Newman Tool Precision Steel Diameter Tape

A wide variety of Newman Tool Precision Steel Diameter tapes are available to meet specific diameter measuring needs.  Our smallest diameter measuring tape measures diameters from .50” – 4.0”  and our largest standard tape measures diameters from 144” – 156”. Larger tapes and metric sizes are available on a special order basis.  Tapes with Long Form NIST certificates are also available at an additional cost (factory certificates traceable to NIST are supplied at no additional charge).

Diameter tapes consist of 2 elements. A Gage member, and a Vernier member.  All Gage members with the exception our 2 smaller tapes are approximately 48” long with 38 inches of engraved main scale (12” x 3.141592). The Vernier is about 6" to 8” long and contains the engraved Vernier scale.  Diameter measurements are made by measuring the periphery of the object and matching the main scale to the Vernier scale.  The Gage member and the Vernier member are offset so that the tape can be positioned exactly parallel to the object being measured to take an accurate measurement. The accuracy of our tapes are certified to be within +/- .001”.  Both the Vernier member and the offset Gage member are 1/4” wide. Material thickness is .006" for the small tapes and .010" for the larger tapes.

All tapes are made from an advanced Stainless Steel Alloy that has physical properties similar to #1095 steel. All tapes are manufactured with processes that are non-aggressive to the metal.  No heat, chemicals, or other toxic materials are used thereby insuring the integrity of the tape. All tapes are temperature stabilized before the precision engraving of the gradients.  The engraving is done in a controlled environment at 68F and 45% humidity.

All tapes come with a lifetime warranty against breakage in normal use and material defects affecting the ability of the tapes to be recalibrated to specifications.  These products are shipped from Canada by FedEx; typical charges are about $25.00 per shipment.

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Instructions for use:

Precision Diameter Tapes are made from a single piece of stainless alloy. The material is cut in one piece using non aggressive methods creating two tape sections. The first is the Gage member, and the second is the Vernier member.



The curved transition from the Vernier to the Gage member allows each member of the tape to be matched together without overlapping. This gives the greatest degree of measuring accuracy.

To accurately use the tape, clean both the object being measured and the tape. Wrap the tape around the object and align the Vernier gradients along side of the Gage member gradients. To read a precise measurement, apply a tension of 5 lbs. (2.25 kg.) to the tape by pulling the knob on the end of tape. For the most accurate reading use a calibrated tension scale.



Accurately reading a precision diameter tape is simple and straight forward. In the illustration above, assume the tape has been stretched around a pipe that is approximately 42” in diameter, and the proper 5 lbs. of pull has been put on the tape. Start by reading the first dimension to the left of the “0” on the Vernier member. In the example we have 42.125. Next, find the gradients that line up exactly between the Gage member and the Vernier member. Read the number on the Vernier scale. In this example the number is 17. Add this extension to the 42.125 to arrive at the exact measurement of 42.142.

Metric tapes are graduated in millimeters with each gradient being .5 mm. On the Vernier scale each gradient represents .01 mm. Readings are taken the same as the illustration above.

For measuring very large diameter objects, assistance should be requested, or the measuring tape should be secured by means of masking tape to assure a parallel measurement