fast and easy Finger Joints You can start and finish building a box in one day — without any special .

Finger joints always remind me of FINGER JOINT positioned so the distance between two hands clasped together. A set of To build a box with finger joints, a it and the blade is identical to the “fingers” on one piece fits between series of kerfs are cut with the table width of the key itself. the “fingers” on the other. But what . And the pieces are supported To add the key, I clamped the provides the “muscle” here is glue. and positioned with the help of a jig to the miter and cut a These interlocking fingers create a — basically, just an auxiliary fence notch in it (Step 1 on the next page). lot of edge-to-edge surface area for with a key to index the fingers. Then I cut the key from a scrap piece a really strong glue joint — which, Fence & Ledge. My auxiliary to fit tight into this notch (Step 2). A in turn, makes for a solid box. fence is a piece of stock temporar- tight fit here is critical — you don’t While cutting all those tiny fin- ily clamped to the miter gauge want any “play” when fitting the gers might seem tedious, it’s really (drawing below). But I also add a kerfs of the workpiece over the key. 1 a snap. All you need is a jig that ⁄4"-thick ledge under Setting Up the Jig. With the key you can build in about fifteen min- this fence. This way, the workpiece glued in place, the jig can now be utes with a few shop scraps. doesn’t ride directly on the table set up. There are two things to do Plus, you don’t need a shop full (and over the blade insert that may here: position the key by adjusting of tools. To make the fingers, I use not be flat and level). Instead, the the fence on the miter gauge and a outfitted with a miter piece rests securely on the ledge. raise the blade to the right height. gauge and a rip blade (or any blade Key. While the fence and ledge Adjusting the Fence. When set- that cuts a flat-bottomed kerf). support the workpiece, a small key ting up the fence, the distance of the added to the fence is really what key from the blade has to match the makes the jig work. It’s cut to match thickness of the blade (and the key). NOTE: AFTER THE JIG IS SET UP AND THE ADJUSTMENTS ARE the width of the kerf left by your Otherwise, the fit of the fingers will MADE, SCREW FENCE TO MITER GAUGE saw blade. And this key is either be too tight or loose, see the box on the next page. AUXILIARY I start by positioning the key FENCE KEY with a second, identical key (Step 3). Then I check the setup by cutting LEDGE (!/4" Hdbd.) a series of finger joints on two test pieces, as you can see in Step 4. RIP BLADE But I don’t just use any scraps that happen to be lying around. Instead, I make the test pieces MITER GAUGE identical to the final workpieces AUXILIARY TOP VIEW FENCE in width and thickness (but not necessarily length). I even use the same type of . This way, I can use these test pieces later when KEY LEDGE plugging the holes left by the grooves for the bottom.

ShopNotes No. 110 Page 1 of 4 ©2010 August Home Publishing. All rights reserved. Using a second key to set the first will get you close. But you’ll prob- Jig Setup: Step-by-Step ably still need to “tweak” the fence one way or the other, see box and WIDTH OF KEY tip in margin at right. It’s impor- MUST FIT tant to be patient; it will probably TIGHT IN NOTCH take several adjustments (and test cuts) before the fit is perfect. I like to end up with a snug fit NOTE: SET WORKPIECE so that when dry assembling the ON LEDGE pieces, I have to work the pieces a KEY bit to press the fingers together and pull them apart. This way, I avoid After setting the blade slightly below Next, size a key that will fit tight in using clamps when gluing the 1 the thickness of the stock, cut a 2 the notch that was just cut in the boxes together. More on that later. notch in the fence (and ledge). fence. Then glue it in place. Setting the Blade. After the key is set and the fence has been clamped { When setting up to the miter gauge, I set the height a finger joint jig, of the saw blade. Of course, when TEST make any micro- you’re done, you want the fingers PIECES adjustments perfectly flush with the mating “visible” by draw- pieces. But here, when setting the FOR INITIAL SETUP ing a line across USE SECOND KEY blade, I let the fingers protrude just the jig and table. 1 slightly — less that ⁄64". (I’ll sand them flush later.) To set the blade height, I position Now using a spacer the same size Test the setup and make needed the workpiece on the ledge next 3 as the key, move the fence so the 4 adjustments to fence and blade. to the blade. But I start with the spacer fits between the key and blade. Then fence to miter gauge. blade slightly below the height of the workpiece and sneak up on the Building a Box need to make is to raise or lower final height as I test the fit, see box With the jig set up, the hard part the blade to accommodate different below. This way, the auxiliary fence is over, and the fun really begins. thicknesses of stock. will back up the cut completely, and With this simple jig, you can build Wide Pieces. When building a there will be less chance for chipout any number of boxes quickly. Plus, box, I start with all four sides of the when cutting the fingers. about the only adjustment you’ll box planed to finished thickness Fine Adjustments

IF THE FIT IS TOO TIGHT OR TOO LOOSE, ADJUST FENCE

TOO FENCE TOO LOOSE TIGHT

KEY

LEDGE Loose fit. If there’s a gap be- Tight fit. If the fingers won’t fit tween each finger, slide the key into the slots at all, slide the key and fence away from the blade. and fence towards the blade.

KEY

TOO SHORT

IF FINGERS BLADE ARE TOO LONG OR TOO SHORT, Short fingers. If the blade is set ADJUST BLADE Long fingers. If the fingers ex- too low, the fingers will be short, tend too far, the saw blade is too TOO LONG so raise the saw blade slightly. high and needs to be lowered.

