摘要:
When mapping out the internal cross-sectional dimensions of elongated, tubular bodies, correlated values of the external cross-sectional dimensions and wall thicknesses are measured along measuring lines from the outside of the body and the sum of the wall thicknesses measured along each measuring line is subtracted from the external cross-sectional dimension measured along the same or substantially the same measuring line. This avoids the use of measuring means in the interior of the tubular bodies, whereby the measuring can be carried out much faster and without the danger of injuring the internal surface of the bodies.