Pi Tape® Diameter Measuring Tapes
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The periphery tape. exemplified by Pi Tape® brand tape, provides a quick, accurate and easy method of reading true diameters of both round and out-of-round forms.
- Perfect for measurement of thin or soft walled parts - large
or small.
- Pi Tape gages consist of a narrow metal ribbon bearing special
graduations.
These graduations are designed to convert circumferential distance into diameter measurement so the observer can read the diameter directly from the scale.
- Tapes are checked over master gages at .001'"(.03mm)
accuracy for standard tapes up to 144" (3600mm).
Certificate of accuracy traceable to National Institute of Standards and Technology is furnished.
- Pi Tape gages are a precision tool made of 1095 clock spring
steel (on request 420 stainless steel - for use in a corrosive
atmosphere).
They require a minimum of maintenance, but we do recommend a quick wipe with an oil moistened cloth after use. A light gun oil works very well.
Make sure the tape has not been dented or kinked. This may
affect the accuracy of the tape.
Pi Tape gages are invaluable tools to the aero-space field as
well as the plastic pipe industry. The variety of uses are infinite.
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| Standard width is 1/4" gage member. 1/8, 3/8 or 1/2" widths also available - extra charge per tape. | Vernier scale divides each graduation on tape body into 25 parts or .001 of an inch |
| Example: | |
| In the illustration the divisions to the left of the Vernier zero are 20 inches plus 1 division, or 20.025. The 15th line on the Vernier coincides with a line on the Gage Member. This is added to the 20.025, making a total diameter reading of 20.040, which is the true diameter reading as measured on the outside circumference. When reading the tape, apply a snug pull of 5 lbs. tension, first making sure the tape and part have been properly cleaned. When using a standard O.D. tape on an I.D. surface, add double the tape thickness to the reading to arrive at the I.D. of the part (0 lbs. tension). It is suggested that direct I.D. tapes be used for Inside Diameter readings. | |
| Instructions on how to measure with Pi Tape® Inch Outside Diameter tapes on YouTube | |
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| Standard width is 6.35 mm gage member. 4.76, 9.53 or 12.70 mm widths also available - extra charge per tape | |
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Each line on the Gage Member of the tape represents
.5mm of Diameter, while each line on the Vernier represents .01mm.
The zero on the Vernier is past the 661.5 line on the Gage Member
of the tape. Now find the line on the Vernier which corresponds
exactly with the line above. The example shows it to be the 23
line which equals .23mm. This added to the 661.5 reading gives
an outside diameter of 661.73mm. As a suggestion for checking very large diameters-pieces of masking tape may be used to hold the tape in proper parallel position. |
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| Instructions on how to measure with Pi Tape® Metric Outside Diameter tapes on YouTube | |
Care
When not in use, wipe clean and apply a light rust preventive
oil. Store in tape container.
No periodic adjustments are needed.
Make sure the tape has not been stepped on or kinked, which may
destroy the accuracy.
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an economical alternative when an accuracy of .01 is an acceptable tolerance.