ShopNotes No. 110 Page 2 of 4 ©2010 August Home Publishing. All rights reserved. and cut to final length. But I leave WASTE END them slightly oversized in width. I SIDE don’t worry about the final height (width) until after the fingers are cut. To see what I mean, take a BOTTOM look at Step 10 below. PANEL Label Pieces. With the pieces ready, the next step is to label END MARK PIECE them all, as you can see in the BOTTOM drawing at right. I first mark the EDGE bottom edge of each piece with SIDE PIECE an ‘X’ as the good edge I use to ref- LABEL a. erence my cuts. I also number the CORNERS corners to keep them together as TO ADD the fingers are cut. NOTE: PIECES BOTTOM CUT TO LENGTH, SEE STEPS Cutting the Joints. With the jig BUT ARE SLIGHTLY 11 AND 12 OVERSIZED IN HEIGHT to guide you, cutting finger joints BOTTOM is just about automatic. But you do be as consistent as possible. Steps things that need to keep some things in mind. 6 though 9 do a good job of show- will help. I found that it’s good to be extra ing this. Even shifting the pressure First, make sure your blade is sharp. careful with the very first slot that’s slightly can affect the final fit. So I Second, make sure the notch in the cut in each piece, as in Step 5. Check hold the piece against the jig with jig matches the height of the slots that there’s nothing on the jig (like both hands and try to make each you’re cutting. This way, the work- ) to throw off this cut — pass exactly the same. piece is backed up completely. the piece should rest squarely on Chipout. I should also mention Final Height. After the fingers the ledge and against the key. something about chipout. Chipout are cut, I simply trim the top edge Then, when cutting the rest of can be a problem any time you of the pieces so there’s a full finger the fingers and slots, you need to cut finger joints, but there are two (and slot) left, as you see in Step 10. Finger Joints: Step-by-Step

KEY

BOTTOM BOTTOM OF PIECE OF PIECE

To begin, set the bottom edge of Now, straddle the first slot over the Next, flip the piece end-for-end, 5 the piece against the key and hold 6 key and cut a second slot. Repeat 7 keeping the bottom edge against it tight as you pass it over the blade. this process across the piece. the key. Then cut the slots on this end.

TRIM WASTE FROM TOP BUTT EDGES BOTTOM EDGES TOGETHER

Now, rotate the piece so the first To cut the next slot, slide the slot After all four corners are com- 8 slot straddles the key. Set the mat- 9 just cut up tight against the key. 10 plete, trim the top edge of each ing piece in place and cut its first slot. Then continue as before. piece to leave a full finger or slot.

ShopNotes No. 110 Page 3 of 4 ©2010 August Home Publishing. All rights reserved. Bottom Panel. With all the when it’s time to apply the glue, is seated, there’s enough pieces cut to size, the next step is to there’s really no time to dawdle. friction to hold the corner cut the grooves for a rabbeted bot- You have to get glue in all the fin- together, so I don’t even have tom panel (Steps 11 and 12). The gers and get the joints together to use any clamps. 1 bottom is made from ⁄4" . before the glue sets up. Adding Clamps. However, once Cutting a in each edge of the To help, I apply glue to the ends in a while, I’ll have a cupped piece panel forms a tongue that fits in the of the pieces, see margin photo that needs to be clamped (Step 14). grooves cut in the box pieces, refer below right. And I use a slow set- In this case, I apply the clamps just to drawing of the box on page 3. ting glue, like white glue or liquid inside the fingers and add a small To cut the grooves for the panel, hide glue. Of the two, I prefer hide spacer in the middle to keep the I use the same saw blade and set glue because it cleans up well with sides of the box from bowing in. the rip fence so that the is water and if any glue is left on the Plugs. When the glue is dry, there aligned with the first finger on one inside corners, it doesn’t stand out are still a couple “clean-up” steps. of the box sides, as you can see in much after an oil finish is applied. First, I plug the holes left by the Step 11 below. Then double-check And speaking of glue on the grooves for the box bottom (Step the setup with the end piece. inside corners, I scrape it out and 15). Then I trim them and sand the Assembly. When the bottom is wipe off as much as possible with a sides of the box smooth. cut and rabbeted to fit the grooves damp rag before it sets up. It’s just Flatten Bottom. Finally, you may (Step 12), I dry-assemble the box. too hard to remove after it’s dried. notice the corners of the bottom of Then when satisfied with the fit, Seating the Joint. Once the glue the box aren’t perfectly flush. But it’s time to glue it together (Steps is applied, I drive the fingers into this is an easy fix. Just attach adhe- 13 through 16). the slots using a and one sive-backed to a flat Glue. Dry assembling a box can of the test pieces that I made ear- surface and sand the bottom of the be done at a leisurely pace, but lier (Step 13). Often once the joint box lightly (Step 16). Assembling the Box: Step-by-Step

NOTE: SIZE RIP FENCE BOTTOM TONGUE TO MALLET EDGE FIT GROOVES !/4

AUXILIARY SCRAP FENCE BOTTOM PANEL TEST NOTE: PIECE ALIGN BLADE TEST FIT WITH FIRST FINGER !/8 BEFORE APPLYING GLUE

Next, to hold a bottom panel, cut With the bottom panel cut to To seat the joints after applying { To assemble a 11 a groove on each piece, using a 12 size, rabbet its bottom edges 13 glue (see margin), use a mallet finger joint quickly, workpiece to set the fence. to create a tongue to fit the grooves. and one of the test pieces. simply run the glue across the ends of the fingers so it runs into the slots.

GROOVE

SCRAP PIECE PREVENTS - BOWING BOTTOM BACKED PANEL SANDPAPER

Apply clamps to the corners, if With the glue dry, plug the If necessary, apply adhesive- 14 necessary. A spacer will keep 15 exposed grooves at the bottom 16 backed sandpaper to a flat the sides from bowing in. of the box and trim them flush. surface and sand the bottom flat.

ShopNotes No. 110 Online Extras Page 4 of 4 ©2010 August Home Publishing. All rights reserved.