Measuring Coated Wire: Core and Finished Diameter

Two different measurements

A coated wire has a metal core and an outside dimension that includes its coating. Paper wrapping, PVC and lacquer are different constructions; the same core diameter does not imply the same finished diameter.

On an order, write the core diameter and finished diameter separately when both matter. State the tolerance required for each. A gauge number needs its system and measurement basis confirmed.

Use the right method

Use a suitable, calibrated measuring instrument and an agreed method. Take readings at more than one point and direction where roundness matters. Avoid crushing a soft covering with excessive force.

For paper-covered or textured wire, the outside measurement may vary around the surface. Agree whether the specified figure is a nominal overall size and how acceptance will be checked. An outside reading alone cannot establish the core diameter.

Flat and twisted profiles

For rectangular strip, identify thickness and width separately, such as 1 × 3 mm. For twisted wire, distinguish original strip dimensions from the outside envelope of the finished profile. These are not interchangeable inputs to a weight calculation.

Sending an enquiry

Include the product name, a drawing or sample if available, the dimensions that matter and the measurement basis. See wire gauge conversion and weight calculations.