THE TOOL NOTEBOOK
Read a pottery measuring specification
Identify the measurement being made
A caliper may transfer an inside or outside dimension, while a thickness gauge or ruler serves a different task. Check the measuring faces and units on the exact model. Overall tool length does not automatically equal its measuring range. A photo with open jaws also does not establish a maximum supported measurement unless the source documents that limit.
Graduations are not verified accuracy
A smaller marked division or displayed increment is not proof of accuracy to that amount. Read the stated range and graduation separately, and do not invent a calibration claim from a precise-looking scale. For shrinkage rulers, check the labeled basis rather than applying one universal shrinkage factor. Your clay and process cannot be inferred from the ruler’s appearance.
Compare like with like
Shortlist tools that measure the same kind of dimension before comparing size or price. Record the units, measuring surfaces, included pieces and any documented limits. A layout or center-finding tool helps with positioning but does not guarantee wheel centering or fit. Use the exact manufacturer instructions and verify the measurements needed for your own project.