WoodPlans Online - Mortise & Tenon Joints

http://www.woodonline.com

DOWNLOADABLE

®

of 14DS-032 ©Copyright Meredith Corporation 1997, 2003

Mortise &Tenon Joints

If you’ve shied awayfrom mortise-and-tenon joinerybecause it soundstoo complicated,take heart. With ourtenoning jig and alittle practice, youcan turn out tight-fit-ting joints like a pro-fessional craftsman.

Editor’s Note:

According to woodworking

tradition, you cut a mortise

first and fit the tenon to it. The

technique yields tight-fitting

joints, but requires painstak-

ing trial-and-error trimming.

Determined to find an easier

way, we developed a new

tenoning jig, detailed on page

8, and a technique that stands

tradition on its head.

Our jig guarantees your success

TENON

Cursor seton 1"

ANATOMY OF A MORTISE-AND-TENON JOINT

Tenon thickness(1/2 to 1/3 thethickness ofthe stock)

Tenon setback(typically at least

1/4"or the widthof the shoulder)

Tenon length(typically 2/3 the widthof the stock containingthe mortise)

Chamfer the tenon's endslightly to ease insertioninto the mortise.

Cheek

Shoulder width(1/4 to 1/3 the thickness of the stock)Mortise depth

(1/16" deeper than thelength of the tenon)

Mortise width(equals thethickness

of the tenon)MORTISE

Mortise length(equals the width

of the tenon)

End

Side

Shoulder

3

2

1

Cursor set on1 + 1/4" for a 1/4"shoulder width

1/4" shoulderwidth

Blade height set for tenonlength less 1/16"

STEP 1Adjust the face of workpiecesupport flush with blade.

STEP 2Setting the rule

3

2

1

ADJUST YOUR JIG FOR PRECISION CUTS

TM

of 14

TM

of 14

What makes amortise-and-tenonjoint so strong?Check out the construction of asturdy chair or table sometime,and you’ll probably find that itwas built with mortise-and-tenon joints. When it comes tostrength, few woodworkingjoints match the mortise-and-tenon. That’s why this oldstandby shows up so often inleg-and-rail construction andother adaptations that subject ajoint to stress from severaldirections at the same time.Study the typical mortise-and-

tenon joint shown in theAnatomy of a Mortise-and-Tenon Joint drawing on page2, and you’ll notice that thelargest mating surfaces containface grain. When glued togeth-er, these face-grain-to-face-grain areas create exceptionallystrong bonds. This gives thejoint much greater strengththan a butt joint, in which oneof the mating surfaces containsonly end grain. Proper propor-tions keep both the tenon andmortise strong.

How to build andadjust the “On-the-Money Tenoning Jig”As mentioned in the Editor’sNote, our tenoning jig is the keyto cutting professional-lookingjoints. So turn to page 8, andbuild the jig. When you’vecompleted it, return here andread on.To adjust your jig for preci-

sion cuts, start by placing thetenoning jig on your tablesaw,with the bar in the miter-gaugeslot. Loosen the knob on thesliding table, and position it sothe fence clears the saw blade.Raise the blade to 1", and thenmove the sliding table so theface of the fence aligns flushwith the outside edge of theblade, as shown in the AdjustYour Jig for Precision Cuts

drawing, page 2. Tighten theknob to hold the sliding tablein place.With the blade properly alignedwith the fence, slide the jig’sbuilt-in steel rule until the cur-sor lines up directly over the 1"mark, as shown in Step 2.(Using the 1" mark providesmore accuracy than trying toalign the mark on the “zero” endof the rule.)Now, loosen the knob on the

sliding table, and adjust the cur-sor along the rule to make thedesired shoulder width, asshown in the drawing on page2. Our example shows the set-ting for a ‹" cut, but for otherwidths, adjust the cursor theappropriate distance from the 1"mark on the scale.

How to make flush mortise-and-tenonjointsWhen we developed the “On-the-Money Tenoning Jig,” wealso were looking for a simplerway to create tight-fitting mor-tise-and-tenon joints. Ratherthan the traditional method ofcutting the mortise first and fit-ting the tenon to it, we decidedto use the precision-cut tenonsproduced with the tenoning jigto accurately lay out the match-ing mortises.

