Tangless inserts save time in critical assembly
04 January 2013
Stainless steel fasteners are used in many applications where zero foreign object debris (FOD) is essential. Such applications include the food industry, clean rooms, electronics, aerospace, satellites, safety critical applications, space and other vacuum environments.
The tangless insert was developed to eliminate the potential problem of tangs being broken off after installation and being left behind, or ending up in critical parts of equipment.
Tangless Kato CoilThread inserts from Advanex have all the characteristics of tanged threaded inserts, without the need for tang break-off and retrieval; moreover, they are easily adjusted or removed after installation. This ensures significant time savings on each installation, especially in applications that usually require the counting of each removed tang.
Additional time savings are made because of the bi-directional design of tangless threaded inserts which avoids having to ensure that each part is correctly orientated, and the availability of special tools to speed installation. These benefits are obviously multiplied for high volume users.
All the benefits of Tangless Kato CoilThread Inserts from Advanex are now available in a variety of materials to provide a solution for all our customers’ application requirements. Our standard insert range, made from 304 stainless steel (AS7245), will meet most application requirements.
There is, however, a problem with stainless steel inserts when they are used with mating stainless steel fasteners: they can be susceptible to galling, a cold welding process which can occur when pressure builds between the contacting thread surfaces of male and female fasteners during assembly.
At the least this may cause some damage to thread forms or, in severe cases, prevent disassembly of the threaded joint. To lessen the effect of galling, some users apply lubrication before joint assembly. However, this can lead to unreliable torque/ tension results in the joint and also have FOD issues that may not be acceptable for a critical application.
For applications where galling or magnetic permeability is an issue, tangless inserts made from an anti-galling wear resistant austenitic stainless steel, comparable with materials like Nitronic 60 (UNS S21800) are available. The gall resistant stainless steel material has strength properties similar to the standard stainless steel material, providing galling prevention without the need for lubrication or plating.
Combining the benefits of a tangless insert with a special anti-galling material, customers with critical applications finally have a truly FOD free solution. This material is also non-magnetic and can be used in manufacturing facilities that have a vacuum process environment or equipment.
For high temperature (550oC) applications, tangless Inconel X750 inserts (AS7246) are now available. Inconel X750 is a non-magnetic, high corrosion resistance nickel based super-alloy with excellent heat resistance and strength characteristics. And for salt water and electrical applications, as long as you don’t need the strength of stainless steel or Inconel, tangless phosphor bronze inserts (PB102) are also available.
These Advanex Kato Precision products and associated tooling are available in the UK from ASM Fasteners.
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