BS/EN 4852-2019 pdf download.Aerospace series – External spiral drive heads for threaded fasteners – Geometrical definition and fastener head wrenching configuration.
This BS/EN 4852 specifies dimensions and gauging system for external MORTORQ super bolt head spiral drive system1.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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.
ISO 1101, Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form, orientation, location and run-out
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http://www.iso.org/obp
— I EC Electropedia: available at http://www.electropedia.org/
4 Required characteristics: Configuration — Dimensions — Tolerances
Configuration shall be in accordance with Figure 1.
Dimensions and tolerances shall conform with Figure 1 and Table 1 and are expressed in millimetres.
6 Configuration gauging
6.1 Types of gauge
Two varieties of gauges for acceptance inspection purposes should be used to gauge the bolt head, the
GO and NO-GO ring gauges as shown in Figure 2, wIth the dimensions shown In Table 2 and the
Fallaway gauges as shown in Figure 3. with the dimensions shown in Table 3a and Table 3b.
6.1.1 GO Ring gauge
Using light finger pressure only, place the bolt head into the appropriate GO gauge until resistance is
felt. Failure to bottom the bolt head into the gauge shall be cause for rejection.
6.1.2 NO-GO Ring gauge
Using light finger pressure only, attempt to place two opposing roots of the bolt head into the appropriate
NO-GO gauge until resistance is felt. Rotate the bolt head one tooth (600) and try again. Repeat a third time to ensure that all the minor diameters of the bolt head are within specification.
6.1.3 Fallaway gauge
Fallaway is a condition whereby the material of the bolt head does not completely conform to the shape
of the tool that produced it.
6.1.4 Fallaway root step GO-gauge
Using light finger pressure only, place two opposing roots of the bolt head into the appropriate Root GO-gauge. Failure to bottom the bolt head into the gauge shall be cause for rejection. Rotate the bolt head and check all three opposing roots for fit. The head of the bolt must also extend beyond the first step (height K) of the gauge to ensure that the minimum drive length is achieved.
6.1.5 Fallaway cylindrical GO-gauge
Using light finger pressure only, place the bolt head into the appropriate cylindrical GO-gauge. Failure to bottom the bolt head into the gauge shall be cause for rejection.
6.1.6 Fallaway cylindrical step gauge
Using light finger pressure only, place the bolt head through the bottom of the appropriate cylindrical step gauge. The part will be rejected if the top of the bolt head extends beyond the top surface of the gauge.BS/EN 4852-2019 pdf download.