Set No. 8 (Accessories for Angle Gauge Blocks)

A set of accessories for Soviet-manufactured prismatic angle gauge blocks (plane angle gauges), produced by the Chelyabinsk Tool Plant, in accordance with GOST 2875-75 / GOST 2875-88.

Purpose and Contents

This accessory set is used in metrology and mechanical engineering to assemble individual angle gauge blocks into a single rigid assembly. This allows for the precise inspection of both external and internal angles of components, templates, and tools.

Angle gauges (plane angle gauges) are designed for the inspection and calibration of angle-measuring instruments and angle templates, as well as for checking the angular dimensions of manufactured parts. The angle gauges feature mounting holes for attaching fixtures used to clamp the individual blocks together into assemblies.

The standard set includes:

- Clamping bars (4 pieces). Metal strips with slots, located on the left-hand side of the case (three of them are wrapped in oil-soaked paper in the photograph).
- Taper pins (5 pieces). Small pins inserted into the vertical slots in the upper-right section of the case to secure the gauge blocks.
- Profile straightedge. A long steel straightedge with a bevelled edge, stored in the lower longitudinal compartment.
- Screwdriver. A small screwdriver with a dark handle, used to tighten the fastening screws.
- Clamping blocks or additional fastening elements. Located in the lower-right corner and wrapped in oil-soaked paper.

Permissible Deviations of the Working Angles

The permissible deviations of the working angles of the plane angle gauges are:

- Grade 1: ±10 arcseconds
- Grade 2: ±30 arcseconds