How to Measure O-Rings
- 1). Place the O-ring on a clean, flat, level surface.
- 2). Determine the outer diameter. Use a ruler to measure the outside diameter of the O-ring from one outside edge to another. Take this measurement in millimeters.
- 3). Measure thickness. Place the O-ring into a vernier caliper, oriented lengthwise. Lightly clamp the jaws of the caliper onto the O-ring, but do not compress it. Record the thickness.
- 4). Determine the inner diameter. Measure the O-ring from inside edge to inside edge or subtract twice the thickness of the O-ring from the outside diameter measurement.
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