croblox® Optical Polygons
Webber Optical Polygons provide an easy, accurate method of checking and calibrating angles. They are designed for use with autocollimators in measuring angle spacing. The exclusive one-piece design provides a compact, fixed master for precise angle spacing. Other applications include use as an optical element in laser or optical scanning systems.
Target faces are highly reflective and optically flat. Webber croblox (chrome carbide) polygons provide a hardness of Rockwell 71-73 C and a corrosion resistance 10 to 20 times that of 18-8 stainless steel, resulting in lifetime accuracy.

Maintenance problems are virtually eliminated due to their ruggedness and extreme stability.

Each face is .75" x .75" (19mm x 19mm). A 1" mounting hole, flanged bushing, lapped washer and hold down bolt, furnished with each unit, permit mounting the polygon in any desired attitude. Optical polygons are available in two accuracy grades and may be obtained with up to 12 faces. Polygons are furnished in a case with a Certificate of Calibration.

To order polygons, specify the part number in the following sequence:

Optical Polygon OP
Number of Faces
Decimal Point
Accuracy Grade
Example: OP 3.0 = A 3 sided polygon with a 0 Reference Accuracy
Accuracy Grade Target Area Flatness Uncertainty Max. Deviation of Faces from Nominal
Reference: 0 4 µin. (0.1 µm) ±1.0 sec. ±1.0 sec.
Calibration: 1 4 µin. (0.1 µm) ±1.0 sec. ±2.0 sec.
©2011, Webber Gage Division, The L. S. Starrett Co, Cleveland, Ohio , 44145