Beacon - taekwondo lamp and bookend

A gift that had to hold books up and be worth looking at. Most of the work went into reaching a shape you cannot buy as stock.

The finished lamp lit on a nightstand: a curved black arm rising from a wooden base into a lantern with a kicking figure on its panels, a flat spiral coil at the foot holding a row of books, and a strip of light along the base.

the problem

A gift for someone who does taekwondo, which had to earn its place on a desk and hold books up while it was there. The shape I wanted - a curved arm and a flat spiral - is not something you can buy as stock, so most of the project was working out how to get to it.

what I did

Sketched 4 ideas and took the lamp forward. Priced the cutting both ways first: every profile waterjet out of 1 inch plate at $60 a sheet and stacked, or cut straight through 2 inch plate at over $200. Took the thinner stock. Cast the coil in sand from a pattern and milled its mounting points afterwards. The rest was milling - edge find, face, drill, tap, counterbore, countersink - with a lot of strap clamp set-ups and angle blocks to hold curved parts square. The base is wood, routed for a light strip, with the transformer pocketed underneath.

what happened

It works and it is in use, lit, with books in it. The casting took 6 goes at the mould - the first lost to break-off where I had not left enough draft, the rest to flasks that had deformed - and the casting that came out was usable. The mill only added the mounting points.

what I learned

Waterjet draft has to be accounted for on thick parts. Corner rounding should only be done on simple geometries - I found that out on a curved part and got away with it by offsetting 5 degrees to blend. Wiring always needs more room than you have left it. The last of it is not about machining at all: photograph more of the process while it is happening, and ask for help sooner.

Five processes

Sand casting	the coil, from a pattern
Waterjet	every profile, cut from 1 inch plate and stacked
Milling	mounting points, holes, threads and the blended edge
Laser cutting	the lantern panels, and the figurine lit on the bookend
Woodwork	the base, routed for the light strip

Idea

Four concepts before anything was cut: a kicking figure, a belt display case, a clock, a pen holder. The lamp won because it had a job to do when it was switched off.

Two notebook pages of sketches: four concepts on the first, and on the second a developed lamp with dimensions and base options. — **Fig 2** The sketch page the project came from.

A mock-up in foam and board, lit from inside, standing beside books on a bench. — **Fig 3** Foam and board, to see whether it was worth making.

Design

The assembly and the exploded view. A pair of arms sandwich the coil, the lantern sits on standoffs between a top and bottom plate, and everything lands on the wooden base.

CAD of the whole assembly: arm, lantern, coil, bookend and base. — **Fig 4** The assembly.

The coil

The parts are thicker than the plate I bought, so every profile was cut from 1 inch stock and stacked. The coil went a different way: a pattern, a sand mould, and the mill afterwards for its mounting points.

The arm and coil profiles cut through a sheet of aluminium plate on the waterjet, the parts still sitting in the sheet. — **Fig 6** Profiles out of the waterjet.

The casting pattern for the coil, in white, on a bench. — **Fig 7** The pattern.

The closed sand mould in its flask, the coil impression visible in the parting face. — **Fig 8** The mould, rammed up.

The pattern beside the raw casting, still rough from the sand. — **Fig 9** Pattern and casting, before the mill.

On the mill

Most of the hours. Curved parts do not sit square in a vice, so nearly every operation needed its own set-up.

A coil backing clamped to the mill table under strap clamps, being drilled. — **Fig 10** Strap clamps, again.

A part held against angle blocks on the drill press table. — **Fig 11** Angle blocks, to hold a curve square.

The curved arm on the machine part-way through the corner rounding operation, its edge half broken. — **Fig 12** The corner rounder, where it went wrong.

A close-up of the finished arm, its rounded edge blending into the flat face. — **Fig 13** And where it was recovered.

Lantern and base

The lantern is a pair of waterjet plates on standoffs with laser-cut panels between them. The figurine on the bookend is laser cut too, and lit from the base. The base hides the wiring, which is the part that needed the most room and got the least.