Radius Charts
15° 30° 45° 60° 75° Angles

Radius Charts


All Charts and Screens Feature the Sealed Image Process

The Sealed-image process was developed to give maximum life to our precision charts and screens. A thin sheet vinyl plastic is laminated over the artwork, thereby protecting the image from wearing off due to use or cleaning.

The lines on charts are made accurate to their center unless otherwise stated on the chart. Our basic line width is .004" to .005" (.1-.12mm).

Glass screens are used for new or replacement screens for optical comparators. The image is centered to the OD of the glass to .005". Glass screens are available only for 14", 16", 24" and 30" S-T Industries, Inc./SCHERR-TUMICO optical comparators. Glass screens are recommended when the artwork pattern will be used for all application.

Plastic overlay charts are recommended when patterns will be changed frequently. Plastic charts are available in any diameter up to 30" (760mm). The plastic material is dimensionally stable, non-flammable and resistant to oil. To avoid distortion, plastic overlay charts should not be stored above 140°F (60°C).

Cleaning - Clean Sealed-image charts and screens with glass cleaner, soap and water or isopropanol using a soft cotton cloth. Avoid harsh rubbing. Do not use paper towels or coarse cloths and do not use acetone, benzene, lacquer thinner or other strong chemicals, as they will damage the surface.

To order glass and plastic charts, use this part number format:


Pattern Number
(Machine size, Inches)

(Glass=25, Plastic=30)
Example: 20X Radius/Grid Glass Screen for 14" Optical Comparator=74-0031-1425

Important - When ordering glass replacement screens, please include the model number and serial number of your optical comparator.

Special Artwork - Custom artwork is available on request. We can combine standard patterns or produce custom artwork scaled from your drawings.

NIST Certifications - Accuracy certifications can be provided at an additional charge. Please request this at the time your order is placed.


Catalog #Mag.Increments
74-0133 5x .010"
74-0100 10x .005"
74-0101 20x .0025"
74-0102 25x .002"
74-0103 31 1⁄4x .002"
74-0104 50x .001"
74-0105 62 1⁄2x .001"
74-0106 100x .0005"
74-0162 10x .10mm
74-0163 20x .05mm
74-0164 50x .02mm
74-0165 100x .01mm

Other magnifications and increments available on request.