I, Machine Shop Term Inside Diameter (ID) A measurement equal to the length of the longest straight line, perpendicular to internal surfaces, that fits inside a hollow cylinder; or the diameter of the inside of a tube, pipe, or other circular object. ◀Previous Term Next Term ▶
A measurement equal to the length of the longest straight line, perpendicular to internal surfaces, that fits inside a hollow cylinder; or the diameter of the inside of a tube, pipe, or other circular object.