Techniques To Master Dovetail Joints - Popular Woodworking
Techniquesto MasterDovetail Joints:Beyond the Basicswith a Router
Photo by Al ParrishSlidingDovetailsTwo router bits with guides and a simpleshop-made jig make three variations ofthis joint a snap.ne of the defi ning features of 17th- and 18thcentury furniture is the dovetailed horizontal casedivider. Case dividers are the rails that separate thedrawers, or the door and drawer sections. Attaching thesedividers to a case’s sides using sliding dovetails is probablythe strongest way possible to assemble a carcase.However, reproducing this detail is daunting to manywoodworkers. Not only is a sliding dovetail seen as complexjoinery, but it can be made in different ways. The basic sliding dovetail, shouldered sliding dovetail and through slidingdovetail (shouldered or not) are just a few of the options.Oby Glen HueyGlen builds custom furniture in Middletown, Ohio, for MalcolmL. Huey & Son, teaches woodworking and is a contributing editor for Popular Woodworking. He also is the author of two books,“Building Fine Furniture” and “Fine Furniture for a Lifetime” (PopularWoodworking Books). See more of his work at hueyfurniture.com.popwood.com
9/16"BASIC SLIDING DOVETAILThe simplest option in sliding dovetails. The socket ortrench requires only a single pass with the dovetail bit.9/16"From Dado to Dovetail3/16"SHOULDEREDSLIDING DOVETAILThis joint adds a shoulder to the dovetail andrequires you to make a first pass with apattern-making straight bit. Then thedovetail bit (set at the same depth as onthe joint above) is used to cut the dovetail.3/4"Each type of sliding dovetailrequires a different jig. I’ve useda variety of these jigs in my manyyears of building reproductionfurniture. Some jigs capture therouter base and are specific to acertain router bit. If you need touse more than one bit (to make ashouldered dovetail, for example)this can be a problem – unless youown two identical routers.Other jigs are as large as theentire case side, making themhard to handle and store. But I’vefound a better way. Using a 3 4"top-bearing flush-trimming bit(often used for pattern routing),a 3 4" dovetail bit, a template guidewith a 3 4" outside diameter anda shop-made straightedge, any ofthese joints can be made easily.3/16"THROUGH SLIDING DOVETAILA more complicated joint, this is made in three steps.First the straight bit forms the shoulder, thenthe dovetail bit shapes the divider pin. The finaldovetail socket is hand cut to avoid tear-out.POPULAR WOODWORKING August 2004To understand how this works,let’s start with a simplified version of the joint: a dado. With astraightedge clamped across a cabinet side and a flush-trimming bitin your router, you can cut a dadofor case dividers or web frames.Simply position the straightedgewhere you want your dado, set thedepth of cut on your router andplow it out. The bearing on the bitfollows your straightedge.By using a dovetail bit witha template guide and this samesetup, you can use the straightedge to make the basic slidingdovetail shown above left.Use a template guide that hasthe same outside diameter as yourdovetail bit to make measuringsimple. Next, clamp your straightedge exactly where you want thesliding dovetail to go.Set the proper depth for thebit, (9 16" in 3 4" material, for example) then rout the dovetailtrench or socket in a little further than the width of the divider.The trench doesn’t need to extendall the way across the side. Butbecause the dovetail trench willhave a rounded end, the trenchmust extend a little further so thesquare-shouldered tail on the divider will fit.Two-step Shouldered JointsA shouldered dovetail is ideal forcasework that uses web frames,which support drawers. Thestraight shoulder, which supportsthe web frame, is cut just as youwould cut a basic dado.First align your straightedgeas you did with the basic slidingdovetail. With a 3 4"-diameterflush-trimming bit in your router,plow out the dado to 3 16" deep.Next, take your router with a template guide and dovetail bit, set itto 9 16" deep (without moving thestraightedge) and make the cutinto the case side. The cut shouldbe a bit longer than the width ofyour front divider.Thanks to the template guide(and keeping the straightedge inone fixed location), the dovetailportion of this cut is centered inthe dado automatically.Through Sliding DovetailsFor an even fancier look, you cancreate through sliding dovetails.These joints allow the end of thecase’s divider to be seen on theoutside of the case.Start once again by plowingthe dado as explained above. Youcould cut the socket portion ofthis joint with a router, but there’smuch less chance of tear-out if youcut the socket using a handsaw.If you go with this hand-toolroute, you should first cut the maleportion of the joint (called thetail) on the end of your horizontaldivider using the dovetail bit inyour router table. The process isexplained on the next page. Thenuse the tail to lay out the locationof the socket on the case side.Now you can saw out thesocket. Orient the saw to matchthe two tail sides, then cut in from
