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Leigh D4R 24"Dovetail Jig
Making the Gold Standard "Golder"
Text, photos and video by Tom Hintz
Posted - 3-31-2009
Whenever a new version of a favorite tool emerges I worry about the "improvements" benefiting corporate bottom lines way more than making the product better. The Leigh D4R Dovetail Jig turns out to be the poster boy for how to legitimately improve an already great tool. Leigh really has made their famous dovetail jig better without compromising quality or ease of use. There are a bunch of companies out there that need to grasp this concept.
The Leigh D4R Dovetail Jig is based on a tough, high-quality one-piece aluminum extrusion that has been CNC (computer numerically controlled) machined on the top and front faces. That insures that those crucial surfaces are precisely aligned and square to each other, which contributes in a big way to the overall accuracy of the Leigh D4R Dovetail Jig. The ends of this body are fitted with precision cast caps that include provisions for bolting the jig to a board. That makes clamping the Leigh D4R Dovetail Jig to a solid work surface quick and easy. They even include the necessary nuts and bolts for securing the jig to the board!
A new feature of Leigh D4R Dovetail Jig body is machined-in sidestops that align the boards to the left and right for dovetailing. The previous D4 jig version had adjustable sidestops that worked perfectly when they were adjusted correctly. Unfortunately too many woodworkers did not use boards with truly square edges to set the sidestops up. Also, the top sidestops on the Leigh D4R Dovetail Jig are undercut so they are compatible with rabbeted drawer fronts and square-edged stock. The offset between the top and front mounting positions is built in and is always correct.
The new design of the Leigh D4R Dovetail Jig body makes it possible to route through dovetails in material up to 1-1/4"-thick or as thin as 3/8" or even 1/8"-thick! The User Guide describes the setup for working with very thin material under 3/8"-thick beginning on page 74. Incidentally, Leigh bits #50-8 and #60-8 (not included) are used with this thin material.
The workpieces are secured against the textured surfaces on the jig body with extruded aluminum bars actuated by tool-free clamping levers. The machine-textured surfaces on the jig body dramatically reduce the chances of slippage. To make inserting the wood easier, the clamping bars are spring loaded to move outwards when clamping pressure is relaxed.
Super tough glass-filled nylon levers apply and relieve the clamping pressure on the bars. These handles screw up and down on bolts to accommodate various stock thicknesses. Flipping the handles 90-degrees applies or relieves the clamping pressure. Each of the levers interacts with a special stepped washer at its base that provides another level of fine thickness adjustment that can help position the handles so they are out of the way. This entire clamping system is very effective, completely tool-free and easy to use.
The Leigh D4R Dovetail Jig uses infinitely adjustable fingers rather than a fixed template. The fingers can be placed anywhere on their mounting bars to create virtually any dovetail pattern you like. The only limiting factor is the width of the wood being used. These guide fingers make it easy to get a half pin at the sides of the joint. The guide fingers are locked in place individually with an internal cam that is turned with the provided square drive hand wrench. Because the same guide finger layout cuts both the pin and tails, setup is done once and the joint fits perfectly. The entire finger assembly is flipped over (front to back) to change from pins to tails mode.
Dummy Alert: The Leigh D4R Dovetail Jig guide fingers are made from a relatively soft zinc alloy that while plenty strong to function as designed, will usually give up before an expensive router bit. This can be important for those who disregard the repeated warnings about letting the router stop completely before trying to lift it out of the jig. In case you are wondering, the fingers can be purchased separately (there is a left and a right) and cost about $7 each. And, I have purchased three of them over seven years...... That's all you need to know.
Leigh includes three plastic strips. One fits into the ends of the guide fingers to form a guide for routing sliding dovetails and the other two are material for making bridges between fingers. The bridges are helpful with wider dovetail patterns where the fingers are far enough apart to allow the guide bushing to slip between them and cause a major error.
Tip: Every time you cut a new set of these bridges save all in that size in a small plastic bag so you can use them later. Most woodworkers will develop a few commonly used bridge sizes that can create a bunch of great looking dovetail patterns.
User-friendly scales on either end of the finger assembly make setting up and "tuning" the Leigh D4R Dovetail Jig easy. Each scale has two sections, one for through dovetails and another for half-blinds. Identifying icons in each section and only one being right side up when the guide
finger assembly is oriented correctly make it clear which type of joint is in use. Flipping the guide finger assembly end over end changes between half-blind and through dovetails. Flipping the guide finger assembly over front to back changes between pins and tails mode when cutting half-blind or through dovetails. The scales are available in standard or metric versions.
