Shop-Made Slot Mortiser Rout ends and edges accurately with this rail-guided jig.

3 By Craig Bentzley Overall dimensions: 18"w × 5 ⁄4"d × 10"h

Some woodworkers hardware to create a simple Build the base discount loose tenons as the rail-guided mortising jig for my 1 As shown in Figure 1, make poor machine-cut cousin of plunge . Despite my initial the base in sections, starting with 3 traditional mortise-and-tenon success, I further improved the the body. From 4"-thick MDF, joinery, but I’ve found the jig by adding Bessey’s auto- cut three pieces ⁄slightly larger joint useful in many instances. adjust toggle clamps. Now my Joining parts using a pair of revised jig is just as reliable Laminate the pieces together, matching mortises and a snug- and accurate as its predecessor, andthan then the finishedtrim an edgedimensions. and end but thanks to the new toggles, to correct an uneven edge and slippage is a thing of the past. slice away any squeeze-out. Now afitting mortise, saves strip, stock. instead And Once set, the auto-adjust trim the uncut edge and end to 1 withof the the sawing proper a tenon setup, to loose fit hold-downs provide the same 2"- 1 tenon joinery is just as strong amount of pressure on a 2 2"- ⁄ 3 as its competition, but quicker thick leg as on a 4" rail without final dimensions. Cut two ⁄ Tip Alert and easier to accomplish. needing to adjust⁄ the footpad. Wanting a slot mortiser but The jig can hold stock up to 8" To prevent MDF from splitting 3 not willing to spend money for wide and 3 4" thick. By adjusting along its edge, clearance and a commercial model, I used the base dimensions,⁄ you can pilot holes before driving screws. leftover material and spare easily mortise still larger parts.

58 woodcraftmagazine.com April/May 2012 Figure 1: Base Exploded View 3 and Base Elevations 2 ⁄8"

9" 5"

1 ⁄4"

1 1 ⁄4-20 × 1 ⁄4" machine screw 1 Attach to router Guide rail: 4 1 3 18" 2 ⁄ " edge guide. ⁄2 × 1 ⁄8 × 10"

1 ⁄2" washer

Stop: 3 1 1 ⁄4 × 1 ⁄4 × 1 ⁄4" 1 ⁄4-20 Outer track: slip nut 1 3 ⁄2 × 1 ⁄8 × 14" 3 ⁄4" , 1 ⁄2" deep 2" screw T-track 1 3 Filler: ⁄2 × ⁄4 × 14" 1 3 ⁄2 × ⁄4 × 14"

1 Inner track: Stop support: 2 3 3 3 3 #6 × ⁄ " pan ⁄4 × 2 ⁄8 × 14" ⁄4 × 1 ⁄4 × 14" head screw

Bottom: 1 1 Body: 1 ⁄2 × 2 ⁄4 × 18" 1 1 2 ⁄4 × 7 ⁄2 × 14"

3" screws

deep dadoes across the front face, Glue the two together, and then 5 Using a hacksaw, cut the attach them to the inner track T-track into three 14"-long 3 2 From 4"-thick MDF, cut with glue and 2" screws. Wipe sections, and attach them to where shown, to fit the T-track. the stop support⁄ and inner away any squeeze-out, especially the assembled base where 1 track. Glue the stop support in the groove for the guide rail. shown, with 2"-long screws. 3 to the body, where shown. Use To make the bottom section, 4" 4 6 ⁄ a piece of T-track to ensure start with two oversized pieces , drill holes, and⁄ attach 3 that the installed track will be of 4"-thick MDF, glue and to theCut topthe T-track,stops from as shown. the stack together, and then a strip of ⁄ 7 Let the glue cure, and then attachflush with the innerthe jig’s track, top edge.again clearance holes where shown, inner tracks to serve as the using T-track to ensure that andtrim then to final attach dimension. with glue Drill and railto fit for within your therouter’s outer edge and 3"-long screws. Make sure that guide. Finally, draw a 1 3 From 2"-thick MDF, cut the the front edge of the bottom centerline across the top the jig’s top edge is flush. ⁄ and front face of the jig. fillerPhotos: Brianand Francis; outer Illustrations: track to Melaniesize. Powell is flush with the jig’s face. April/May 2012 woodcraftmagazine.com 59 Figure 2: Mortising Fences Build the end