the front edge the width of the divider. Finally, chisel out the wastebetween your saw cuts.Don’t Forget the Tails!To make the mating joinery onthe dividers (the tails), I use myrouter table. Use the same dovetail bit you used to cut the dovetail sockets to form the tails toensure that the joint fits well. Setthe fence to adjust the size of thetails, cutting on both sides of thedivider. I like to sneak up on thefinal cut to ensure a snug fit.Set the bit to cut at the appropriate height for each joint style.For the basic sliding dovetail, thatheight should be about two-thirdsof the width of the case side. Ifyou’re making a shouldered dovetail, allow for the 3/16" shoulderdepth in your layout.The through dovetail is cutwith the height of the tail equalto the thickness of the case side (ifyou are adding a shoulder, remember to allow for the shoulder).Your through dovetail doesn’tneed to expose the whole widthof the divider. For example, youcan show only 3 4" on the sides ifyou like. After cutting the tails onboth ends of the divider, use a sawto trim the end 3 4" back from thefront of the divider on both sides.Then cut from the back of thedivider right at the point wherethe tail begins from the divider toremove the unneeded tail section.Repeat this cut on both ends.With the back portion of thetail removed, slide the divider intothe dado in the case and mark,then cut, the matching socket.Whatever Size You NeedWhile these techniques workgreat with the standard 3 4"-thickdrawer dividers that are commontoday, they also work with otherthicknesses of dividers by usingdifferent-sized template guidesand bits. The guides are readilyavailable in a wide variety of sizes,including 51 64" and 1" if you needthicker drawer dividers.You should consider usingsliding dovetails for any numberof woodworking tasks. The possibilities are endless. PWTHE STEPS TO A SHOULDERED SLIDING DOVETAILMaking a shouldered sliding dovetail beginsby cutting a dado in the case’s side. This dadois easily made with a pattern-cutting bit andthe right jig, which I call a straightedge guide.The bed of my jig, shown below, is simplytwo pieces of plywood cut slightly longerthan the width of the case side, then glued orscrewed together face to face. (Depending onyour router and bit, you might need only onethickness.) To complete the jig, screw a thirdblock to the underside of the straightedgeguide to hook it square against the front edgeof the case side. The hook should be sizedso you can clamp the jig in place withoutinterfering with the base of the router. As youcut the dado, make sure you move the routerin the correct direction (against the rotationof the bit) to keep it tight against the jig.Next, install a template guide in yourhandheld router and the dovetail bit. I shouldmention one important detail: To use atemplate guide that is the same diameter asthe pattern-cutting bit’s bearing collar (inthis case 3 4"), it will be necessary to attachthe guide first, then insert the bit afterward.Because of the identical diameters, the routerbase can’t be slipped over the bit with thetemplate guide in place. The guide is the samediameter as the collar to allow the dovetail torun exactly down the center of the dado cut.With the template guide in place and thedepth set on the dovetail bit, you’re ready tocut the dovetail socket, as shown below.With the socket created, it’s time to makethe mating tail on the end of the drawerdivider. Mount the dovetail bit in a routertable and run both sides of your divider onend between the fence and bit. You will needto make a few test passes to get the perfectfit. Note that I’m using a push block behindthe divider for safety and to stabilize the pieceduring the cut.— GHStraightedge guideDadoCase sideFront edge hooksover case sideThe first step involvesplowing out a simple dadowith a pattern-cutting bit,shown at right.Use a dovetail bit,shown at right, to makeyour shouldereddovetail socket.You can easily rout the tail of thejoint on your router table with thematching dovetail bit.popwood.com
