| Sitting Bench -- Legs, Joinery and Accents |
From "Wood Works"
episode WWK-108 |
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With the raw wood slabs cut and milled, work begins on shaping the pieces and creating the joinery. Mortise-and-tenon joinery is used to hold the bench seat and legs together. Materials: Milled maple stock
Curved-profile templates for cutting and shaping seat
Band saw
Jointer
Handheld router
Table saw with fence
Disc-sander and jig
Air-powered die-grinder and ball-mill bit
Carpenter's square
Straightedge
Tape measure
Carpenter's pencil
Saftety glasses or goggles
Note: Cut sizes may vary. For exact measurements, please contact David Marks through his website -- information below under Resources. Safety Alert: Always wear safety goggles or safety glasses when working with wood, saws, drills, routers, etc. Cutting the Legs and Seat;
Making the Joinery Steps: - Two curved templates are used for shaping the bench seat. One has a curved profile that will be used for shaping the top surface of the seat. The other provides the shape of the bottom -- which is angled on either side but flat across the mid-portion of the bottom (figure A).
- The cuts on the bottom creates a wedge shape on each end. The two angles on the bottom surface will set the legs at an angle once they are installed -- contributing to the Asian-styled aesthetic of the design. The cuts also establish a 90-degree corner between the leg and the bottom of the seat (figure B), which makes for a stable structure and simplifies the joinery process.
- The band saw is used to cut away the wedges that were marked on the bottom of the seat using the template (figure C).
- Once the wedges have been cut away, the bottom surfaces are flattened using the jointer. This part of the process is somewhat tricky since it essentially involves flattening separate "facets" on the bottom surface. The seat is placed on the jointer surface and rocked forward (figures D and E ) to flatten the first surface, leaving it dead-on flat for the joinery. The same process is used to flatten the bottom surface on the other end.
- The joinery used for the bench seat uses integral tenons cut into the legs (figure F) and matching mortises cut into the bottom of the seat.
- A mortising template (figure G) makes it easier to position and cut the mortises into the bottom surface of the seat. A stop glued onto the end of the template references off of the end surface of the seat to help ensure accuracy.
- The template is positioned and clamped in place, and a handheld plunge router with a flush-bearing bit is used to rout out the mortises (figure H). The bearing on the bit follows the template, making for a quick, easy and accurate method of cutting the mortises.
- Since the router-cut leaves rounded ends, the template is left in place and a chisel used to cut the ends of the mortises square (figure I). The squared mortises will match the tenons that will be made next.
- With the mortises cut in the seat, work begins cutting the integral tenons into the leg stock. A curved template placed onto the end of the leg stock (figure J) indicates the eventual shape the seat will take as well as the positions of the tenons. Because of the curved shaping that will occur later, the tenons must be positioned off the centerline of the leg stock.
- With the template traced on the top of the leg, the outside cheeks of the tenons are cut on the table saw using a ripping blade and a fence set up at 5/8". The fence is then adjusted to cut the inside cheeks (figure K).
- The table saw is then reset to make some notch cuts across the end grain.
- The combination of cuts defines the boundaries of the two tenons (figure L ).
- Next, the crosscut sled on the table saw is used to cut around the perimeters of the shoulders, leaving the two integral tenons (figure M).
- Important: Because the tenons are offset, it's important to carefully check the height of the blade when cutting the cheeks and shoulders of the tenons.
- With the joinery made, the pieces of the bench can be dry-clamped into position to ensure solid fit and check measurements.
- With the structure dry-clamped together, marks are created for making angled cuts on the bottoms of the leg pieces. The counterangled cuts on the bottoms of the angled legs will allow the bench to sit level on the floor once the elements are assembled. With the pieces dry-clamped, the flat top surface of the seat can be used as a reference for setting up measurements for the cut (figure N).
- With the appropriate measurements established (in our example, the length of the legs was 21") a straightedge is positioned across the angled legs, and pencil marks are made for the cuts (figure O).
- The band saw is used to make the angled cut on the bottom of each of the legs (figure P), following the pencil marks.
- The top and bottom templates provide the dimensions for the legs, so those measurements are used to lay out the marks for the tapered sides (figure Q).
- The wedge-shaped side pieces are cut away on the band saw (figure R), following the marks to create the tapered shape.
Creating the Purpleheart Accent Pieces One of the key design elements on the bench is the sculpted purpleheart wood disc that accents the outside of each of the leg pieces (figure S). - Rather than simply gluing the disc to the side of the leg, a circular piece is cut out (figure T). The bottom of the disc will fit into this circular recess when it's installed later.
- A circular template is used for cutting out the recess using a handheld router and flush bearing bit. The router and bit is set to cut out a recess that is 3/16" deep.
- The band saw is used to cut the circular discs out of purpleheart stock (figure U).
- Once the discs have been cut, they need to be made perfectly symmetrical and identical using a disc sander. To facilitate the process, a special jig is made for the sander table. The jig is a pivoting arm, hinged at one end, and with a pin fixed in place. The pin fits into a hole that's been drilled into the center of the purpleheart disc. The arm then pivots up against an adjustable stop that controls the depth of the cut. The disc, held in position by the pin, then rotates against the disc sander (figure V). The disc sander cuts away the excess material, creating a perfectly symmetrical disc.
- Once the two identical discs are complete, they are sculpted into their finished dome shape. This might be accomplished with hand tools, but since purpleheart is a very dense hardwood, a pneumatic die-grinder and carbide ball-mill are used instead. This tool is especially useful for sculpting dense hardwoods.
- Each disc is held in place -- in a circular recess cut in a piece of scrap poplar -- with doublestick tape. Once secured in the recess, the die-grinder is used to create the textured dome shape (figure W) out of the disc.
In the next phase of the project, the legs and seat of the bench are sculpted and shaped. Sponsored Resource
> Click here to order your tools and materials for this project from Woodcraft!
RESOURCES :
Fine Woodworking
A magazine devoted to high-quality craftsmanship in woodworking.
The Taunton Press Inc.
Website: www.taunton.com
The Small Wood Shop (The Best of Fine Woodworking)
Author: Helen Albert (Editor)
Publisher: Taunton Press
ISBN: 1561580619
Woodworking Techniques: Best Methods for Building Furniture from Fine Woodworking
Author: Editors of Fine Woodworking magazine
Publisher: Taunton Press
ISBN: 1561583456
Mastering Woodworking Machines (Fine Woodworking Book)
Author: Mark Duginske
Publisher: Taunton Press
ISBN: 0942391985
David Marks Website
David Marks, DIY's Wood Works host, is a master woodworker. For more information on cut sizes and project details, please contact him via his Website at www.djmarks.com
The Complete Book of Wood Joinery
Author: Robert J. Decristoforo
Publisher: Sterling Publishing Co.
ISBN: 0806999500
Advanced Woodworking
Model: 0783539126
Author: Editors of Time Life Books
1998
Time-Life Books Inc.
Website: www.timelife.com
Popular Woodworking
F & W Publications, Inc.
Website: www.popularwoodworking.com
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