BMG’s extensive range of fasteners, tools and related equipment is used to enhance reliability of equipment in diverse sectors, including light, medium and heavy industries, pulp and paper, construction, original equipment manufacturers and agriculture.
“BMG’s portfolio of over 15 000 locally manufactured and imported fastener stock items are available in a variety of grades, materials and strengths that meet stringent quality and safety specifications,” says Andrew Johns, manager, BMG’s fasteners, tools & equipment. “These fasteners are enhanced by products that prevent the loss of joint clamp and equally important are installation and disassembly tools that ensure each fastener is correctly installed and efficiently removed.
“For a fastener to be effective, key factors that require attention are the type of bolted joint design required and whether the joint should be serviceable or permanent. There are two types of joint for consideration – either tension joints or shear joints.
“Tension joints are simply explained by the tension created on the bolt and clamped components of the joint, by stretching the fastener when torque is applied during tightening. This torque needs to be accurately calculated to ensure that the fastener’s limits are not exceeded. Conversely, the application of insufficient torque and thus an ineffective clamp of components, could mean the joint will prematurely self-loosen.
“The second type of bolted joint uses the shear strength of the bolt to transmit the load and often relies on a locking mechanism to retain the joint integrity as opposed to a high clamp force.”
If a serviceable joint is required, a number of factors need to be considered to ensure that bolt-securing elements are effective and that the joint tension is maintained over the life of the joint. These factors include thread size, clamp length ratio, preload, amplitude, lubrication and surface quality.
The selection of appropriate assembly and loosening tools, coupled with accessibility to the joints, is critical to overcome factors that cause the loss of clamp and to ensure ease of assembly and disassembly.
Some of these products include Nord-Lock wedge locking washers, which when tested according to DIN 25201-4:2010-01, have a remaining joint clamp load of more than 80% after 2 000 cycles. Nord-Lock washers are available in standard, over-size and X-Series for softer materials or flexible joints, as well as Stainless Steel to combat corrosion.
BMG’s Nord-Lock bolt securing system uses tension instead of friction to ensure that joints holding sub-assemblies together remain secure. Bolts need to be easily removable during maintenance procedures, but must resist the loosening effects of vibrations and dynamic loads.
Bolts that are locked conventionally by friction between components tend to lose most of their preload through vibrations, while those locked by the tension of this system present a minor loss of preload which is caused mainly by settlement between contact surfaces. Even after moderate tightening, the bolt is safely locked when using Nord-Lock’s wedge-locking method.
Nord-Lock washers, which are installed in pairs, cam face to cam face, have cams between them, with a greater rise than the pitch of the bolt thread. When the bolt and/or nut is tightened, the radial teeth on the opposite side grip and seat the mating surfaces. The teeth also lock the washers in place, allowing movement only across the face of the cams. If the bolt or nut rotates loose in relation to the other, the resulting tension caused by a rise over the cams makes the bolt self-locking.
BMG’s Superbolt multi-jackbolt tensioners, which form part of the Nord-Lock range, are designed to reduce downtime and eliminate unsafe and laborious bolting methods for equipment, particularly in harsh operating conditions.
Advantages of this re-usable system include maximum safety when locking fasteners, easy assembly and disassembly, positive locking at low or high preload levels and minimum surface marring or scratching. This system, which has the same temperature characteristics as a standard bolt or nut, resists loosening caused by vibration and dynamic loads. The locking function is not lost by lubrication.
For a permanent, guaranteed clamp application, BMG recommends Huck structural rivets and lock bolt solutions and for extreme temperatures and challenging environments, the Thome and Schwind range of specialised fasteners is recommended.
Thome and Schwind high quality fasteners range from standard types, to stainless steel and special nickel alloy materials for use in extreme conditions
For high strength challenges, the Nord-Lock Superbolt multi-jackbolt tensioner system, with advanced bolting technology, only requires simple mechanical torque tools for installation, eliminating the need for high strength hydraulic torque tools.
To achieve the optimum clamp, BMG offers Gedore mechanical torque hand tools, as well as Atlas Copco and Ingersoll Rand pneumatic and electronic assembly tools, using clutch and transducer technology, to measure and control tightening torque. It is also possible to record all joint tightening procedures performed to ensure optimum clamp in safety and quality critical applications.
Other products include hand and power tools, tool kits, personal protective equipment, locks and lockouts, lifting equipment and environmental products. The range also encompasses measuring and testing equipment, welding and abrasives, as well as cutting and workshop equipment.
BMG’s network of over 120 branches offers a technical advisory and support service to ensure the correct product is selected for each specific application. The company’s advanced fastening solutions and installation tools are designed to meet the requirements of quality and safety critical installations, also ensuring the best total cost of ownership.
Huck Bobtail lockbolts offer up to 10 times the fatigue strength of conventional nuts and bolts and are suitable for heavy duty applications where ultimate vibration resistance is critical.