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Leigh 18" Super Jig
Innovation and quality at a budget saving price
Text, photos and video by Tom Hintz
Posted - 8- 13-2009
The Leigh 18" Super Jig is a new generation joint making tool spawned by the famous Leigh D4 series dovetail jigs. While Leigh did employ slightly more economical materials and designs, their penchant for innovation and user-friendly function remain intact. The Leigh 18" Super Jig lets you cut through and half-blind (both variably spaced) dovetails with ease. Plus, you can cut half-blind pin and tail boards in one pass for production-type runs! The Leigh 18" Super Jig also makes sliding dovetails and box joints (in both 5/16" and 5/8" widths, adjustable in 0.002" increments!) without having to buy expensive attachments - and they actually fit! Throw in the very trick Leigh E Bush (patent pending) and custom fitting finger (and sliding dovetail) joints has never been easier.
While the Leigh 18" Super Jig covers most woodworking capacity needs, Leigh offers the Super Jigs in 12" and 24" versions with identical features. Also, the Leigh 18" Super Jigs are not limited to one bit size. You can choose from five half-blind bit sizes to cut half-blind joints in the depth that best suits your project!
The Leigh 18" Super Jig body is made from a precision aluminum extrusion that is engineered to be strong and flex resistant. The body is fitted with tough glass filled end caps that have integrated screw slots for securing the Leigh 18" Super Jig to a board. That makes clamping it to a bench simple and Leigh even includes the necessary square drive screws for attaching it that use the included driver that adjusts the guide fingers. The end caps also have built-in storage for the E Bush wrench and a spacer rod.
The top and front surfaces feature abrasive strips that help keep the wood stable during routing operations. Leigh includes a pair of lever-actuated clamps that secure the wood to the top and front surfaces quickly and securely. The clamps apply their pressure to spring loaded extruded aluminum bars that spread the clamping pressure across the wood evenly.
The body uses sidestops that are installed during assembly. The instructions are clear on aligning the side stops correctly and when followed, produce a jig that cuts perfectly aligned joints. While paying attention to the instructions should be a no-brainer, past experience tells me to repeat this point - read and follow the instructions!
The top side stops are undercut for working with rabbeted drawer fronts. This simple undercut prevents having to use shop-made spacers on most common rabbet sizes.
Guide Fingers & Scales
The Leigh 18" Super Jig does not have the split finger assemblies found on the Leigh D4R Dovetail Jig but rather uses solid fingers that can be placed wherever you like across the board for through and half-blind joints to give projects your own personal touch. The fingers are locked in place with the Leigh cam screw that is operated with the included square drive wrench.
The Leigh 18" Super Jig fingers are specially shaped so they can make through and half-blind dovetails as well as finger joints. That eliminates the need to buy additional templates. Leigh also supplies special plastic runners that are used with the fingers. One is used as a fence for cutting sliding dovetails, while the other two are cut to use as bridges on wider half-blind finger spacing. They also include a round Stop Rod that acts as a limiter when cutting one-pass half-blind dovetails. Leigh also includes a multi-use spacer that is used during setup for cutting finger and one-pass half-blind dovetail joints with instructions on its use covered fully in the user guide.
At either end of the guide finger bar are scales that make it easy to adjust the assembly for the type of joint being cut. Each scale face has clearly printed numbers along with an icon that shows the operation they correspond to. Leigh also added arrows when appropriate that indicate which direction tightens or loosens that specific joint fit. The active scale is always right side up while the other scale on each face is upside down when not in use. This is a proven system carried over from the Leigh D4R Dovetail Jig and helps you to make ultra precise joints or tiny corrections very quickly.
E Bush & Bits
The secret behind the finger joint-tuning capability of the Leigh 18" Super Jig is their innovative E Bush that is included with the kit. This guide bushing has an adjustable collar that is elliptical rather than round. An included pin wrench turns the center piece to modify the active diameter for fine-tuning finger joints.
The collar is elliptical by 0.020" allowing you to "tweak" finger joint fit in tiny increments down to a remarkable 0.001"! The E Bush is also used to adjust the fit of sliding dovetail joints. The face of the E Bush even has an engraved scale along with arrows indicating which way to turn it for making the joint "tighter" or "looser". The manual shows how to install the E Bush initially so it is aligned with the router properly. If you are paying attention, you can't go wrong!
Leigh even put their engineering touch on the nut that secures the E Bush in place. Rather than the knurled ring that can be very difficult to tighten properly on some routers, Leigh devised a star-shaped locking ring. The "points" of the star are actually rounded and make it much easier to get the E Bush sufficiently tight once adjusted.
The E Bush supplied with the Leigh 18" Super Jig is designed to fit the popular Porter Cable style stepped baseplate opening. However, Leigh has adapters available to accommodate many other popular routers. See the Leigh Jigs site for details and listings.
Along with the E Bush 3 high-quality carbide-tipped bits are included with the Leigh 18" Super Jig. All of these bits have 8mm shanks that are preferred because of their superior strength over 1/4"-diameter versions. These bits are more stable in operation so produce a better cut. Over the years I have used several Leigh bits and can attest that they work well and last a very long time.
Leigh includes the #80-8, 8-degree dovetail bit that is commonly used for through dovetails. The #140-8, 5/16"-diameter straight bit is also used to make through dovetails as well as box joints on the Leigh 18" Super Jig. The last is the #120-8, 14-degree dovetail bit used for half-blind dovetails.
To make the 8mm shanks compatible with common 1/2"-capacity collets, Leigh includes a reducer. This finely machined piece fits into the 1/2"-capacity collet, creates a 8mm-diameter hole yet allows the collet nut to tighten around the bit to secure it. I'm not sure how but the Leigh reducer allows self-extracting collets to remain self-extracting.
