Most cabinet tutorials begin with a sheet of plywood and a table saw. This one begins with a chrome ball about an inch across, threaded on six faces, and ends with a hex key.
Watch first: one frame, assembled in 45 seconds
No sound, 45 seconds. The frame is our USM Haller style coffee table; a cabinet uses the same joints, with more panels.
In the film
- Parts
- Pre-tighten the connectors
- Insert the tubes
- Close the frame
- Uprights and top
- Lock with a hex key
Search for how to build a cabinet and nearly every answer is carpentry: cut the sides, drill the pocket holes, glue and square the box, then hang the doors. It works, but it assumes a workshop, a free weekend and a tolerance for sawdust. There is another way to build a cabinet that needs none of that, and it has been around since the 1960s.
Between 1962 and 1965 the Swiss architect Fritz Haller and Paul Schärer Jr., who ran the metalworking company USM, developed a furniture system from three parts: chrome-plated steel tubes, a ball connector and flat panels. USM filed the patent for the ball connector in 1965, and the system entered the collection of the Museum of Modern Art in 2001. Our USM Haller style pieces and connector kits follow the same construction logic. This guide shows how a frame goes together, how to count the parts for the cabinet you want, and when it makes more sense to buy one ready-made.
Two ways to build a cabinet
A cabinet is a box that has to stay square while it carries weight. Woodworking makes the box rigid with glued joints and a back panel. A ball-and-tube frame makes it rigid with a grid of steel tubes locked into a connector at every corner, then closes the faces with panels.
| Woodworking | Ball-and-tube frame | |
|---|---|---|
| Tools | Saw, drill, clamps, sander, square | One hex key |
| Skills | Measuring, cutting, gluing, squaring | Counting parts and keeping the frame square |
| Mess and noise | Sawdust, glue and finish fumes | None |
| Time for a small cabinet | A weekend or more, plus drying time | Minutes to an hour for a ready-made piece; longer from loose parts |
| Changing it later | Rebuild or add a second box | Add a bay or a tier with more connectors |
| Moving house | It moves as one box | Unbolts back into tubes, balls and panels |
Woodworking times vary with experience. Frame times are those of our ready-made pieces; see the FAQ.
How the ball joint works
Every corner of the frame is a chrome-plated ball about 1 in (25 mm) across, drilled and threaded M8 on all six faces. Up to six tubes can meet at one ball: left, right, front, back, up and down.
The tubes do not screw into the ball directly. An expansion connector does the joining: a slotted sleeve and a split core around a hex-socket screw. It screws into the ball, the 0.75 in (19 mm) round tube slides over it, and tightening the screw with a hex key expands it inside the tube so the tube is held fast. No glue is involved, and the joint comes apart again when the screw is loosened.
These are the specifications of our parts. We do not claim they fit original USM furniture: before mixing parts with a piece you already own, measure its thread and its tube diameter.
Our parts at a glance
- Ball connector
- 25 mm (1 in), chrome-plated, M8 thread on six faces
- Expansion connector
- 16 × 30 mm, for 19 mm (0.75 in) round tube
- Tool
- Hex key, included with every connector kit
- Not included in the kits
- Tubes, panels and casters
Plan the grid: a parts calculator
Decide the grid before you buy anything. A cabinet one bay wide and one tier high is a cube: eight corners and twelve tubes. Each extra bay or tier shares the corners next to it, so the number of parts grows more slowly than the cabinet.
For a grid W bays wide, H tiers high and one bay deep, the counts are:
- Balls = 2 × (W + 1) × (H + 1)
- Tubes = 2 × W × (H + 1) + 2 × H × (W + 1) + (W + 1) × (H + 1)
- Expansion connectors = 2 × tubes, one at each end of every tube
| Grid | Balls | Tubes | Connectors | Kits that cover it |
|---|---|---|---|---|
| 1 wide × 1 high | 8 | 12 | 24 | Side Table Kit |
| 1 wide × 2 high | 12 | 20 | 40 | Nightstand Kit |
| 2 wide × 1 high | 12 | 20 | 40 | Nightstand Kit |
| 3 wide × 1 high | 16 | 28 | 56 | Nightstand Kit + Side Table Kit |
| 2 wide × 2 high | 18 | 33 | 66 | Nightstand Kit + Side Table Kit + Expansion Connector 3-Pack |
The kits contain the joints only. Tubes come in fixed module lengths, so choose the grid first and buy the tubes to match. For reference, the most common module sizes in the original system are 750, 500 and 350 mm wide by 350 mm deep (about 30, 20 and 14 in by 14 in), and our coffee table frame measures 30.5 × 20.6 × 14.7 in: see its dimension drawing.