1 and hold-downs ⁄4-20 1 End Mortising slip nut 1 Laminate 2"-thick plywood Bessey to make the 1"-thick mortising 3 1 ⁄ 1 × 2 ⁄4 × 3 ⁄2" auto-adjust clamp base toggle clamp fence and clamp bases. Trim the fence and bases to size, 1 1 ⁄4-20 × 1 ⁄4" referring to Figure 2. Lay out machine screw the location for the bolt and 1 #10-24 × 1 ⁄4" screw holes used to secure machine the fence and clamp bases to 1 screw ⁄4-20 four- 5 3 1 arm knob ⁄16 × ⁄8 × 2 ⁄4" the face of the jig. To mark the guide strip screw holes needed to attach 1 ⁄2" the clamps, position the clamps on the 1" plywood, and transfer 1 ⁄4-20 × 1 the hole locations. 1 ⁄2" bolt Using a drill press, drill 1 3 4" and 16" clearance holes 3 3 1 × 2 ⁄4 × 9" End fence ⁄4" washer Washer #10-24 nut ⁄ ⁄ the screw holes so that the headswhere sitmarked. just below Counterbore the Edge Mortising face of the plywood. 5 3 2 Rip two 16 × 8" guide strips, and attach⁄ ⁄ them to the Main fence bottom of the clamp bases. 1 Support 1 ⁄2" (The strips keep the clamps aligned even when the slip 14" 1" nuts aren’t cinched tight.) 3 Attach the auto-adjust clamps to the fence 3 ⁄4 " washer and clamp bases. Build the edge fence 1 3 ⁄4-20 × 8" 7" From 4"-thick plywood, 1 1 1 1 ⁄2" bolt ⁄4-20 four- arm knob cut the main⁄ fence to the size in Figure 3. Lay out a pair of 1 4"-wide slots, as shown. Using a drill press, drill a 2⁄ 1 3" 4"-diameter hole at the top edge⁄ of each slot layout. Next, rout the slots using your router Convenience-PLUS BUYING GUIDE 1 table and a 4"-dia. straight bit. 1. Incra T-Track 48" #142806 $18.99 Rip a strip of 1"-thick 3 ⁄ 1 2. Bessey Auto-Adjust Horizontal Toggle Clamps (3) #152929 $22.50 hardwood to 1 2" wide, and then cut it to 14" long. 1 ⁄ 3. Four-Arm Knob With ⁄4-20 Insert (2) #142230 $3.50 Glue it to the top edge of your 1 5. Sliding T-Nut ⁄4-20 (4) #130440 $1.99 (10) main fence. This strip can Above items are available at Woodcraft stores, woodcraft.com or by calling (800) 225-1153. serve as an edge for clamping Prices subject to change without notice. smaller stock or as a support Hardware: #8 × 2" flathead wood screws (5); #8 × 3" flathead wood screws (3); for a longer board, for instance, 1 1 1 ⁄2" panhead woodscrews (15); ⁄4-20 × 1" panhead machine screws (2); ⁄2" washers 1 1 3 1 1 when mortising the edges (2); ⁄4-20 × 1 ⁄2" bolts (4); ⁄4" washer (2); ⁄4-20 × 1 ⁄4 machine screws (2); 1 3 #10-24 × 1 ⁄4" machine screws (12); ⁄16" washers (12); #10-24 nuts (12) of legs or longer stock.

60 woodcraftmagazine.com April/May 2012 Using the Jig Routing mortises is simple. End Mortising These instructions will ensure consistent results. First, lay out the mortises. Even if you intend to mortise across the center of your stock, always register your layout tools against the outside (show) face of your workpiece. Draw or scribe a line to indicate the center of your mortise. Next, mark a perpendicular line across the center of the width to position the parts on the jig. A

1 appropriate bit (I prefer an Rout the mortise in ⁄4"-deep increments to avoid upcutOutfit spiral), your androuter attach with the an rail overtaxing the router or bit. The trio of auto-adjust hold- to your router’s edge guide. downs offers solid support when routing end grain. To set up the jig for end your , as shown. Edge Mortising Userouting, a clamping first clamp base the to jig to temporarily register the workpiece in the jig, to align the mortise layout with the jig’s centerline. Next, set the mortising fence against the opposite edge, remove the board, and use a to set the fence perpendicular to the top edge of the jig. the fence in place. CinchNow, the clamp knobs the to board secure to the B fence, making sure that the end The edge-mortising fence can support shorter stock, but long parts such as this leg may require additional support. the top of the jig. Slide the clamp basesof the againstworkpiece the is opposite flush with edge edge fence. Set the fence so that Apply glue to the loose tenon, of the work, tighten the locking the top edge of the workpiece slide it into one mortise and screws, and engage the toggles. attach the mating part. Once Adjust your router’s edge Align the centerline on the the glue dries, nobody will guide to center the bit on workpieceis flush with with the thejig’s jig, top and face. know how it was assembled the mortise layout. Set the clamp in place. Lock the stops because no one will be stops on the top of the jig to in their appropriate positions, able to pull it apart. n match the mortise length. and rout the mortise (Photo B). To rout, plunge the router To make your tenons, plane to full depth at each end of the Tip Alert mortise (Photo A rip to width, and then round the To ensure that the mortises line up, work from end to end, edgeshardwood with stock a round-over to fit the bit slot, or up, always clamp the “show” 1 plunging in 4" increments.). To finish face of your parts against the 1 For making⁄ edge mortises, the tenon stock 16" shorter than face of the jig. file to fit the mortise. Crosscut replace the end fence with the needed to allow ⁄room for glue. April/May 2012 woodcraftmagazine.com 61