Variable-spacedDovetails by JigTwo methods to movebeyond the limitations ofa fixed-space dovetail jig.Sby Don meansome of us just don’t have the time,patience or skill to produce hand-cut dovetailjoints and instead resort to one of the numerous dovetail jigs available on the market. However, at several hundred dollars apiece, noteveryone can justify the expense of a variable-space jig, such as the Leigh D4R. Even ifyou do happen to own this fine jig, for certainapplications I find it easier and more efficientto use a simpler jig. For example, when building cabinets or furniture for my workshop Iusually don’t want to spend the time settingup my Leigh D4 (yes, I do own one). However, I still want the dovetail joinery to haveaesthetic appeal.I’ve experimented with a number of dovetailrouter bit sizes and cutting angles and, usinga basic fixed-finger dovetail jig, have refinedtwo techniques that greatly improve the overallaesthetics of the resulting half-blind dovetailjoint. In addition, with a bit of planning, andwithin certain limitations, it is even possibleto create “variable-spaced” half-blind dovetailswith this “fixed-finger” jig.Dovetail Jig GeometryRig your jig. If you don’t want tohand cut dovetails you can comeclose to the look with these techniques and a fixed-finger jig. Popular Woodworking December 2007In order to fully utilize these techniques, it ishelpful to have an understanding of the geometry surrounding the dovetail joint producedby the fixed-finger jig. Although jigs of thistype generally operate the same way (that is,the pins and tails are produced in a single
operation) not all of them have the same geometric characteristics. For example, the Porter-Cable and Hartville jigs are similar, whilejigs by Rockler, Jet and Woodtek have slightlydifferent characteristics. For this article, Iworked with the Porter-Cable 4112 dovetailjig equipped with a 1 2" half-blind dovetailingtemplate. However, it should be possible toapply this technique to just about any fixedfinger dovetail jig, once you understand thebasic geometric relationships.When using a fixed-finger jig, the dovetail bit diameter and center-to-center fingerspacing are the critical dimensions that control the geometry of the dovetail joint. Thekey geometric relationship for the joint is theamount of overlap or interference betweenthe tail and the pin.This relationship is determined by (1) thecenter-to-center finger spacing, and (2) thediameter of the dovetail cutter. The slope orangle of the dovetail bit is secondary to thisrelationship. In fact, this is what we are goingto “play with” in order to improve the appearance of the joint.Adjusting the depth of cut determines theamount of interference between the tail andpin, and determines the fit of the joint. Asthe angle of the dovetail bit is reduced, it isnecessary to increase the depth of cut in orderto maintain the proper tail/pin interference.This reduced or slighter angle, as well as theincrease in the depth, is the key to improvingthe appearance of the joint.For these types of fixed-finger jigs, therelationship between center-to-center finger spacing, cutter angle, diameter and, ultimately, cutter depth is defined by the followingformula:Depth of Cut {D-S/2} Tangent(a)where:D dovetail bit diameterS dovetail jig center-to-center fingerspacinga cutter angle (in radians)This formula provides the insight we areseeking. As you can see, for a given cutterdiameter and finger spacing, the cutter angleis inversely proportional to the depth of cut.As the cutter angle is decreased the depth ofcut must increase.This formula might be the end of our minormath lesson if we were cutting dovetails inmetal with a precision CNC mill. Unfortunately, we are cutting with tools that have avariety of associated built-in errors (routerand bit run-out, bushing and template fit and FOUFS DFOUFSmOHFS TQBDJOH"OHMF%FQUI PG DVUcritical dovetail dimensionsbushing/router eccentricity, to name a few).All these factors result in an effective increasein the diameter of the cutter.A 1 2" cutter will tend to act like a slightlylarger bit. With my equipment (the PC jig anda DeWalt 621 router) I found through trial anderror that all of these imperfections addedabout .010" to the bit diameter. In other words,a 0.500"-diameter router bit acts like a 0.510"diameter bit. This effective diameter shouldbe used to calculate the estimated depth ofcut provided in the preceding formula. (Note:Everyone’s