Our technique, described here,uses a guide-block to aid inboth the mortise layout andcutting processes. Cut usingthe same jig settings as thetenon, the guide-block ensuresaccurate placement of the mor-tise. It also keeps your chiselaligned vertically when yousquare up the mortise.Note: Before you start cutting,choose and mark the best side ofyour workpieces. Use these ref-erence marks when laying outyour mortises and tenons so thebest sides get the exposure.

Tips on tackling the tenonBegin by laying out the tenon asshown in the Laying Out aTenon drawing, above. A com-bination square and a sharp pen-cil or scratch awl work great fortransferring marks to all foursides. For our sample project,we made the tenon 1" long, withfi" setbacks and ‹" shoulders.Next, cut the shoulders. Using amiter gauge with an auxiliaryfence, align the shoulder of thetenon with the saw blade. Attacha stopblock to the auxiliaryfence to duplicate the cuts.Lay the workpiece flat on the

saw table, and adjust the heightof the blade so it just touches themarked edge of the tenon cheek.

Front

Shouldersetback

Shoulder width

LAYING OUT A TENON

Adjust the saw blade depth, and use a miter gaugewith an auxiliary fence and a stopblock to cut thetenon shoulders in the workpiece and one side ofthe guide block.

TM

of 14

12"

STEP 2 Make the cheek cut.

STEP 1Make theshoulder cut.

STEP 3Cut the guideblock to length.

2"

Length ofthe tenon

Shoulder widthof tenon

Guideblock madeusing same settingsas tenon

GUIDEBLOCK

2"

Cut the shoulders on both sidesof the tenon, as shown inPhoto A. Using a 12"-longpiece of scrapwood the samethickness and width as yourworkpiece, make a shoulder cutin one side only (see theGuideblock drawing. Set thispiece aside for the guideblock.Align the tenon end with thestopblock, and cut the two set-back shoulders as shown inPhoto B. And now for the tenon cheeks.With the tenoning jig set for a‹"-wide cut, raise the blade toÍ". Secure the workpiece asshown in Photo C, turn on thetablesaw, and push the work-piece through the blade. Rotatethe workpiece 180°, clamp itdown, and cut the secondcheek. Without changing thejig setup, make one cheek cutin the guide-block piece, andthen set it aside. Finish up with the tenon set-

backs. Set the jig to make a fi"-wide cut, clamp the workpiecein the jig as shown in Photo D,and cut the setback. Rotate theworkpiece 180°, and cut thesecond tenon setback.

A B

Turn the workpiece on edge, butt it against the stop-block, and cut the tenon setback shoulder. Rotatethe piece 180° and cut the other setback shoulder.

TM

of 14

Finally, crosscut the scrap-wood guide block to finishedlength, making it 2" longerthan the length of the tenon cut(see the Guideblock drawing,on page 4).

Now for the matching mortiseTo lay out the mortise, positionthe guideblock on the piece tobe mortised, and then mark the

side of the mortise, as shown inPhoto E. Then, place theguideblock on the other side ofthe workpiece, and mark theopposite mortise side.

Using the tenon as a guide,mark the proper length of themortise as shown in Photo F.Be sure to keep the edge of thetenoned board flush with theend of the mortise piece.

To rough out the mortise,

C

With the jig cursor set at 1‹" (for a ‹" cut), clampthe board against the jig fence, and cut the tenoncheeks in your workpiece and in the one side of theguide block.

D

Adjust the jig to the proper setback, clamp the work-piece against the jig’s dadoed end, and cut the tenonsetbacks.

E

Hold the guideblock firmly on the piece to be mor-tised, and mark the location of the mortise sideswith a sharp pencil.

F

Position the tenon atop the piece to be mortised,and mark the mortise ends. Be sure to keep the twoworkpieces flush and square.

clamp the workpiece in a drillpress, and using a brad-point bit„" smaller in diameter than thewidth of the mortise, drill a seriesof holes the length of the mortise,as shown in Photo G. The holesshould just touch or have a smallgap between them to avoid drillbit deflection and poor align-ment. The holes should be 1„"deep, or „" deeper than thelength of the tenon.

TM

of 14

G

Using a bit „" smaller than the mortise width, drilla series of holes the length of the mortise. Drill theend holes first and make all holes „" deeper thanthe length of the tenon.

