BS 957:2008 pdf download.Specification for feeler gauges.
1 Scope This British Standard specifies requirements for feeler gauges, comprising a series of gauging blades (blades) of graded thicknesses assembled in a protective sheath or supplied individually. These include requirements for dimensions which are expressed in metric and inch units. This standard is applicable to blades of thicknesses:
• from 0.03 mm to 1.00 mm inclusive (metric units); and
• from 0.001 5 in to 0.025 in inclusive (inch units).
2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. BS EN ISO 6507, Metallic materials – Vickers hardness test
3 General The purchaser shall state in his enquiry and order the particular combination of blades and length of blades required. NOTE Recommendations regarding suitable combinations of blades are given in Annex A.
4 Material of blades
4.1 The blades shall be made of good quality steel and shall be hardened and tempered to a hardness of not less than 400 HV nor more than 600 HV 1) . NOTE Consideration should be given to the corrosion resistance and toughness of steel used.
4.2 Blades shall be tested for hardness in accordance with BS EN ISO 6507 as shown in Table 1 and Table 2.
4.3 Blades of thicknesses less than 0.5 mm and 0.005 in shall be subjected to a scratch comparison test whereby the blade shall be placed on a hard, polished surface and scratched with a diamond tipped or hard steel stylus which has a tip radius of approximately 0.6 mm (0.02 in). The mark produced shall then be compared with a similar mark produced on a steel test piece of known hardness in the range 400–450 HV. The mark shall be made in the same manner and using the same force on both the blade and the test piece.
6 Finish The blades, throughout, shall be free from sharp edges. The blade surfaces and edges shall be free from deformations and have a smooth finish.
7 Accuracy The mean thickness of a blade shall not depart from its nominal thickness by more than the amount given in Table 3, Column 2 or Table 4, Column 2. Any local variation in the thickness of a blade shall not exceed the amount given in Table 3, Column 3 or Table 4, Column 3.
8 Sheath When the blades are fitted in a sheath they shall hinge smoothly and be adequately protected when folded into the sheath. The design of the hinge shall preferably facilitate the removal or replacement of blades.BS 957 pdf download.