Scribing blocks

The surface gauge, also known as a scribing block, is used in conjunction with a scriber to mark out lines on the workpiece parallel with the reference surface. The height of the scriber is adjustable and is set in conjunction with a steel rule. The expected accuracy from this set up will be around 0.3 mm but with care this can be improved. 

When the biliary tract becomes blocked, bilirubin is not excreted and serum concentrations rise. The patient becomes jaundiced. The jaundiced patient is de.scribed further on pages 52-5.T. 

Clamp shaft in a vee block ensuring that the line marked at step 1 is lying horizontal. This can be checked using a scriber in a surface gauge. Transfer the centre line along the required length of shaft. Scribe two further lines to indicate the width of slot. 

The required length of slot can be marked without removing it simply by turning the vee block on its end and scribing a horizontal line at the correct distance from the end of the shaft. 

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) ... 

For each peptide to be cleaved, place a 4 ml glass collection vial scribed with the peptide code number in the collection rack in the lower chamber and carefully fit the block assembly together ensuring that the drain tubes enter all the vials. It is essential to scribe the tubes with a diamond pen as any writing with felt-tipped pen will be erased by the acid. 

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