Office Chair Shaft Instability

When an office chair shaft is unstable, first investigate structural shaking and floor sliding as potential causes, then address them accordingly.

Structural Shaking

• Loose Connecting Components: After prolonged use, the screws and bolts at the joints between the chair seat and legs may loosen. If you hear a creaking sound or feel gaps at the connections when shaking, it's likely due to loose fasteners. Use an appropriate screwdriver or wrench to check and tighten the screws and bolts at various points on the chair, especially where the legs connect to the seat and backrest.
• Uneven Leg Lengths: Some chairs may have slight manufacturing errors, or one side of the legs may wear unevenly due to prolonged use, resulting in different leg lengths and causing the chair to tilt consistently to one side. This issue is more common in wooden or older chairs.
• Damaged Frame Structure: For solid wood chairs with mortise-and-tenon joints, prolonged stress can cause the tenons to loosen, crack, or even break. These problems may not be easily visible to the naked eye, but sitting on the chair may make it feel 'soft' or noticeably lean to one side. If tenon looseness is detected, timely reinforcement is necessary.
• Reinforce Triangular Structure: For chairs with loose structures and frames prone to deformation, reinforcement can be achieved by referencing the principle of diagonal beam anchoring. Nail or firmly glue a wooden strip or metal bar diagonally between adjacent chair legs on both sides of the chair, converting the originally unstable quadrilateral frame into a stable triangular structure, which can greatly suppress shaking.

Floor Sliding

• Uneven Floor: Grout lines between tiles, slight depressions in wooden floors, or the presence of soft floor mats may prevent all four legs of the chair from making even contact with the ground simultaneously. Especially for chairs with a wide leg span, even a few millimeters of height difference on the floor can cause noticeable shaking when sitting. Try moving the chair to a different location; if the shaking disappears, the floor is uneven. In this case, temporary solutions include sticking or inserting shims, such as cardboard, thin wooden pieces, or multiple coins, under the shorter legs. Alternatively, specialized adjustable-height furniture feet or rubber shims can be used.
• Low Friction Coefficient Between Chair Feet and Floor: If the material of the chair feet (such as hard plastic or metal) has a low friction coefficient with smooth tile or wooden floor surfaces, it can also cause the chair to slide. Self-adhesive anti-slip pads or EVA protective pads can be attached to the bottom of the chair feet to increase friction while also providing noise reduction and preventing floor scratches. Chair leg covers made of silicone offer excellent elasticity, anti-slip, and wear resistance, and are easy to install. Felt pads provide good sound insulation and protect soft floors like wooden ones well, but their anti-slip performance is weaker on smooth hard surfaces like tiles and they are susceptible to moisture. Anti-slip tape can be cut and wrapped around, suitable for irregularly shaped chair legs, offering strong fixation but may leave residue when removed. Additionally, laying carpets or specialized anti-slip mats in the area where the chair is frequently moved can fundamentally increase overall friction, prevent sliding, and protect the floor.