tools are slightly different so youwill have to experiment to find the amountof variation in your setup.)most) the joint will look OK. Because there aretwo half-pins on each drawer side this allowsa total variation of 1 8" over the drawer side.The chart below lists the possible sizes underthis parameter.Most moderately priced dovetail jigsinclude a basic 1 2" diameter, 14º dovetailingbit. Under normal operation these cuttersproduce a “stubby” dovetail joint, with tailsapproximately 5 16" long. In addition, the 14ºangle of the tail is not very graceful.Although there are a variety of dovetailcutters on the market, only a few have theproper cutting geometry that will allow themto work with the typical fixed-finger jig.Seethe chart below for cutters I have found thatwork with this technique.A Simple ImprovementA basic improvement when using the fixedfinger jig is to simply substitute a 1 2"-diameter,8º cutter (such as the #80 bit for the Leigh jig)for the standard cutter. Set up the jig as younormally would by following the manufacturer’s instructions. The only change to the normal setup is the depth of cut – which should bePlanning the Width (Plus or Minus)For the majority of applications, the most aesthetic arrangement for half-blind dovetails isto end with a half-pin at the upper and loweredge of the drawer side (or tail board). Unfortunately, when using a fixed-finger dovetail jigthis requires the side of the drawer to be limitedto certain widths. Some planning is necessaryto ensure the joint ends on a half-pin. The Porter-Cable 4112 has a center-to-center fingerspacing of 7 8" so in theory, drawer side widthshave to be multiples of this dimension.But it isn’t necessary that the half-pins beexactly one-half the pin width. A typical 1 2"dovetail cutter will produce a throat width thatis approximately 3 8" (therefore the half-pinthroat width would be about 3 16"). As longas you are close to this dimension ( 1 16" atDrawer Side Width*multiplierOR (INCHES)MAXIMUMWIDTH(INCHES)25 831 243 851 461 8777 883 493 821 233 841 451 8667 873 485 891 223 435 841 253 861 471 8887 893 4* Note: This chart provides the typical drawerside widths that are possible when using thePC 4112 dovetail jig and similar jigs withequivalent finger spacing. When properly setup in the dovetail jig, these widths will result ina half-pin at each end of the drawer.Commercially Available Dovetail Bits That Can be Used in Fixed-finger JigsStandardLeigh (#101)incraLeigh (#80)1 2"17 32"1 2"Custom*17 32"0.510"0.542"0.510"0.542"1 2"Cutter diameterEffective diameter 0.510"Angle or slopeDepth of cut14 10 14 8 1:619 64"26 64"27 64"33 64"5 8"Most manufacturers make bits in the sizes listed above. * Whiteside will custom-make this bit (or anyother for that matter) for a price of around 200. It is only shown here to indicate what the characteristics of the “optimal” router bit for this technique would consist of – if you are prepared to pay for it!Lead Photo by Allen Singer and the Author; step Photos by the author; illustration by mary jane favoritepopularwoodworking.com
set to about 25 32". The actual length of the tailwill be about 17 32". However, when measuringthe cutter depth from the base of the router, itis necessary to take into account the thicknessof the finger plate (1 4" in this case).It will probably be necessary to fine-tunethe depth of cut by experimenting with somescraps of wood. Simply follow the jig maker’sinstructions for making these adjustments.Once you have fine-tuned the settings,you are ready to dovetail the final pieces. I liketo back (or climb) cut the inside edge of thetails to create a clean inside edge for the pinsockets. Proceed to cut the pins and tails asyou normally would, then assemble the joint.The longer tailed, slighter-angled dovetailproduced with this bit is an improvementover the standard cutter.