lloydsbsbs London furniture notes

Note 04

Loose joints, and what the wobble is doing

A chair can feel loose because one joint has opened, because the whole frame is racking like a parallelogram, or because the floor is not flat. Those are different findings.

Published · Updated

A marking gauge setting a line on the edge of a timber block
Layout on solid timber, shown as an illustration of jointed wood. Not the publisher’s bench.

A rack, drawn simply

Put the chair on a surface you know is flat. Hold the seat. Push a back corner gently toward the opposite front leg. Watch whether the shoulder opens. That movement is racking.

Joints are the places where one part of a frame enters another. A mortise and tenon is a tongue in a pocket. A dowel is a peg in two holes. A dovetail locks a drawer corner with wedge-shaped pins. Flat-pack furniture often uses a cam and a bolt, or a screw into particleboard. The name matters less than whether the two faces still meet on bare wood, and whether anything is cracked.

Glue holds on clean wood. It does not hold on polish, wax, or dust. A shiny socket that a dowel has pulled out of will not become strong because more glue was wiped over the shine. Forcing a glued joint shut while the wood is crushed, or while a broken peg is still inside, opens the split further. If a leg is cracked through, sitting on the chair can finish the break. Take it out of use.

  1. PLATE 01 · CHAIRS

    Back posts and stretchers

    Side-to-side wobble at the top of a back often starts in the joint between the back post and the seat, or in a stretcher near the floor. Look for a dark line that opens when you rack the frame and closes when you let go. That line is the joint. A line that stays open is a split in the wood. Seasonal opening of a mitre on a decorative bead can look similar and is described in the timber note. If the opening is only in winter and the chair does not rack, do not treat it as a failed glue line.

  2. PLATE 02 · TABLES

    Aprons and tops

    A table can rock because one leg is short, because the floor dips, or because an apron joint has opened. Test on another part of the floor before you pack a leg with card. Tops that are screwed hard to the apron cannot shrink across the grain. The screw slots, or the lack of them, are part of the joint story. Do not drive a longer screw up through the apron into a thin top to “stop the rock”. You can come through the face.

  3. PLATE 03 · BOARD FURNITURE

    Cams and stripped holes

    Particleboard and some fibreboards do not hold a screw the way solid timber does. A hole that spins is stripped. A cam lock that turns forever is not catching the bolt. The fix is rarely “a bigger screw in the same dust”. It may be a larger fitting, a plug, or a different place for the fastener, and those choices depend on what is behind the face. The veneer page helps you see whether you are looking at a printed board. Hinge plates on the same doors are covered under hardware.

  4. PLATE 04 · A NARROW CASE

    A clean, open dowel on a plain chair

    Sometimes a dowel has come out whole, the hole is bare wood, and the chair is a plain modern frame rather than an old polished one. People then dry-fit the joint, check that it closes without a crack, remove crumbled glue from both faces, and close it while it is held square. That is a narrow situation. If the peg is broken inside the hole, if the wood is crushed, if the finish runs into the socket, or if you do not know what the old glue is, stop. Soaking an antique joint to soften glue can lift the finish around it and stain the wood. This page is not a soaking method.

Pause and keep looking

The joint opens and closes, the wood around it is intact, and the chair still stands when no one sits in it. Record the movement. Read the timber page if the season is the variable.

Stop using it as a seat

A leg is cracked through, a back post is split, or the frame folds when weight goes on. Keep the loose pieces. Do not stand on the seat to “test” it.