H

Clamp the guide block to the workpiece. Keep theflat side of a wide chisel held firmly against theblock, and shear the excess wood from the sides ofthe mortise.

I

Sand slight chamfers on the end of the tenon to make it easier toinsert the tenon in the mortise. Dry-fit the mating joint pieces andsand the tenon faces or chisel the mortise as necessary.

To square-up the mortise,clamp the guideblock in posi-tion on the mortised piece, andhold your chisel flat against theblock, as shown in Photo H.The guideblock keeps the chis-el vertical as you shear awaythe waste from the sides of themortise. Use a chisel the samewidth as the mortise to squareup the ends.

Final fitting, gluing,and cleanupBefore you try fitting the jointtogether, sand slight chamferson the end of the tenon, asshown in Photo I. This lets youfit the tenon into the mortisemore easily.

Test-fit the mating work-pieces before applying glue,and sand the tenon or chiselthe mortise as necessary.Apply glue to all faces of bothsides of the joint as well as thetenon shoulders, and thenclamp the workpieces togeth-er. Use a putty knife or chiselto scrape off any glue squeeze-out after a tough skin forms. Despite the jig’s accuracy, the

faces of the mating pieces may

not always align perfectly flush.To get them flush, we prefer touse a random-orbit sander toavoid cross-grain scratches.

Variations foradded strengthThe flush joint we just showedyou works well in many applica-tions, but you can make the jointeven stronger. By adjusting thetenon's placement, you can

strengthen the correspondingmortise. These adaptations workwell in leg-rail construction.By shifting the tenon setback

(see the Increasing TheSetback To Minimize EndGrain Breakout drawing onpage 7), you cut the mortisefarther away from the end ofthe leg, reducing the chancefor endgrain breakout.

Tenon setbackincreased

Chance of end grainbreakout reduced

INCREASE THESETBACK TO

MINIMIZEEND GRAINBREAKOUT

End grainbreakout likely

Tenonsetbacksequal

Tenoncentered

OFFSET THE TENON FOR ASTRONGER MORTISE

Tenonoffset

Mortise cheekstronger

Mortise cheektoo thin

Saw kerf

TRADITIONALVARIATIONS

Dowel

Thin wedge

Pinned tenon

Wedged through tenon

RAIL

LEG

RAIL

LEG

TM

of 14

In some situations, the rail fitsflush with the front face of theleg. If the tenon were centered,the outside mortise wall wouldbe thin and weak. But by off-setting the tenon, you can keepthe rail flush with the leg with-out weakening the tenon or themortise wall. (See the OffsetThe Tenon For A StrongerMortis drawing.)

Early craftsmen used a varietyof methods to reinforce mortise-and-tenon joints. While today’sglues will hold joints tight,

using pins or wedges, as illus-trated in the TradionalVariations drawing, still bol-sters strength while lending anold-world touch to your project.

To pin a tenon, first assemblethe mortise-and-tenon joint.When the glue dries, drill a cen-tered hole completely throughthe joint. Apply glue to thedowel, tap it into place, saw offthe excess, and sand it flush.

In a through-tenon joint, thetenon extends completelythrough the mortised work-

piece. A wedge driven into theend of the tenon effectivelylocks it in place. To wedge athrough tenon, cut a saw kerfinto the end of the tenon, aboutthree-quarters of its length.Glue and assemble the joint,and then apply glue to a thinwedge and drive the wedge intothe saw kerf. When the gluedries, saw off the excess tenonand sand it flush.¿

Metal rule attaches to jig with magnets;it is used to measure shoulderwidths of tenon.

Knob secures and allowsadjustment of slidingtable and fence.

SLIDING TABLE

BASE

FENCE

Adjusts to accommodate 1" shoulder cuts

Rabbet allows blade to be alignedwith the face of the fence.

Right-angle fence provides a clampingsurface and support for all fourfaces of the piece being machined.

TM

of 14

Tenoning JigBuild it in just an evening or two for a lifetime of accurate results

Hopefully, the seminarhas excited you about the“strengths” of mortise-and-tenon joinery. And,this easy-to-make table-saw jig is the accessorythat makes it all possible.