When cutting through dovetail pins, moving the finger assembly forward or back on the scale controls joint fit. In half blind mode, moving the finger assembly front to back controls the depth of the pins into the tail board. Printed images of the scales are provided in the User Guide so you can record commonly used settings to make future setup easier and faster.
The only trick to using the Leigh D4R Dovetail Jig scales - and this is explained in the User Guide for those who read it - is to read the scales from directly over it. This is common to virtually all measuring devices. If you do not read the scales from straight on, you get a distorted view (parallax) of the etched line and the scale numbers. At an angle (even a small one) it can appear that a number is right on the line but move to directly over it and it can be surprisingly far off. If you want dovetails to fit correctly you have to read the scales correctly. Besides, if you take the time to read these (and all) scales right, the woodworking world in general functions more smoothly.
Leigh set a new standard for instruction manuals with the version they developed for the original D4 jig. I (and many others) have always considered this to be the best-written, best illustrated and best thought out instruction manual in the business. The User Guide packed with the Leigh D4R Dovetail Jig retains all of the above qualities and praise.
The Leigh D4R Dovetail Jig User Guide is loaded with high-end illustrations printed in a size that lets you actually see what is going on even for those of us with aging eyes. The text is extremely well written in a style designed to make the information clear to the reader rather than demonstrate that the author actually stayed awake during the big word part of English class. The User Guide is divided into logical chapters that make finding the needed information simple.
Leigh includes a Hints and Tips chapter that has answers to commonly asked questions. I consistently get emails from Leigh jig owners asking things that are fully covered in this chapter. These same email questioners are often surprised to learn that what they needed to know was right there in front of them all along. If we could only figure a way to get people to use the information they already have.....
Another very nice feature of the Leigh User Guide is the spiral binding. This type of backbone allows the User Guide to lay flat on the bench with one or two pages showing without having to weight the pages down with anything. This binding is far more expensive but you will quickly learn to appreciate Leigh spending those extra dollars.
In addition to the Leigh D4R Dovetail Jig itself they include a #80-8, 1/2'', 8° dovetail bit, a #120-8, 1/2'', 14° dovetail bit and a #140-8, 5/16'' straight bit, all with 8mm shanks. These bits allow making through dovetails in materials from 1/2" to 13/16"-thick but Leigh has bits available to cut through dovetails in wood up to 1-1/4"-thick and half-blind dovetails in wood up to1/12"-thick! Leigh also includes a 1/2'' to 8mm collet reducer that adapts your 1/2"-capacity router collet. A 7/16'' OD guide bushing is also in the kit and fits the very popular Porter Cable stepped baseplate opening. Leigh offers many guide bushings adaptors to fit most routers on the market but replacement baseplates with the Porter Cable stepped opening are available from aftermarket suppliers for virtually all popular router brands and models. Leigh also offers similar guide bushing with a 5/8" OD for use with bits with 1/2"-diameter shanks.
The Leigh AC D24 Accessory Kit was used with the Leigh D4R Dovetail Jig throughout this review. This kit includes the VRS D24 dust collection system and the #2411-8, 12 piece Leigh Router Bit set.
The VRS D24 vacuum and router support system is a bolt-on accessory that keeps the work area much cleaner than I would have thought possible when dovetailing. Installation is limited to screwing an arm onto each of the finger support arms. The bar that supports the dust collection shroud attaches to those arms with powerful rare earth magnets. This system is as simple to install and use as it is effective.
The dust shroud slides along under the tough extruded aluminum support bar, which puts its inlet opening at the perfect height to catch the debris made by the dovetail bit. A pair of wire arms surround the router and move the collection shroud with it while you cut dovetails. The outlet port on the dust shroud can be sized to accommodate 1", 1-1/4", 1-3/8" and 2-1/2" hoses with included adapters.
Because the support bar is attached with magnets, it is easy to position or remove for making adjustments to the Leigh D4R Dovetail Jig. This support bar is adjusted during installation so that it is even with the top of the guide fingers so the router is always square to the wood being cut. This additional support makes routing clean dovetails easier yet. It also allows you to "park" the router to the unused side of the Leigh D4R Dovetail Jig when changing workpieces clamped to the vertical surface.
