Self-locking threaded fasteners assessed by institutions

According to tests undertaken by institutions such as MIT, the Goddard Space Flight Center and others, Spiralock's thread locking form outperforms standard fasteners in terms of resistance to vibration, axial-torsional loading, joint fatigue, and thermal extremes.

Engineers are successfully attacking vibrational loosening, axial-torsional loading, joint fatigue, and thermal extremes with Spiralock's innovative self-locking threaded fasteners whose effectiveness has been validated in published test studies at leading institutions including MIT, the Goddard Space Flight Center, Lawrence Livermore National Laboratory, and British Aerospace, as well as at noted corporations such as Mack Truck and Dana Corporation.

Resistance to vibration

Tests undertaken by the Goddard Space Flight Center subjected Spiralock nuts (stainless alloy A-286 and alloy steel) to vibration and static load conditions. The most severe vibration tests (sine: 24.7Hz - 2G and random 20-400Hz - 2G RMS) did not loosen the nuts when subjected to both high amplitude and sine random testing.

British Aerospace: Naval Warfare Division also confirmed Spiralock's self-locking threaded fasteners' resistance to vibration. Testing was performed on an Unbrako Fastener Vibration Machine using M6 x 25mm grade 8 bolts with wire inserts in L168 aluminum, and 20 samples of both Spiralock wire inserts and standard (60 degree UN thread) wire inserts. These were tested at 13.6Hz and tightened to 1800 pounds of preload.

Results showed that Spiralock wire inserts delivered consistent vibration-resistant performance with an average preload loss of 15 per cent, while the standard wire inserts gave erratic results, losing from 22 to 95 per cent preload given the same test parameters.

Resistance to axial-torsional loading

A finite element analysis (FES) report prepared for Lawrence Livermore National Laboratory compared a spacecraft node-to-strut threaded connection using 10-32 UNF-to-Spiralock female thread. In analysing axial thread load distribution, separate analyses were performed to compare the load distribution for each thread of Spiralock's self-locking fasteners and the UNF. The boundary condition on both nuts was changed to constrain the face of the nut in the axial direction, but free to move in the radial direction.

The report explains how the design of Spiralock's self-locking fasteners allows for more uniform load distribution on each thread: "The thread bearing stresses in the Spiralock threads are concentrated at the sharp points of contact where there is localised yielding in compression. These high local compressive stresses do not cause a strength problem, but the local yielding allows a more uniform load distribution on each thread."

Similar studies published in a report by the Massachusetts Institute of Technology (MIT) for Chrysler Corporation compares Spiralock's self-locking threaded fasteners (on the nut) and standard 60 degree thread forms.

According to the report, calculations show: the total bolt load is more evenly distributed over the engaged threads for Spiralock thread locking form than the 60 degree thread form; the maximum stresses at the root of the bolt thread are of the same order of magnitude in both cases; and the movement required for relative rotation is significantly higher for Spiralock.

Visit Spiralock's website for complete reports on the self locking threaded fasteners, including comparative graphic loading characteristics or photoelastic analysis/load vector comparison animation, as well as test data from Mack Truck and Dana Corporation about the thread locking form.

Stanley Engineered Fastening

Avdel UK
Stanley House, Works Road
Letchworth Garden City
SG6 1JY
UNITED KINGDOM

+44 (0)1582 900 000

enquiries2@sbdinc.com

https://www.stanleyengineeredfastening.com/

More technical articles
2 days ago
maxon is giving away a Swiss Army Knife every day in December
maxon has launched its 2023 Advent Calendar, giving away a classic Victorinox Swiss Army Knife every day in December until Christmas Eve. To enter maxon’s Advent Calendar, visit the maxon prize draw 2023 and click on the door for the corresponding day.
2 days ago
Yaskawa commits to UK with state-of-the-art facility
Yaskawa – a global technology supplier in segments drives, motion controls and robotics – is opening a new, state-of-the-art UK headquarters and manufacturing facility in Sunderland.
4 days ago
NSK bearings help pet food plant raise OEE
When a major UK pet food producer wanted better machine utilisation with the aim of raising its OEE (overall equipment effectiveness) by 3 points, it asked experts at bearing specialist NSK if they could evaluate processes and systems to help with this improvement goal.
5 days ago
Beckhoff UK and HepcoMotion’s mechatronics showcase takes centre stage
Automation technology specialist Beckhoff UK, in collaboration with leading manufacturer of linear motion systems, HepcoMotion, hosted a mechatronics showcase at MK7, the home of Oracle Red Bull Racing in Milton Keynes, with several innovations from both companies on display, as well as a brand-new product reveal – the GFX-r guidance system.
5 days ago
PPMA re-brand puts automation at the heart of UK manufacturing
The PPMA Group of Associations has re-branded and has changed its name to AutomateUK to better represent the needs of its membership and their end user customers in the ever-changing manufacturing landscape.
1 day ago
steute Technologies restructures its business fields
steute Technologies, an international technology company offering switches, intelligent sensors and wireless systems, has announced a comprehensive restructuring of its business fields.
1 day ago
Showcasing design, production and process engineering in the food and drink sect
Taking place on 1 May 2024 at the National Motorcycle Museum, Food Manufacturing Live serves the design, production, process and maintenance engineering teams across the UK food and drink manufacturing sector.
2 days ago
Understanding safety and security for the protection of human and machine
How do you master employee protection, liability protection, productivity and data protection? How do you increase your quality and simultaneously prevent manipulation on your machines? How do you protect your data and employees in equal measure? Pilz is hosting a free webinar on 15 December, 9:30-10:30 am, to address just these questions.
2 days ago
Schaffner opens new regional channels for its range of EMC solutions
EMC solutions provider, Schaffner, announces new partnerships with three distributors to further broaden the reach and scope of its product range and support services across Europe. The new agreements with Telerex, CATS and DSL Components will open new supplier corridors and enable customers to have local and faster access to products.
2 days ago
New SCARA robot transforms pick-and-place and assembly operations
ABB Robotics is expanding its industrial SCARA robot portfolio with the addition of the IRB 930. The new robot, compromising three variants capable of handling 12 kg and 22 kg payloads, has been designed to meet the demands of new growth opportunities in traditional and new markets.

Login / Sign up