Replacing a chair cap requires precise measurement to ensure a perfect fit. This guide explains step-by-step how to take the right measurements and choose the correct glide for your chairs and tables.

Required equipment

  • A digital caliper (also called a sliding caliper)
  • A pencil and paper to note the measurements
  • A flat surface to work on

Step 1: Measuring the outside diameter of the leg

  1. Close the caliper and press ZERO to tare it
  2. Open the caliper and place it perpendicular to the chair tube
  3. Ensure the caliper jaws are in full contact with the surface
  4. Tighten gently until contact is established
  5. Record the measurement in millimeters precisely
  6. Note this measurement: this is your reference outside diameter

The caps must be chosen according to this outside diameter you have just measured. For example, if the outside diameter of the chair leg is 20mm, then the suitable cap must also be 20mm in diameter. Our caps are named and organized according to their outside dimensions.

Step 2: Checking the inside diameter of the cap

  1. Measure the inside diameter of the cap with the caliper
  2. Use the small prongs of the caliper for the inside measurement
  3. The measurement should be slightly larger than the outside diameter of the tube
  4. A difference of 0.5 to 1 mm is acceptable to ensure a secure fit

If the inside diameter of the foot falls within the range mentioned on the cap’s product sheet, then your cap will be suitable. For example, the foot has an inside diameter of 16mm and the selected cap specifies an inside diameter between 15 and 17mm, then it is the right cap.

Important tips for measuring plastic chair caps

  • Use a caliper for exact precision. A metal ruler may also work. Do not use a tape measure or tailor’s tape, which provide imprecise measurements.
  • Take several measurements to ensure accuracy
  • Clean the tube and the cap well before measuring
  • Check that there is no deformation of the tube that could distort the measurement
  • If in doubt, choose a cap that is slightly larger rather than too small

Conclusion

Precise measurement is essential for choosing the right plug. In case of doubt or if there is no exact match, a plastic plug with a slightly larger outside diameter (0.5 to 1.5mm) can be chosen to ensure a secure fit without the risk of slipping. By following these steps carefully, you will obtain the correct size of plug for your chair.