A plunge router and a stable, shop-built jig can cut matching mortises for a loose-tenon joint without a dedicated joiner. The method is adaptable, but it depends on accurate layout, secure clamping, and test cuts. Here’s how to make the joint, size its parts, and decide whether a router jig, drill-powered mortising jig, or dedicated joiner suits your work.
How a loose-tenon joint works
A loose-tenon joint uses a separate piece of wood to connect two workpieces. Each piece receives a mortise, and the tenon fits into both. Unlike a traditional mortise-and-tenon joint, the tenon is not cut as part of either workpiece. The method is also called floating-tenon joinery. WOOD Magazine and Woodcraft describe cutting the matching mortises with the same machine or jig so the separate tenon bridges the joint.
Cut matching mortises with a plunge router
A router jig supports and guides the plunge router while the workpiece is held in position. WOOD Magazine’s method uses a spiral upcut bit, layout marks, stopblocks, and test cuts in scrap that matches the project stock. The bit cuts as it plunges and carries chips up and out of the mortise. Make several progressively deeper passes rather than trying to reach full depth at once.
- Lay out both parts from a common reference. Mark the mating workpieces so the mortises will align when the joint is assembled. Keep track of which faces and edges are intended to remain flush.
- Secure the workpiece and set the stops. Clamp the part firmly in the jig. Set the router bit depth and the stops that control mortise length before cutting.
- Test the setup in matching scrap. Use scrap with the same thickness and, where practical, the same species as the project. Check the mortise’s width, length, depth, and position against the tenon and the mating part.
- Rout in staged passes. Plunge gradually, increasing the depth in successive passes until you reach the target. Keep the router guided by the jig and the workpiece clamped throughout.
- Dry-fit before applying glue. Insert the tenon and bring the parts together. Correct any fit or alignment problem before glue-up; the faces and edges should meet as intended.
- Glue and assemble. Brush glue into the mortises, insert the tenon, and bring the parts together while checking that their faces and edges stay flush. Chamfering the tenon ends can ease insertion; making the tenon slightly narrower than the mortise can leave some room for adjustment during assembly.
Choose mortise and tenon dimensions
Woodcraft offers these rules of thumb for loose-tenon sizing. They are guidelines, not universal design requirements; confirm the fit with test cuts using the actual stock, bit, and jig.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errors#1 Best Overall
- 14 AMP PLUNGE ROUTER - Powerful 14 Amp, 2.5 HP motor includes both fixed and plunge bases for a variety of work.
- SPEED CONTROL LCD DISPLAY - Lets you select the bit type and material for suggested speed settings based on the task at hand.
- ELECTRONIC FEEDBACK - Ensures motor maintains RPM while the material is being routed.
- SOFT START - Provides a safe and controlled start to routing.
- LIVE TOOL INDICATOR - Stay safe and alert with an indicator that lights up when plunge router is connected to power.
| Feature | Woodcraft guideline | Practical check |
|---|---|---|
| Mortise width | Use the bit size; aim for about one-third the thickness of the thinnest mating piece. | Check the resulting wall thickness and tenon fit in scrap. |
| Mortise length | About two-thirds the width of the narrower mating piece. | Confirm that the mortise leaves adequate material around it for the joint and workpiece. |
| Mortise depth | As deep as practical for the bit, with at least 1/16 inch extra beyond half the tenon length. | Verify that the tenon can seat without bottoming out before the joint closes. |
These proportions come from Woodcraft’s loose-tenon guidance, published April 10, 2009, with the page reporting an update on May 6, 2026. Treat them as starting points rather than a substitute for a test fit.
Choose the right mortising approach
The main trade-off is between flexible, shop-built setup and the convenience of a purpose-built tool. Compare the equipment you already own, the time needed to set up, the mortise sizes and shapes required, and the compatible tenons available for the system.
Rank #2
- 2-1/4 HP (maximum motor HP), 12.0 amp electronic variable speed motor of DEWALT router provides the power to rout smoothly through the toughest hardwoods
- DEWALT plunge router features electronic variable speed with full feedback control for constant speed under load from 8,000-24,000 rpm and soft start to reduce start-up torque for enhanced control
- Micro-fine, depth-adjustment ring provides precise depth adjustments in 1/64-inch increments and adjusts vertically for a constant switch/cordset location
- Adjustable, tool-free, steel motor cam lock makes depth adjustment and base changes quick and solid-locking
- Integral, through-the-column dust collection collects 95% of the dust and provides superior bit visibility
| Approach | What it offers | What to consider |
|---|---|---|
| Plunge router and shop-built jig | Adaptable to the router and project; uses a guided router and suitable bit. | You must build and align the jig, clamp the work securely, and validate the setup with test cuts. |
| Drill-powered commercial mortising jig | An alternative if you do not have a plunge router or prefer not to build a jig. Woodcraft describes the JessEm Zip Slot Mortise Mill. | Woodcraft’s article reports that the Pocket version cuts 1/4-inch-wide mortises and that the standard version offers several width choices. Verify current model specifications and compatible tenons before buying. |
| Dedicated Domino joiner | A purpose-built joiner cuts mortises for shaped, compatible loose tenons. The sources describe speed and accuracy advantages. | Mortise settings and tenon sizing are system-specific, and the available settings may be limited. Compare the current models, mortise range, compatible tenons, cost, and how often you will use the tool. |
Current prices and availability for these options are not established here. Product details can change, so check the maker’s current specifications before selecting a system.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Make or buy the loose tenons
Shop-made tenons let you size the stock to your test mortise. WOOD Magazine describes using hardwood stock, fitting its thickness to the mortise, rounding the long edges to match the mortise ends, and cutting the pieces to length while leaving room for glue.