Let’s start withthe base andsliding tableNote: See the Buying Guide forour source of hardware andBaltic birch plywood. 1 Cut two pieces of ‡" ply-wood for the base (A) and twopieces for the sliding table (B)to the sizes listed in the Bill of

Materials, plus fi" in length andwidth. (Due to its stability andstrength, we used ‡" [18mmactual] Baltic birch plywood.)2 With the edges and endsflush, glue and clamp the twobase pieces together face-to-face. Repeat with the tworemaining pieces to form thesliding table. Later, remove theclamps and cut the base (A) andsliding table (B) to the finishedsizes listed in the Bill ofMaterials.3 Measure the exact width ofthe miter-gauge groove in yourtablesaw. Cut the base guide bar(C) to size. Use solid maple orbirch if you’re using your stock,

or, if you use our hardware kit,cut the UHMW (ultra-high mol-ecular weight) polyethylene tosize. (We found polyethyleneslides easier in the groove thanwood. Plus, polyethylene willnot change in size with seasonalchanges in humidity.) The guideshould slide in the groove with-out slop. Set it aside; you’ll addit later.4 Using a dado head in yourtablesaw, cut a dado the widthof your guide bar (C) and ¤"deep on the bottom side of thebase (A) where dimensioned onthe Exploded View and PartsView drawings. The guide bar(C) will fit into this dado later.

#8 x 11/2" F.H.wood screws

A

1

2

3

4

5

1

2

3

4

5

7/16" slot 313/16" long

3/8" flat washer

13/4"

C

#8 x 3/4"F.H. wood screw

3/8" hole with a7/8" counterbore

1/2" deep on bottom

1/2" magnet1/4" thick

1/2" hole1/4" deep3/4" dado

1/16" deep

6" metal rule

EXPLODED VIEW

7/64" pilot hole3/4" deep

#8 x 3/4" F.H.wood screws

F

G

H

#8 x 11/2"F.H. wood screws

5/32" shank hole,countersunk 2" radius

2" radius

7/64" pilot hole3/4" deep

11/2" rabbet1/8" deep

E

CURSOR

3/4" dado1/8" deep

11/2"

11/2"

1"

*3/4" dado 1/4" deep*Cut dado to width to match exact thickness of plywood.

9"

1"

B

3/8" carriage bolt3" long, epoxied in

place in base

D

10"

10"

10"

SLIDINGTABLE

BASE

5/32" shankhole,

countersunk

3/4" dado3/16" deep

Cursor recess

3/8-16 3-prong13/4"-diameter knob

A

**3/4" dado 1/8" deep

** Equal to the width of your miter-gauge guide bar.

AB

Equal tocombinedthicknessofand .

Bottom edge ofmust be flush withor slightly above thebottom edge of .

H

B

TM

of 14

TM

of 14

PA

RT

S V

IEW

10"

9"

3 /4"

45/8

"

1 /2"

15/8

"33

/8" 31

3 /16

"

11/1

6"

3 /4"

dad

o3 /

16"

deep

on b

otto

m s

ide

7 /16

" sl

ot 3

13/1

6" lo

ng

SLI

DIN

G T

AB

LE

57/8

"

B**

3 /4"

dad

o

1 /8"

dee

p

on b

otto

m s

ide

10"

10"

13/4

"**

3 /4"

45/8

"

3 /4"

57/8

"

5"3 /

8" h

ole

with

a7 /

8" c

ount

erbo

re1 /

2" d

eep

on b

otto

m

1 /4"

11/4

"21

/2"

21/2

"21

/2"

11/4

"

3 /4"

dad

o1 /

8" d

eep

3 /4"

dad

o1 /

16"

deep

1 /2"

hol

e1 /

4" d

eep

BA

SE

**E

qual

to th

e w

idth

of

you

r m

iter-

gaug

e

guid

e ba

r.

A

3 /4"

3 /4"

dad

o 1 /

4" d

eep

on in

side

face

.C

ut d

ado

wid

th to

mat

ch e

xact

thic

knes

s of

ply

woo

d.

33/4

"3 /

4"

5 /32

" sh

ank

hole

,co

unte

rsun

k

25/8

"

41/8

"

41/2

"

10"

11/2

"

11/2

"

3 /4"

H

1"4"

5 /32

" sh

ank

hole

,co

unte

rsun

k

DC

4"A

3 /4

x 24

x 4

8" B

irch

plyw

ood

CU

TT

ING

DIA

GR

AM

1 /2

x 31

/2 x

12"

Map

le

*Pla

ne o

r re

saw

toth

ickn

ess

liste

d in

the

Bill

of M

ater

ials

.