User Guide & DVD
Leigh has been my favorite instruction manual producer for years and the user guide packed with the Leigh 18" Super Jig is no different. Clearly written text surrounds equally clear illustrations that walk you through the Leigh 18" Super Jig operations. The large pages mean that Leigh can present the graphics in a large enough scale to be easily seen and understood. They want you to be able to actually use this information, not just be able to say it's there!
Another important point about the Leigh 18" Super Jig user guide is the spiral binding. Though considerably more expensive to produce, this binding lets the pages lay flat without you having to weight them down. This relatively costly form of binding makes the Leigh 18" Super Jig user guide far easier to use, which directly translates into more woodworkers actually using it.
Leigh also includes a full length DVD that describes all of the Leigh 18" Super Jig operations in detail. The DVD has helpful tips throughout that help you cut more accurate and cleaner joints. A common complaint about dovetail jigs is chipout, which incidentally has nothing to do with any dovetail jig but everything to do with router direction. The Leigh DVD shows (among many other things) the correct path to use while routing joints to virtually eliminate chipout.
Box Joints & Sliding Dovetails
Another oddity about the Leigh 18" Super Jig is that it also makes finger (box) joints and sliding dovetails without having to buy attachments. All necessary pieces are supplied with the Leigh 18" Super Jig kit and full instructions for both joint styles are included in the user guide.
Finger joints have always been a problem for woodworkers, in particular cutting finger joints that actually fit. This is where the Leigh E Bush with its adjustable elliptical collar saves the day. This innovative guide collar lets you fine-tune finger joints so that they fit the way you want them to. That fact that this finger joint capability is a standard feature of the Leigh 18" Super Jig is itself remarkable.
This Leigh 18" Super Jig was reviewed with the innovative VRS (Vacuum and Router Support) accessory kit. Though surprisingly simple appearing, it is obvious that Leigh invested a bunch of engineering time figuring the VRS out. The result is that it works great, catches a remarkable amount of the debris and adds support to the router during the dovetailing procedure. And, the VRS kit attaches to the Leigh 18" Super Jig without modification to the jig. Leigh has VRS kits for all of their dovetail jigs.
The VRS chute slides along under the support bar and is always aligned with the router thanks to a pair of spring wire guides. The guides are fully adjustable to fit virtually any router you may have. The router is not attached to the VRS in any way so between cuts it can be parked to one side or removed from the Leigh 18" Super Jig entirely with ease. Also, the VRS bar is held in place with strong magnets so it also can be removed without tools for making adjustments to the jig. Each end of the VRS bar has loops molded in that allow hanging it on a hook or screw on the bench while removed for setups.
The VRS kit includes two adaptors that fit popular vacuum hoses from 1" to 2 1/2". The VRS can be used with shop vac's or purpose designed woodshop dust collectors. The VRS kit for the Leigh 18" Super Jig sells for about $74.00 but considering how well it works, this is a small price to pay! I was suspect of the VRS when I first saw it but after using it extensively on my Leigh D4R Dovetail Jig I won't use any Leigh jig without the VRS!
In the Shop
Setting the Leigh 18" Super Jig up is neither time consuming nor difficult. The user manual supplied with the Leigh 18" Super Jig is well written and illustrated to guide you through the process step by step. All you have to do is actually use it!
The one place I can promise the more hurried (or just impatient) among us will get caught is in aligning the side stops. The manual clearly describes the process and talks about using perfectly square pieces of wood to do it. If you fudge on this one point of setup, no dovetail jig will work right. Take your time, use square (really square, not sort of square) pieces of wood, follow the instructions and the side stops will produce nicely aligned joints. The whole process of installing and aligning the side stops took me all of 15-minutes, which includes time for shooting photographs.
At first I thought that the Leigh 18" Super Jig one-piece fingers would impose a design limitation. This concept does limit you slightly as compared to the split fingers of the Leigh D4R Dovetail Jig but throughout the evaluation the one-piece fingers were easy to use and made designing eye-catching dovetail layouts easy.
Making all of the joints the Leigh 18" Super Jig is capable of turned out to be surprisingly simple. The user guide literally walks you through the entire process or setting up and cutting each joint variation. If you take the time to follow those instructions you will be cranking out nice fitting dovetails very quickly. This can be an especially important feature because for many of us, cutting dovetails is a more occasional task. Clear, easy to follow instructions help refresh the memory.
The one pass dovetail capability is handy, especially for larger jobs where lots of drawers or boxes have to be made. Once set up you can crank out nice fitting joints very quickly. As with the finger joint, the one-pass half-blind dovetail spacing cannot be varied which makes board width a factor. Leigh includes a comprehensive chart for both joint styles that help you determine the needed board width easily.
The E Bush is a nifty piece of Leigh thinking. Finger joints (box joints to some) have always been a source of frustration, particularly in getting a nice fit. Here again it takes setting the E Bush up right but follow the instructions and you can dial in your finger joints just the way you like them and do it quickly.
The VRS dust/support system is so effective it has become a must-have in my shop. I would have never thought it possible to catch so much of the debris generated by a router while cutting dovetail joints but he VRS does just that. Eventually I will learn not to doubt anything Leigh thinks up.
The Leigh 18" Super Jig is a surprisingly versatile dovetail jig that will let you add all of the common dovetail variations to your projects and custom design their spacing to let your creative side show through. With a street price of $289.00 (8-12-2009) the Leigh 18" Super Jig is another great value from the gold standard jig manufacturer. Add the VRS system (and you should) with a street price of $67.00 (8-112-2009) and you not only make nifty dovetails, your shop (and you) stay way cleaner!
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