‘Variable’-spaced JointsIt is also possible to create a variable-spaceddovetail joint with the fixed-finger jig. Again,it takes a bit of planning to ensure that thedrawer side ends on a half-pin. In addition,for certain drawer side widths it will only bepossible to create asymmetrical dovetails.Another consideration is the number of tailsthat will show in the assembled joint. I findwider tails with an “odd” number of pins tobe aesthetically pleasing.However, this imposes quite a limitationon the drawer widths that can be used. (If youlimit yourself to this convention, it will only bepossible to use the widths corresponding tothe even-numbered multiplier in the “DrawerSide Width” chart on page 73 – assuming youwish to end up with symmetrical tails.)The following procedure outlines howto produce a variable-spaced dovetail jointthat has two half-pins at the top and bottomof a 51 4"-wide drawer side and with a singlefull-pin in the center.As before, I used the 1 2"-diameter, 8º cutter for this example. Again, set up the jig as younormally would by following the manufacturer’s instructions – adjusting the depth of cutto about 25 32". (As before, it may be necessaryto fine-tune the depth of cut.) The sequenceof accompanying photographs illustrates theprocedure.Don Means is an amateur woodworker and spendsmuch of his free time in his shop (or as his wife refersto it, the garage) in Danville, Calif. He has an engineering background and has been woodworking seriouslyfor about 15 years – mainly constructing furniture andother woodcraft for family and friends. You can viewsome of Don’s completed work at: home.earthlink.net/ mbwoodworks/. Popular Woodworking December 2007Creating a Variable-spaced Dovetail Joint With a Fixed-finger JigSkip these sockets1Rough cut the tails. With the jig and depth of cut properly set, first take a back cut along thewidth of the drawer side. Then, as you normally would, start at the inboard end of the jig androut out the first tail socket. However, do not rout the next slot in the jig template. Instead skip overthe next two slots to the fourth slot. Rout out this tail socket, then again skip the next two slots andfinish up on the last slot (which should be the outside edge of the drawer side). As you look at thedrawer front there should only be two tail sockets routed in the drawer front (or pin board) andtwo “wide” tails that are roughly defined on the drawer side.4Finish the tail sockets
L. Huey & Son, teaches woodworking and is a contributing edi-tor for Popular Woodworking. He also is the author of two books, “Building Fine Furniture” and “Fine Furniture for a Lifetime” (Popular Woodworking Books). See more of his work at hueyfurniture.com. Sliding Dovetails Two router bits with guides and a simple
The DJ 300 Dovetail Jig is supplied with a standard 1/2" (12.7mm) dovetail template and will produce lapped dovetail and lapped rebated dovetail joints. The 15.7mm template guide bush and the 12.7mm (1/2") diameter x 104 Dovetail router cutter should be used and are supplied with the jig. Specification Min material thickness is 12mm.
dovetail bit: A V-shaped router bit for making dovetail joints; they come in various sizes. dovetail jig:A holding fixture and template for making dovetail joints using a saw or router. The fingers on the template not only guide the router bit, but also p
Your New Leigh Dovetail Jig Congratulations! You now own the world’s most useful and versatile joinery tool. The Leigh Dovetail Jig will help you cut an infinite variety of joints, and all of its major functions are described in detail in this manual. A very helpful video is also included, but the manual is
The Hoffmann Dovetail Routing Machine model X-20 is designed solely to process material for the Hoffmann Dovetail Joining System. This machine is to be used only to process material for Hoffmann Dovetail Keys, size W-1, W-2 and W-3. USE OF THIS MACHINE FOR ANY OTHER OPERATION IS DANGEROUS AND WILL VOID THE WARRANTY. The manufacturer cannot be
The Hoffmann Dovetail Routing Machine models PP2-TAB and PP2-TAB/4 is designed solely to process material for the Hoffmann Dovetail Joining System. This machine is to be used only to process material for Hoffmann Dovetail Keys, size W-1, W-2 and W-3. USE OF THIS MACHINE FOR ANY OTHER OPERATION IS DANGEROUS AND WILL VOID THE WARRANTY.
The Hoffmann Dovetail Routing Machine model PU2-TL is designed solely to process material for the Hoffmann Dovetail Joining System. This machine is to be used only to process material for Hoffmann Dovetail Keys, size W-1, W-2, W-3 and W-4. USE OF THIS MACHINE FOR ANY OTHER OPERATION IS DANGEROUS AND WILL VOID THE WARRANTY.
The joints samples were composed of a mortise piece (stile) and tenon piece (rail). The first set of joints contained 10 joints made of natural ash wood, while the second set of joints contained 10 joints made of thermo-treated ash wood. The shape and dimensions of the test specimens of joints is shown in Fig. 2. Fig. 2.
Woodstock Intl., Inc. D2796 - 5 - ASSEMBLY The Model D2796 is designed to produce 5 8" half-blind dovetail joints with a router, 7/ 16" O.D. guide bushing (Figure 3), and a 14 , 1/2" dovetail router bit.Two op
