt, DeWalt DCW600/DWP611, Makita XTR01, Milwaukee M18 FUEL, Porter Cable, Ridgid, Ryobi, and more. NOT for full-size plunge routers (use Model 200/240 instead). CRITICAL: Check our detailed compatibility chart before ordering to ensure proper fit and prevent returns. Compatible brands listed for reference only.
Cutting an arc or curved trim
A trammel can guide an arc as well as a full circle. For curved trim, Fine Homebuilding describes finding the pivot center by drawing arcs from the workpiece corners and using their intersection, then routing the inside and outside radii before rough separation and edge cleanup. That layout approach is useful when a curve must relate to the corners of a trim piece; it is not necessary for an ordinary circle. See Fine Homebuilding’s curved-trim layout.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Use multiple passes for deep cuts
Rockler’s 55819 compact circle/ellipse jig instructions, revision 06/22, state: “Do NOT attempt to make the full depth of cut in one pass.” They direct users to increase depth over several passes. The instructions are product-specific and do not establish a universal pass depth; follow the current manuals for your router, cutter, and jig. Read the Rockler jig instructions.
Recommended Free Tools
Quick Recap
Best Value
- 【Universal Compatible Router Jig】This router circle cutting jig is specifically designed for compact routers and is compatible with Dewalt and Makita routers and edging tools, helping woodworking enthusiasts with edge routing and circular groove cutting
- 【Adjustable Circular and Curved Cutting】With an adjustable radius ranging from 3.15 to 15 inches, it enables precise cutting of circles (up to 30 inches in diameter), curves, and grooves. This versatile router circle jig can also perform straight cuts. Featuring dual imperial and metric scales with 1/4-inch precision, it ensures accurate and repeatable results for every project
- 【30-Second Quick Setup】Comprising three modular components, it can be easily assembled or disassembled without complex tools. Adaptable to a wide range of woodworking tasks, this router guide is suitable for both workshop and on-site construction
- 【High-Quality Material】Made from upgraded, thickened aluminum alloy with CNC-machined components, its smooth, flat surface provides stable support for the router, effectively reducing vibration. This router guides for woodworking offers exceptional durability and stability. Its 4-in-1 integrated design prevents warping, bending, or loss of precision—unlike wooden DIY jigs—and is built for years of reliable woodworking
- 【Wide Material Compatibility】Optimized for medium-density fiberboard (MDF), particleboard, solid wood, and engineered wood. Whether you’re making tabletops, picture frames, signs, or custom furniture, this router jigs delivers clean, professional-grade cuts for all your woodworking projects
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