The 12 pc. 8mm shank bit set includes bit numbers: #50-8 (1/4", 8-degree), #60-8 (5/16", 8-degree), #70-8 (3/8", 8-degree), #75-8 (7/16", 8-degree), #90 (11/16", 8-degree, 1/2" shank), #100 (13/16", 8-degree, 1/2"-shank), #150 (7/16" straight, 1/2"-shank), #160 (1/2"-straight, 1/2"-shank), #101-8 (1/2", 10-degree), #112-8 (1/2", 12-degree), #128-8 (1/2", 18-degree) and a #172-8 1/2" to 8mm collet reducer. If you can't dovetail your project with the Leigh D4R Dovetail Jig and this bit set, it probably should not be dovetailed.
All of the bits have high-quality carbide cutting edges that have been finely honed on a 600-grit diamond wheel. These bits also have 1-3/4" -long shanks to work best with the guide fingers. Leigh makes their bits in 1/4"-diameter shanks but the 8mm shanks are far more popular because the 58-percent increase in shank mass makes them much stiffer and produce better results. In my experience, they also last longer, probably because of the reduced vibration.
In the Shop
Assembling the Leigh D4R Dovetail Jig went very quickly and without difficulty because the procedure is simple and the instructions are very easy to follow. Because the sidestops are machined into the jig body the only real alignment procedure has been eliminated. That means you are ready to start making dovetail joints very quickly.
Adding the VRS D24 dust collection system was also very easy and required no modifications. Leveling the support bar with the finger assembly was the most complicated portion of the procedure and took all of two minutes.
Using the Leigh D4R Dovetail Jig is much easier than most expect. The User Guide really does walk you through the process of cutting through, half-blind, rabbeted half-blind and sliding dovetail joints. You just have to take the time to use it. The accuracy with which the Leigh D4R Dovetail Jig is designed and made translates directly into perfect dovetails. There will always be some fine-tuning with router bit height but experience with the jig and seeing what those adjustments do will make this an increasingly quick process.
The machined-in sidestops makes setting the Leigh D4R Dovetail Jig up for use easier and will prevent one of the major user error causes of bad dovetails. With these stops, if you use correctly dimensioned wood with square ends, making dovetailed boxes or other projects is a snap.
Another big plus for the Leigh D4R Dovetail Jig is the variable guide fingers that let you decide what your dovetails will look like. Once you get used to the idea that the Leigh D4R Dovetail Jig will cut whatever you tell it to perfectly, you can focus on being creative and putting your own touch on the projects you build.
While evaluating the Leigh D4R Dovetail Jig I made through, half-blind, rabbeted half-blind and sliding dovetails without issue. The Leigh D4R Dovetail Jig is so accurate that if you follow the instructions in the User Guide, cutting great looking, tap-together, super strong joints is all but guaranteed. With a little experience you will find that cutting perfect dovetails is also surprisingly fast and easy. And, with the accessory bit set you can cut all of those dovetails in virtually any wood thicknesses that may be found in the woodworking shop.
The dust collection attachment is not 100-percent effective but it is very close to it. I spent most of an afternoon cutting dovetails and the pile of debris that had found its way to the floor did not fill the dust pan once. Without the dust attachment I would have had a larger pile of wood dust in my pockets alone! This is a remarkable piece of thinking that you will quickly learn to appreciate.
The bar that the dust system rides on also gives the router an additional bit of support that really does make getting perfect dovetails easier by keeping the router upright and preventing rocking it front to back. That extra support goes a long way to making better dovetails.
Though I would not have thought it possible a few years ago, the Leigh D4R Dovetail Jig is a step up from the Leigh D4 that made this company famous. The improvements to the Leigh D4R Dovetail Jig are effective and really have made what many consider to be the best dovetail jig ever made easier to use and even more accurate.
The Leigh D4R Dovetail Jig has a street price of $499.99 (3-27-2009) and you rarely see it on sale because they are the best selling quality dovetail jig already. There is a very good reason why the Leigh D4R Dovetail Jig is so popular - it is the best I have ever tried and the User Guide is also the best. If you need a dovetail jig and want maximum quality, flexibility and value for your money the Leigh D4R Dovetail Jig just could be the only legitimate candidate on your must-see list.
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