Standard

BS 959:2008

Specification for internal micrometers (including stick micrometers)

Current

•

Published:

30 Nov 2008

1 Scope

This standard specifies requirements for internal micrometers comprising a measuring head, extension rods with or without spacing collars, and, in the smaller sizes, a handle.

Provision is made for three sizes of measuring heads, in both metric and inch units, as shown in Table 1 and Table 2.

NOTE Attention is drawn to the fact that metric dimensions are not necessarily direct conversions of the imperial dimensions.

Table 1 — Measuring heads — metric measurements

Size of head	Length of graduated scale on barrel	Usual ranges of the instrument when used with extension rods
Size of head	mm	mm
Size 1	5 or 6.5	25-50
Size 2	10 or 13	50-150
		50-200
		50-300
Size 3	25	200+

Table 2 — Measuring heads — inch measurements

Size of head	Length of graduated scale on barrel	Usual ranges of the instrument when used with extension rods
Size of head	in	in
Size 1	¼	1-2
Size 2	½ or 1	2-6
		2-8
		2-12
Size 3	1	8+

This standard also covers stick micrometers, which are designed for the measurement of longer internal lengths, and comprise the following parts:

a) a 150 mm or 300 mm or 6 in or 12 in micrometer unit, fitted with a micrometer of 25 mm or 1 in range, and having rounded terminal faces;
b) a series of extension rods which, together with the micrometer unit, permit a continuous range of measurement up to the maximum length required.

Annex A gives a method of test for the accuracy of internal micrometer readings.

Product Details

Descriptors

Gauges

Rigidity

Linear measuring instruments

Dimensional tolerances

Micrometers

Internal

Graduations

Mechanical testing

Marking

Linear measurement

Precision

Accuracy

ICS Codes

17.040.30 Measuring instruments

Committee

TPR/1

International relationships

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ISBN

978 0 580 84673 1

Publisher

BSI