| Cherry Sofa-Table -- Curved Stretchers |
From "Wood Works"
episode WWK-404 |
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In this episode of DIY Wood Works, host David Marks builds a simple, sturdy sofa-table. A traditional design with a contemporary flair, this elegant table is made from solid cherry and features a sweeping bent-laminated stretcher. The solid top is beveled along the underside, lightening the feel of the piece, and the curved stretchers add visual interest as well as stability and strength. The aprons curve gently and are joined to the legs with mortise and loose tenons. The clean, simple lines of the table and beveled legs are enhanced by the symmetrical bottom-stretcher. The design for this table was inspired by the work of English master furniture-maker Edward Barnsley. His simple, graceful style is showcased in this elegant table. The curved lines of the stretchers used in the design give woodworkers the opportunity to utilize bent-wood lamination techniques. Materials:
Cherry stock
MDF for mockup
Cork sheeting for bending form
Table saw
Band saw
Belt sander
Jointer
Table router; flush-bearing bit
Compass
Slow-setting plastic-resin glue
Glue roller
Clamps
Straight-edge
Carpenter's pencil
Safety glasses or goggles
Note: Cut sizes may vary. For exact measurements, please contact David Marks through his Web site -- information below under Resources. Safety Alert: Always wear safety goggles or safety glasses when working with wood, power-tools, saws, drills, routers, etc. Bending Form and Bent-Wood Lamination Steps: - The project begins with full-scale drawings on MDF for the side-views and a top-view that shows how the stretcher joins the legs (figure A).
- After determining the rough dimensions, draw out the footprint for the legs on a sheet of MDF. Then use thin strips of wood that can be bent easily to work out the curve of the stretcher. The challenge is to create an aesthetically pleasing curve that strengthens the base.
- Set the strips on the center-line of the sketch, clamping them straight for about 8 inches in the center, and experiment until you arrive at a suitable curve. For our table, we bent the strips sweeping toward the legs, and marked the locations where they meet the corner of the leg at a 45-degree angle (figure B).
- Tip: When wood is bent to create curves, it is likely that some spring-back will occur. Wood has a natural tendency to return to its original shape, following its natural grain. The best way to minimize spring-back is to cut thin laminates. The thinner the laminates, the less spring-back you're likely to have.
- Because some spring-back is inevitable, it's impossible to know the precise dimensions of the aprons until the stretcher is made. For that reason, the bent stretchers are the first elements made in this project. The final dimensions of the overall design will be adjusted later, based on the dimensions of the final curve.
- To bend the wood, a bending form is required. Begin making the bending form by first transferring the outside line of the desired curve onto a thin sheet of paper (figure C). Using carbon paper, then transfer the traced line onto some 3/4-inch MDF.
- At the band-saw, cut out the curve just shy of the line (figure D). Cutting slightly oversized will allow the curve to be shaped after cutting.
- Use a pattern-maker's rasp to shape the edges of the curve (figure E), then smooth it using a sanding strip. This finished curve is the master for the male side of the bending form.
- To make the opposing side of the form, you'll need to take into consideration the final thickness of the stretcher -- 5/8-inch. Also, an additional 1/8-inch is needed to accommodate a piece of cork. With these dimensions in mind, use a compass to scribe a line that is 3/4-inch beyond the edge, and exactly parallel to the edge of the existing curve. Set the compass at 3/4-inch, and follow the curve of the existing side of the form (figure F), tracing the line onto another piece of 3/4-inch MDF.
- Cut the curve at the band saw.
- Use a rasp to shape the edge (figure G), and a sanding strip to smooth it.
- Once there is an MDF master for each side of the bending form (figure H), build the form by cutting, stacking, and flush-trimming MDF to create a total of six layers of 3/4-inch MDF.
- The finished form is 4-1/2 inches tall (figure I). This tall form allows glue-up of wide laminates -- wide enough to be cut in half to create the two mirror-image sides of the stretcher.
- Cork is added to the edges of the form (figure J) to help smooth out any imperfections in the form and even out the clamping pressure.
- It's important to mark the center-point on both sides of the form (figure K), to ensure that the halves can be lined up accurately during glue-up.
- With the bending form complete, the next step is to cut the 8/4 cherry stock into thin laminates at the band saw (figure L). Cut a total of 10 slices, with each slice 3/32-inch thick.
- A triangle marked on the edge of the stock (figure M) helps keep the slices in order to make sure that the grain will match when the slices are glued up.
- Pass each laminate through the drum sander (figure N) to bring them all to a uniform size.
- To glue the laminates together, apply (figure O) and roll on a thin coat of slow-setting plastic-resin glue. Apply glue to all surfaces except for the outside surfaces.
- Once the glue has been applied, stack the laminates -- making sure to stack them in the proper order -- and place the bundle in the bending form (figure P).
- Bring the two sides of the form together tightly using several clamps (figure Q) to provide even clamping pressure, making certain that the marked center-points of the form are aligned. Allow the laminates to cure for 24 hours.
- Once the glue has dried, remove the bundle from the form and transfer the center-line onto the curved stock.
- Use a belt sander to remove the hardened glue from one side of the curved stock (figure R).
- Flatten the sanded side smooth using the jointer (figure S).
- Set the jointed edge against the fence of the band-saw, and cut the curved stock in half (figure T). Each side of the stretcher is 2 inches thick.
- Make a second trim-cut on the band-saw to remove the glue on the opposite edge.
- With the curved stock cut, we clamp the two halves together. As predicted, there is a bit of spring-back present in our curved pieces. For this reason, some slight adjustments will need to be made on the full-scale drawing. For our table, the spring-back was about 3/16-inch. For that reason, the dimensions for the table will have to be made slightly narrower than the original design. Once the design has been adjusted, the template is used to mark the ends of the stretcher (figure U) where they will ultimately join the legs.
- At the table saw, cut the ends of the stretcher according to the new adjustments. Use a wedge to hold the stretcher stock at the proper angle (figure V). Repeat this step for all four stretcher-ends.
- Glue the stretchers together at the mid-point using yellow glue, and clamp the assembly together securely (figure W) until the glue dries.
In the segment that follows, the legs are made and the joinery is cut. 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
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