Mitutoyo 137-212 Inside Micrometer, 2 - 12" Extension Rod

The Mitutoyo 137-212 is an extension rod inside micrometer that measures inside diameters from 2 to 12". You screw extension rods onto the micrometer head to reach the size you need, and the rods are spring-mounted in protective sleeves. Toolrooms, quality control teams and machinists use it to check bores, cylinders and gaps in inches.

It reads to a graduation of .001" with a 0.5" measuring span, and has hardened steel measuring faces. Graduation is the smallest step marked on the scale. Accuracy is a separate figure: it is the biggest error Mitutoyo allows, so do not read a fine graduation as a promise of that accuracy. Five extension rods, a spanner and the 137-012 micrometer head come in the box. A carbide-tipped version is sold under another code.

Where this product is used

• Measuring bores, cylinders and gaps from 2 to 12"
• Toolroom and quality control inspection of inside diameters
• Machine shop checks in inches

Features

• Measures inside diameters from 2 to 12"
• Graduation of .001" with a measuring span of 0.5"
• Hardened steel measuring faces, 2-point measuring method
• Five extension rods: 0.5, 1, 2 (2 pcs.) and 4"
• Rods are spring-mounted in protective sleeves
• Spindle feed error of 0.00015 inch
• Supplied with a box, a spanner and the 137-012 micrometer head
• Weighs 305 g

Key specifications