Is It Compatible with my router table?
Router tables are typically used with a bearing or fence, however, the Leigh RTJ400 is guided around a guide bushing mounted in the router table. Leigh eBushes (guide bushings) are designed around the decades-old Porter Cable/Black & Decker industry standard. Therefore, you will need an insert ring to fit the eBush to your router table or router plate. All major router table and router lift manufacturers including JessEm, Incra and Kreg include a 1-3/8″ diameter counter bore insert ring as part of their insert ring sets, so there’s no problem with compatibility.
To fit the eBush to your router table insert plate, you need a 1-3/8″ diameter counter bore insert ring. JessEm, Incra and Kreg all produce them as standard.
Precision and Accuracy of the RTJ400
Dovetail and box/finger joints are all about precision and accuracy whether cut by hand or using a router. With the RTJ400’s elliptical bushing capable of adjustments down to .001″ it’s obviously necessary to make sure the rest of your router table is set up properly.
What Else Should You Consider?
The only real alternative to the Leigh RTJ400 for producing dovetail joints and box joints on the router table is the Incra LS17 Super System Router Fence, but it’s not really a comparable alternative because the Incra LS17 is a complete fence and positioner system, rather than a dovetail and box joint jig. It also costs almost twice as much at well over $600.
If you are only interested in routing box joints only you should consider the INCRA I-BOX Jig for Box Joints which is substantially cheaper at just under $150, but if you want to cut dovetails as well, the Leigh RTJ400 Router Table Joinery Jig is the only real option.
Leigh RTJ400 Compared To Bench-Mounted Dovetail Jigs
As an alternative to traditional bench-mounted dovetail jigs, the LEIGH RTJ400 Router Table Joinery Jig is a great option, eliminating the need to hold and maneuver your router through the fingers of a traditional jig. Supporting a heavy router as you work with a traditional jig without the router tipping is a real consideration to the point where Leigh themselves produce an optional router support bar for their traditional dovetail jigs. Using the LEIGH RTJ400 on your router table eliminates the problem, allowing you to concentrate on cutting the joint rather than supporting the router.
Priced at $329, the Leigh RTJ400 sits in the middle of the price bracket for traditional dovetail jigs. The only downside compared to a top-of-the-range dovetail jig like the Leigh D4R-Pro is that you haven’t got the unlimited versatility that allows you to cut variably spaced joints, although there are very few dovetail jigs that have either. You can rout a much bigger variety of joints on the RTJ400 than you can on a standard dovetail jig like the Porter Cable 4212.
The RTJ400 also doesn’t take up much shop space as it can be hung on the wall out of the way when not being used. Bench mounted dovetail jigs are a lot bigger and more cumbersome.
If you want an alternative to a traditional bench-mounted dovetail jig, you should give the LEIGH RTJ400 Router Table Joinery Jig serious consideration. It’s easy to set up and makes precise, accurate joinery easy on your router table. It’s extremely versatile and you can cut full & half pitch through dovetails, half-blind dovetails and box joints (finger joints) in a number of different sizes on boards up to 16″ wide. Even though the jig can cut many different kinds of joinery, each setup is simple to achieve, and it’s straightforward to switch from one setup to another when needed. The LEIGH RTJ400 Router Table Joinery Jig has all the usual attention to detail and build quality that characterize all of Leigh’s woodworking products. Highly recommended.