**

AB

B

D

EF

GH

C

TM

of 14

Bill of Materials

A* base 1fi" 10" 10" LBP 1

B* slidingtable 1fi" 9" 10" LBP 1

C guidebar Á" ‡" 11" M 1

D guidebar ˇ" ‡" 10" M 1

E* horz.support ‡" 3‡" 8‹" BP 1

F fence ‡" 6" 9‹" BP 1

G radiusedend ‡" 3" 3 ‡" BP 1

H dadoedend ‡" 4fi" 10" BP 1

* Initially cut parts oversized. Trim to finished sizeaccording to the how-to instructions.

Materials Key: LBP–laminated Baltic birch ply-wood, BP–Baltic birch plywood, M–maple.

Supplies: #8×‡" flathead wood screws (7),#8×1fi" flathead wood screws (15), fi" magnets‹" thick (4), 6" metal rule, ›" carriage bolt 3" longwith mating washer and plastic knob, ¤×4×4"acrylic for cursor, UHMW polyethylene for theguide bar (C), epoxy, clear finish.

Finished SizePart M

atl.

Qty

.

WT L

5 Cut a ‡" dado ¤" deep on the topside of the base (A) and a mating ‡"dado ‰" deep on the bottom side ofthe sliding table (B), where shown onthe Parts View drawing. Later, you’llscrew the guide bar (D) into the dadoin the top of the base. And whenassembled, the sliding table (B) willslide on the top, exposed portion ofthis guide bar.6 Cut a ‡" dado „" deep in the top ofthe base (A) to house the 6" metal rule.(See the Buying Guide for our sourceof the rule.)7 Cut the second guide bar (D) so it fitssnugly in the top dado in the base, andslides smoothly in the ‡" dado on thebottom of the sliding table. Set thisguide aside also.8 Mark the centerpoints, where dimen-sioned on the Parts View drawing, anddrill the holes for the magnets in thedado in the top of the base (A).Measure your magnets before drilling,they may vary in size. You want themagnets to sit just a hair below the sur-face of the dado. 9 Mark the centerpoint, and drill a Œ"hole fi" deep on the bottom side of thebase (A). Then, drill a ›" hole centeredin the Œ" hole and through the base forthe ›" carriage bolt. Check the fit tomake sure the bottom of the carriagebolt doesn’t protrude.10 Mark a pair of centerpoints, drill aÁ" hole at each point, and cut betweenthe holes with a scrollsaw or jigsaw toform the Á"-wide slot in the slidingtable (B), where dimensioned on theParts View drawing. 11 Drill countersunk mounting holesin the guides (C, D), where dimen-sioned on the Parts View drawing.Screw the guides in place, making surethe screw heads don’t protrude.

TM

of 14

Drag the blade of an X-acto knife sideways to scribe the centerlineand cutlines on the acrylic cursor blank.

Bit centerpoint

Use Œ" Forstner bitto score the outsidediameter.

Score a line alignedwith the hole centerpoint.

Score lines flushwith outside edgesof the Œ" circle.

4"

4"

FORMING THE CURSOR

¤" acrylic

Form the cursor next1 Cut a piece of ¤" clear acrylicto 4×4". Chuck a Œ" Forstner bitinto your drill press, and positionthe bit over the acrylic, roughlywhere shown on the FormingThe Cursor drawing. Clamp theacrylic securely to your drill-press table.2 Start the drill press, and slow-ly lower the bit until the outsideedge and centerpoint of the bitjust barely scores the acrylic.3 Using a small square and anX-acto knife held sideways (itscores better this way), scorethe three lines on the bottomside of the acrylic, where shownon the drawing left and inPhoto J.4 To make the centerline on thecursor more visible, use a felt-tipped marker to highlight themiddle scribed line. Wipe anyexcess marker off the surface ofthe cursor.5 Using your bandsaw fittedwith a ¤" blade or a scrollsawwith a #10 blade, cut the cursorto shape. Sand the edgessmooth.6 Working from the bottomside of the cursor, drill a ¸"countersunk shank hole cen-tered over the bit centerpointwhere shown on the CursorFull-Sized Pattern on page 13.7 Using the Cursor Locationdrawing for reference, form thecursor recess on the bottom sideof the sliding table (B).