Rank #3
- BOSCH POWER TOOLS ROUTER'S 12-AMP MOTOR IS POWERFUL, AND IT INCLUDES ADJUSTABLE SPEED SETTINGS
- CONSTANT RESPONSE CIRCUITRY STABILIZES START-UP TORQUE ON WOOD ROUTER
- ADJUSTABLE SPEED DIAL (8,000-25,000 RPM) ALLOWS USER TO SET THE OPTIMAL SPEED ON THIS WOOD WORKING BOSCH TOOL
- MICROFINE BIT-DEPTH ADJUSTMENT ALLOWS THIS HAND ROUTER FOR WOODWORKING TO GIVE FAST, PRECISE BIT-DEPTH ADJUSTMENT.
- PLUNGE BASE GIVES PRECISE DEPTH CONTROL, IDEAL TO USE AS A PLUNGE ROUTER
Pre-made tenons are another option, particularly when using a dedicated mortising system. Check dimensions and system compatibility before purchase; tenons made for different systems should not be assumed interchangeable.
Quick Recap
Best Value
- 【6.5 AMP MOTOR & 6 VARIABLE SPEEDS】 Power through your projects. Driven by a robust 1.25 HP (800W) copper motor, this variable speed palm router delivers 15,000 to 32,000 RPM. Unlike basic single-speed models, the 6-level dial lets you match the exact RPM to your material. It ensures smooth, burn-free finishes on various woods, providing continuous power for demanding routing and trimming tasks.
- 【TRANSPARENT BASE & PRECISION CONTROL】 See every cut clearly. This versatile woodworking router tool features an impact-resistant clear base for an unobstructed view of the trimming edge. Engineered for precision, it combines a quick-release locking lever with an easy-to-read depth scale. It guarantees stable, slip-free adjustments for flawless grooving, edge profiling, and laminate trimming.
- 【ERGONOMIC GRIP & QUICK MAINTENANCE】 Built for lasting comfort. This compact wood router features a rugged polymer housing and a vibration-absorbing rubberized grip to minimize hand fatigue. Designed with optimized cooling vents and externally accessible carbon brushes for quick maintenance. Furthermore, it includes a clear dust hood that connects to standard shop vacs for a spotless workspace.
- 【15-PC CARBIDE BITS & MULTI-USE GUIDES】 Expand your capabilities instantly. This router tool for woodworking pairs a premium 15-piece Tungsten Carbide bit set with a clever 2-in-1 edge/circle guide and a roller guide. Perfect for edging, chamfering, and surface finishing, it allows beginners and DIYers alike to tackle custom cabinetry, sign carving, and home crafts right out of the box.
- 【COMPLETE STARTER KIT & IDEAL GIFT】 Grab and go anywhere. This complete handheld router tool package includes everything needed for door hinges or home repairs. Housed in a custom-molded carrying case, the kit features: 1x 800W router, 15x bits, edge/circle/roller guides, a dust hood, 2x collets (1/4" & 6mm), wrenches, and spare brushes. It is the perfect holiday gift for any woodworker or DIYer!
Rank #4
- Powerful & Stable: Powerful 800W compact router delivers excellent power to meet variety applications, heavy-duty cast aluminum motor housing and fixed base are engineered for increased durability. 1 x Plunge Base and 1 x Tilt Base are included.
- Smooth Soft Start: Routers goes from standstill to maximum speed very quickly, creating less torque. Soft-starting helps prevent this palm router from jumping around in your hand, giving you much better control.
- Large Speed Range: The motor's speed range 10,000-30,000 RPM, features Constant-Response Circuitry for clean, consistent results. Variable Speed enables a bit of speed to be optimized for changing materials.
- Ergonomic Design: Vibration-reducing cast aluminum housing along with soft-grip handles reduce vibration for increased comfort and control. Dust hoods for vacuum to make job-site superior clean. Perfect for wood processing, furniture manufacturing and other industries.
- Accurate & Precise: Adjustable rack-and-pinion depth control for more precision cutting. Graduated in both clear inch and mm depth scales easy-to-read. Quick release cam lock system for easy depth adjustments and base removal/installation.
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.
