IS 15631 : 2025/ISO 7436 : 2024 Fasteners - Slotted Set Screws with Cup Point - Specification
NATIONAL FOREWORD
This Indian Standard (First Revision) which is identical to ISO 7436 : 2024 'Fasteners - Slotted set screws with cup point' issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of General Engineering and Fasteners Standards Sectional Committee and approval of the Production and General Engineering Division Council.
Set screws also known as blind screws, are fasteners that consist entirely of a threaded rod. They do not have a head or a tip. Instead, they consist of a rod with uniform threading running the entire length of the screw. Set screws have several applications, one of the most common being to join two parts together. Assuming two parts have threaded holes in the appropriate size, they can be joined with a set screw. Half of the set screw is inserted into one of the parts, and the other half is inserted into the opposite part. The set screw will then join the two parts together while ensuring that they are flush.
Set screws can often prove especially useful in situations where a standard nut and bolt would impede the optimal functioning of an object or components, or else would not achieve the clean aesthetic the installer is aiming for on the visible/external faces of an item. They are almost always found being used in mechanical systems where two or more metal surfaces rub or press directly together, and where there isn't room to fit a bolt or other type of protruding head between the two flush surfaces without limiting proper functionality or movement of the parts. Common specific examples of set screw use include affixing spindle cams and handles or securing gears and pulleys to a shaft.
This standard covers the requirements of slotted set screws with cup point. The other standards on slotted screws are as follows:
a) IS 15628 : 2005 Slotted set screws with flat point;
b) IS 15629 : 2025 Slotted set screws with cone point; and
c) IS 15630 : 2005 Slotted set screws with long dog point.
This standard was first published in 2005. This revision has been brought out to align it with ISO 7436 : 2024.
The major changes in this revision are as follows:
a) For M3, l = 4 mm has been classified as regular standard length with lnom calculated in order to get at least 4 full pitches and short standard lengths lnom have been calculated in order to get at least 2.5 full pitches;
b) For stainless steel screw, Grades A2 and A4 with hardness classes 12H and 21H have been added;
c) Non-ferrous metal screws have been deleted (as a consequence of the withdrawal of ISO 8839);
d) For steel fasteners, 'plain' has been changed to 'as processed' in Table 3;
e) For stainless steel fasteners, 'plain' has been changed to 'clean and bright', and 'passivated' has been added in Table 3;
f) The requirement of surface integrity has been added for steel screws in Table 3; and
g) Specifications for marking and labelling have been added as 6.
The text of ISO standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:
a) Wherever the words 'International Standard' appear referring to this standard, they should be read as 'Indian Standard'; and
b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice is to use a point (.) as the decimal marker.