EDITOR ’ S CHOICE LOCKBOLTS ®
STAR FASTENERS
Consistent joint performance
WHAT ARE THEY AND HOW DO THEY WORK ? HuckBolts ®, also known as LockBolts are neither a threaded bolt or a rivet , but combine the desirable features of both . They have been used in many critical joint applications for decades , including widespread usage in demanding highstress , high-vibration environments . Industries using HuckBolts include heavyduty trucks , commercial vehicles , their chassis and trailers , rail track , crossings , railcar and locomotives , agricultural equipment and implements , aerospace , mining shaker screens and shaft construction , defence vehicles and oilfield equipment – some really challenging environmental conditions .
Terminology
LOCKBOLT INSTALLATION SEQUENCE
Often the most vulnerable point on a design is where there is an interface or join between components ; the availability of carbon steel , aluminium , and stainlesssteel variations make LockBolts fasteners a viable option for joining a multitude of material . HuckBolts can be effectively used with virtually any metal , and dissimilar metals with dissimilar coefficients of thermal expansion present no problems . Varying material thicknesses in a joint are readily accommodated , and surface finishes are not damaged .
HuckBolts such as C6L ® and C50L ® have been on the market for many decades and are well known and used . Others such as the Huck BobTail ® are less well known but offer significant advantages ; up to 10 times the fatigue strength of conventional nuts and bolts , they deliver ultimate strength , installation speed and vibration resistance .
The pintail-less design of the BobTail has been developed to deliver the highest levels of performance and reliability . BobTail LockBolts offer safe , quiet installation technology in an advanced HuckBolt design . There is no waste through break off of the pintail and corrosion performance
Terminology
is significantly improved by eliminating the exposed surface resulting from a pintail break-off . BobTail also has a fit-up function where the collar can be pre-fitted over the pin using helical grooves , allowing
Huck Lockbolt Range - for friction grip joints
to form the installed fastener providing a permanent and completely vibration resistant joint .
1 . Pin placed into prepared Once installed hole , the - Collar fastener placed will perform over pin the fasteners to be positioned without consistently for the lifetime of the joint the possibility of collar movement 2 . Tool . This
placed over the fastener pintail and activated allows projects to be lined-up obefore Pin final head pulled against material installation . o Anvil pushes PREPARATION collar against joint OF MATERIAL o Initial clamp generated FOR HUCK LOCKBOLTS AND
HOW DO LOCKBOLTS WORK ?
RECOMMENDED DRILLING LockBolts consist of a headed 3 . Tool pin and swages a collar PROCEDURE , increasing : - clamp collar that is swaged over locking grooves To get a positive , ridged , fatigue-resistant in the pin . The pin is made 4 with . Pintail a series breaks , installation joint to withstand complete vibration and reversals of pulling grooves at its tail end . The of stress good work-piece preparation is
installation tool ( driven by pneumatic , recommended . The hole should be round hydraulic or battery power ) grips these ( drilled , pre-punched or lazered ) and within grooves , pulls the work together , the conical tolerance of the recommended hole size shaped cavity of the nose assembly is specified by the data sheet . To prevent swarf and debris lodging between them , the forced down the collar . This progressively sheets should ideally be clamped together cold forms ( swages ) it into the grooves while drilling . of the harder pin . The squeezing action reduces the diameter of the collar ,
1 . Pre-drill – using a drill slightly smaller in increasing its length 1 . This Pin in placed turn stretches into prepared diameter hole to - the Collar required placed hole size over . pin the pin , generating a clamp force over the joint . The pin and swaged
2 . Tool collar is placed combine over the
2 . Size-drill fastener
– to pintail
LockBolt and hole activated diameter . o Pin head pulled against material o Anvil pushes collar against joint o Initial clamp generated
LOCKBOLT INSTALLATION without requiring checking SEQUENCE or retorquing .
3 . Tool swages collar , increasing clamp
BobTail ® C50L ® Hucktainer ®
Magna-Grip ®
4 . Pintail breaks , installation complete
32 PECM Issue 55
C6L / C120L ®