Step by step
The film above shows the order on a one-bay frame, and the steps below follow it move by move; a cabinet goes together the same way. Work on a clear floor or a blanket, with the parts sorted before you start.
Lay out the parts
Sort the balls, connectors, tubes and panels by size, and check the counts against the calculator above. Keep the hex key within reach.
Pre-tighten the connectors
Screw an expansion connector into each ball face you will use, finger-tight. Leave them loose enough to turn: the final lock comes last.
Insert the tubes
Slide a tube over each connector until it meets the ball. While the connectors are loose, the tubes can still be turned into line.
Close the bottom frame
Build the bottom rectangle around its panel. Measure both diagonals: when they are equal, the frame is square.
Add the uprights and the top
Stand the vertical tubes in the bottom balls, then lower the top frame and its panel onto them, one joint at a time.
Lock every joint
Go round the frame with the hex key and tighten each connector until its tube no longer turns. Tighten opposite corners in turn, as you would the wheel nuts on a car, so the frame pulls square.
X-ray view: the tubes and the ball are drawn see-through, so the key and the connectors show.
Check level and square
Set the cabinet in place and check it with a level. If a panel will not seat, loosen the nearest joints, square the frame and lock it again.
Locked and square: the same joints, closed with side, back and door panels, make a cabinet.
Panels, doors and drawers
A frame becomes a cabinet when its faces are closed. Shelf, side and back panels close the box, and a back panel also stops the frame from racking sideways.
Doors and drawers need their own hinged or sliding parts, sized to the module, and those are the hardest pieces to source on their own. If you want them, start from a piece that already has them. Our USM Haller style nightstand closes behind a soft-close drop-down door and ships fully assembled. The three-bay TV stand has three soft-close drop-down doors and goes together on site; most customers finish it in under an hour with a second pair of hands.
Build from parts or buy ready-made
If you already own a frame and want one more bay, a connector kit is the shortest route. If you are starting from nothing and want doors, a ready-made piece saves the sourcing and the squaring.
| Build from parts | Buy ready-made | |
|---|---|---|
| What you buy | A connector kit, plus tubes and panels from a supplier | A finished USM Haller style piece |
| Joints for a two-tier cabinet | Nightstand Kit, $182.20 | Included |
| Doors | Not part of the kits | Nightstand: one drop-down door; TV stand: three |
| Assembly | Planning, sourcing and a full build | None for the nightstand; under an hour for the TV stand |
| Best for | Odd sizes, or extending a frame you own | A first cabinet, or a cabinet with doors |
Prices as listed when this guide was published.
Fixes and safety
- A panel will not drop inThe frame is out of square. Loosen the joints around that panel, measure both diagonals, and lock the joints again once they match.
- The frame wobblesAdd a back or side panel, and tighten the joints in opposite pairs.
- The floor is unevenLevel each tier before the final lock, then adjust the feet or casters.
- Never loosen a loaded jointEmpty the shelves before you loosen any connector.
- Anchor tall cabinetsFix any cabinet taller than about 27 in (69 cm) to the wall, especially one with doors or drawers that a child could climb. That is the height at which US tip-over rules for clothing storage begin.
Frequently asked questions
Do I need power tools to build a cabinet this way?
No. Every joint is locked with a hex key, and one comes with every connector kit.
What comes in the Side Table Kit and the Nightstand Kit?
The joints only: 8 balls and 24 expansion connectors for a one-bay frame, or 12 balls and 40 connectors for a two-tier or two-bay frame, plus the hex key. Tubes, panels and casters are not included.
Can I add a bay later?
Yes. A new bay shares the balls on the side where it joins, so a second bay beside a one-bay frame needs four more balls and the connectors for its tubes. Run the calculator again with the new grid and buy the difference.
Will these parts fit original USM furniture?
We do not claim compatibility. Our balls are threaded M8 and our connectors fit 19 mm (0.75 in) round tube: measure your piece before mixing parts.
How long does assembly take?
It depends on the piece. The nightstand ships fully assembled, the coffee table arrives about 80% assembled and takes about ten minutes, and the three-bay TV stand usually takes under an hour with two people. A frame built from loose parts takes longer, mostly in sorting and squaring.
Parts and pieces in this guide
The USM Haller Style Room-by-Room Design Guide shows the system in dining rooms, living rooms and bedrooms, and includes a 15% code.
Keep exploring
- USM Haller coffee table dimensions and drawings
- The 26-second assembly film
- All USM Haller style films
- Bauhaus design style, room by room
BREUER HOME is not affiliated with USM U. Schärer Söhne AG. “USM Haller style” describes the design tradition our pieces follow; they are not original USM products.
