27π (Furniture Design @ RISD)

The Idea

The problem with most benches is that they’re built in a straight line, making it awkward to talk to people who aren’t sitting right next to you. This issue led me to design a bench that encourages conversation. By using a semicircular shape, everyone faces toward the center, so it’s easy for people to see each other and talk naturally.

I call it 27π, named after the circumference of the bench’s semicircle.

Preliminary Drawings & Mini 3D Models

Preliminary Drawings

After starting with a rough sketch on paper and a larger 1:4 scale draft, I created this 1:2 scale preliminary drawing in Onshape. I also calculated the exact dimensions for each wedge and made a paper template, so I could repeat the same wedge shape consistently during manufacturing.

Left: Onshape 3D model of the bench.
Right: The 3D printed mini model.

Manufacturing

Cutting the Wedges Using a Bandsaw

After purchasing wood in two different thicknesses (6/4″ and 5/4″), I marked all the required parts directly on the boards in pencil, including their exact dimensions. Then I began the wood preparing process using the milling machine, planar, and table saw.

Using a paper template, I traced the wedge shape onto the wood and cut each wedge with a bandsaw. The initial cuts were slightly uneven, so I sanded the pieces until they all matched in shape and size.

Top View

I cut out the large semicircle pieces using a jig saw. I drew the circles using a piece of string, a pin, and a pencil.

Bottom View

I arranged the pieces roughly in their spots to check dimensions.

Cutting and Screwing on the Front legs & Wedges

I next cut the front legs using a table saw and screwed them on.

Wedges got screwed on from underneath.

Cutting and Screwing the Back Legs

The back legs were also cut using a table saw and then screwed on from the side. The legs were a bit flimsy, which is why I added supports and two screws on each back leg instead of one.

Adding Supports

To correct the previous issue, I added support between the front and back legs for added stability.

Final Result After Sanding and Applying a Tung Oil Finish

I sanded the whole bench four times with four different grits of sandpaper. I then applied two coats of tung oil, with time to dry in between each coat.

Some More Photos

27π in the Majors Exhibition at RISD

27π in my Sunroom at Home

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