Precision Inside Diameter Tapes

Example:

Make certain the tape and object to be measured are both clean.
Each line on the gage member represents .5mm of diameter, while each line on the vernier
represents .01mm.
Place the tape inside the object to be measured. The vernier scale should be just below the gage member. Make
certain the tape is aligned on the inside diameter flat and snug to the part, straight and parallel so the gage
member is flat against the vernier scale.
Locate the “zero” on the vernier scale and note the highest value achieved on the gage member above it (the
highest value to the left of the zero). In this example, the value is 660.0mm.
Next, observe the vernier scale’s value at the point where it lines up exactly with a marked division line on the
gage member. In this example, the value is 23 (0.23mm).
Finally, to obtain the diameter of the object, simply add the two values together:
660.0mm + 0.23mm = 660.23mm
Inside diameter tapes are manufactured at 68ºF under no tension. All inside diameter tapes are marked I.D. and
are calibrated for direct inside diameter readings.
As a suggestion for checking very large diameters – pieces of masking tape can be used to hold the tape in the
proper parallel position.
Tape resolution 0.01mm