Build It | Modern Platform Bench

Given the popularity of mid-century modern furniture, Tom Silva sensed a great Build It opportunity when his son showed him a reissue of the George Nelson platform bench. Tom saw that the clean lines of the elegant 1946 design were achieved with straightforward woodworking techniques: the bench top’s half-lapped strips would be easy work for a table saw and router. The legs’ trapezoidal shape might pose more of a challenge, but loose-tenon joinery could take care of that.

Instead of the birch used in the original, Tom chose to make the bench out of ipe decking, a dense hardwood that’s prized for its rich hue, knot-free surface, and durability. Its sawdust can irritate nasal passages, so he and Kevin O’Connor hooked up their tools to vacuums when sanding and cutting it.

It took them 4 hours to assemble this bench, with $100 in materials. Not a bad investment for a reproduction piece that normally retails for around $1,000.

How the Bench is Made

Steps for Building a Modern Platform Bench

1. Prepare the slats

• Using a table saw, rip the decking in half, to about 13⁄4 inches wide.
• For the legs, rip the stock down to 21⁄8 inches wide.
• Sand the sharp corners made by the saw.

2. Cut the leg pieces

• Mark the length of each leg piece, then use a miter saw to miter the ends of all eight leg pieces. (See “How It’s Made,” above, for the angle of each cut.)
• Fit the ends tightly together and draw two parallel pencil lines 1 3⁄4 inches apart across each joint.

3. Make the mortises

• Set the angle of a Domino joiner fence to match the miter angle of a leg piece.
• Line up the joiner with one pencil line and plunge its bit into the leg’s end grain. Do the same at the neighboring line.
• Repeat on the ends of every leg piece, until you have a total of 16 mortises.

4. Assemble the legs

• Squeeze glue into the mortises on both sides of a leg joint; insert the tenons into the mortises on one side.
• Spread glue over the end grain on both leg pieces, and push them together. Do the same on all eight leg pieces.

5. Clamp the leg assemblies

• Tighten two bar clamps on the top and bottom of each leg assembly, and leave them in place for at least 30 minutes.
• Check that all the joints are aligned, and wipe up any glue that squeezes out with a damp rag.

Don’t Let That Glue Show

Glue that squeezes out of a clamped joint is a normal and expected part of the woodworking process. But it’s important to wipe up every drip before it dries, leaving a stain-resistant discoloration on the wood’s surface.

In most cases, a damp rag will do the trick, but when a rag can’t reach the glue nestled deep in an inside corner, other cleanup tools can be employed, such as a beveled-edge bench chisel, shown at right. Just make sure to thoroughly clean any glue off it, too.

6. Rout the slats

• Build a sled for the router to gang-cut the 3⁄4-inch-wide dadoes in the slats.
• Clamp the long slats together between a pair of long 2x3s set on edge; place the sled on top of them and clamp it down, too. Make three or four shallow passes until the notches are 7/8 inch deep.
• Shift the position of the sled and rout the three remaining sets of dadoes in the same way.
• After each set is done, fit a scrap crosspiece in the freshly cut dadoes to keep the slats from shifting.

7. Notch the crosspieces

• Clamp together and rout dadoes in the four crosspieces, using the method in Step 6. Each piece will end up with 10 notches.
• When you’re done routing, unclamp them and sand both faces of each piece, as shown.

8. Assemble the top

• Squeeze a dab of wood glue into the bottom of the notches in all the slats and crosspieces.
• Fit the downward-pointing notches of the first slat into the first row of upward-pointing notches in the crosspieces.
• Tap the slat into place with a rubber mallet. Repeat with the remaining slats.
• Wipe up any glue that squeezes out.

9. Fasten the top’s joints

• Use a countersink bit to drill into the center of each stringer where it laps a crosspiece. Then drive a deck screw into each pilot hole.
• Wipe away any drips.

Tip: Prep the Bench to go Outside

The ipe will do fine out in the weather, but the glue and screws used here need the protection of a porch roof. To make this a truly weatherproof bench for use outdoors, glue the legs, slats, and crosspieces with a Type III waterproof wood glue, and fasten them with no-rust, 316-grade stainless-steel screws.

As for the ipe, you can let it turn gray, for the ultimate low-maintenance surface. Or coat it with a low-VOC, penetrating tung oil such as ExoShield Premium Wood Stain to help the wood retain its deep, rich color.

10. Trim the slat ends

• Cut the projecting ends of the slats flush with the crosspieces. This can be done with a track saw or a Japanese flush-cut handsaw.
• Smooth the end pieces with 100- and 180-grit sandpaper.

11. Attach the leg bases

• Locate them so they’re equidistant from the sides of the bench and 8 inches from the ends.
• Use a large rafter square to set one base perpendicular to the bench top’s edge. Drill four pilot holes through the base and into the slats, as shown.
• Drive a screw into each hole. Repeat with the other leg base.

12. Mount the legs

• Center each leg on its base; drill four pilot holes into the leg’s top piece.
• Drive screws into the pilot holes. The bench is now ready to be finished and to take its place in your home.


Resources

Tom and Kevin built the bench out of ipe deck boards, which can be found at any home center. Tom liked the idea of ipe for the bench so it could be used for either an indoor or outdoor application.

To cut all the boards to the proper dimensions and assemble the bench, Tom used a variety of tools, including a Domino Joiner, a Kapex KS120 sliding compound miter saw, a TS 55 circular saw, which are all manufactured by Festool, and an Industrial Table Saw from SawStop.

Tom and Kevin secured everything together using GRK #8 1-1/2″ multi-purpose screws from GRK Fasteners and some wood glue from Gorilla Glue.

All of the other tools and materials Tom and Kevin used to build the bench can be found at home centers.

Materials

• 1×3 ipe decking (about 40 linear feet)
• 100- and 180-grit sandpaper
• 4×20 mm Domino tenons
• Wood glue
• 1¼-inch #8 Torx-head deck screws

Tools