Gauge block accessories

The use of gauge blocks for measuring can be extended by the use of a range of accessories. These are covered by BS 4311-2 2009. A typical set of gauge-block accessories is shown in Fig. 5.5 and consists of (1) two pairs of jaws, type A and type B, which when combined with gauge blocks form an external or internal caliper, Figs 5.6(a) and (b) a centre point and a scriber, used in combination with gauge blocks to scribe arcs of precise radius. Fig. 5.6(c) ... 

The use of gauge blocks for measuring can be extended by the use of a range of accessories. These are covered by BS 4311-2 2009. A typical set of gauge-block accessories is shown in Fig. 5.5 and consists of... 

Gauge blocks are also widely used in conjunction with sine bars and with calibrated steel balls and rollers, as well as for checking straightness and squareness. They are also used in conjunction with a range of accessories. 

The accessories other than the holders are made from high-quality steel, hardened and stabilised, with their wringing faces precision-lapped to give flamess, parallelism and surface finish to the same degree as gauge blocks, to which they are wrung to assemble any combination. Accessories can be purchased in sets as shown or as individual items. 

To obtain a specific size combination, gauge blocks can be inserted between the end of the length bar and the accessory. Two combinations of gauge blocks are required with any assembly, to fit between the accessory at either side of the connecting screw. 

There are many types of ATR accessory. The old-style versions are the fully demountable type, with the ATR element (IRE) mounted vertically (traditional). The more modern variants include the horizontal ATR and the cylindrical ATR (such as the Circle and Tunnel cells). The traditional accessory is suitable for studying continuous surfaces, such as sheets or small blocks of compliant materials, and today it has relatively limited application. The horizontal accessories are ideal for liquids and pastes (trough versions) as well as soft powders and sheet films (flat plate versions). If a powder or film is to be analyzed with a horizontal ATR, pressure must be applied. The accessories are normally supplied with an optional pressure applicator for this purpose often equipped with a micrometer gauge for reproducible setting of the applied pressure. The cylindrical ATR accessories are normally limited to mobile liquids. 

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