Add the workpiece supportNote: Plywoods vary in thick-ness. All dimensions are basedon plywood measuring exactly‡" thick. See the tinted boxeson the Exploded View drawingon page 9 before locating thehorizontal support (E) againstthe fence (F).1 Cut the horizontal support (E)to size plus fi" in length. Then,cut the fence (F), radiused end(G), and dadoed end (H) to size.

J

TM

of 14

Scribe acenterlineon bottom

side.

¸" shank hole,countersunkon bottom

side

CURSORFULL-SIZED PATTERN

Œ"

1Œ"

B

313/16"

7/8"11/16"

7/8" hole5/32" deep

#8 x 3/4"F.H. wood screw

CURSOR

CURSOR LOCATION(viewed from bottom side)

Centerline

Bore a 7/8" hole5/32" deep.Complete cursorrecess with asharp chisel.

STEP 1

STEP 2

Use a strip of wood, a pair of clamps, and waxed paper to hold the magnets in place until the epoxy cures.

K

TM

of 14

The purchase of these plans does not transferany copyright or other ownership interest in theplans, the design, or the finished project to thebuyer. Buyer may neither reproduce the plansfor sale nor offer for sale any copies of the fin-ished project.

Produced by Marlen KemmetWritten by Marlen KemmetProject design: James R. DowningGraphic Design: Jamie DowningIllustrations: Kim Downing; Lorna JohnsonPhotograph: John Hetherington©Copyright Meredith Corporation 1995, 2003

Buying GuideHardware kit. All the hardwarelisted in the Supplies listing atthe end of the Bill of Materialsexcept for the finish and epoxy.WOOD KIT™ TENJ1, $27.95plus $3.75 shipping. Schlabaughand Sons Woodworking, 72014th Street, Kalona, IA 52247 orcall 800/346-9663 to order.

Hardware and precut woodkit. All the pieces listed in thehardware kit, plus all the Balticbirch plywood and maple pieceslisted in the Bill of Materials cutto size and shape (but notpredrilled). WOOD KIT TENJ2,$94.50 plus $12 shipping.Address and phone at left.

2 Cut the rabbet along the out-side face of the fence (F) whereshown on the Exploded Viewdrawing.3 Cut a ‹"-deep dado in theinside face of the dadoed end(H) to the same exact thicknessas your plywood.4 Mark the centerpoints, anddrill holes in the dadoed end(H) where dimensioned on theParts View drawing. Clampthe dodoed end (H) to thefence (F), and drive in thescrews. Drill the holes, andscrew the opposite end (G) tothe fence. Measure the dis-tance between the ends (G,H), and cut the horizontalsupport (E) to final length andscrew it in place, making sureparts G and H meet at rightangles to part E.5 Clamp the support (E, F, G,H) to the sliding table (B), andscrew the two assembliestogether, keeping the outsideface of F square to the slidingtable.

Finishing and final assembly1 Finish-sand all the pieces andseal with polyurethane.2 Cut a piece of wood to‡×Ø×12". Then, put a drop ofepoxy in each magnet hole, fitthe magnets into the holes, andwipe off any excess epoxy. Asshown in Photo K on page 12,position the strip of wood overthe magnets, and use it as aclamping bar to hold the mag-nets in place until the epoxycures. Later, remove the clamp-ing block and clamps.3 Screw the acrylic cursor inplace in the recess on the bot-tom of the sliding table (B).4 Position the sliding table (B)on the base (A). Slide a ›" car-riage bolt through the ›" holein the base (A) and through theÁ" slot in the sliding table (B).Slide the two assemblies back

and forth to check the fit, andthen epoxy the carriage bolt inplace. Attach a washer and plas-tic knob onto the bolt, whereshown on the Exploded Viewdrawing. To prevent the jigfrom possibly rocking on thesaw table, make sure that thebottom edge of the fence (F) isflush with the bottom surface ofthe base (A). If the fence (F) ishigher, you may encounter a bitof rocking when the slidingtable/fence is slid away fromthe base when cutting tenons.This can result in poorly cuttenons.5 Lay the metal 6" rule in placeon the magnets in the shallowdado. ¿

WoodPlans Online - Mortise & Tenon Joints

Documents

Transcript of WoodPlans Online - Mortise & Tenon Joints