I recently received an interesting LI inquiry that I felt others could learn from the answers that I was able to get. This is not my expertise so I sought out answers from some colleagues who were more familiar with fasteners.
You can find more information on our web, so please take a look.
Here is the original inquiry (translated from Portuguese so I hope Google Translator did a good job):
“I would like to know if you can help me clarify my doubts about:
I first checked with our Ron Hughes (Sr. Reliability Consultant at Reliability Center, Inc):
“This is an excellent question as these highly engineered mechanical assemblies are often put in by “rule-of-thumb” rather than the slide rule mentality for which they are designed.
Mechanical fastener assemblies have been studied by the nuclear power industry for years and the derived coefficient of friction for the threads of these assemblies has indeed provided much needed quality assurance on safety related items. Testing in accordance with recommended ASTM and SAE standards is the quality control portion of the quality assurance program and is dome by the manufacturer of the fasteners. The ASME has worked closely with ASTM and SAE for decades on this program and many documents have been written on the subject.
The purpose is quite simple, what you are actually measuring is the slip resistance of the faying (contact) surfaces of the components being assembled. Torque ensures that the assembly is tensioned enough to maintain an adequate slip resistance. For steel bolts the general rule is that for every 0.001″ of stretch (tension) you put on a bolt you increase the clamping force (and thus the slip resistance) by approximately 3,000 psi of internal tension in the bolt.
Always remember that the coefficients are for new bolt threads that are non-lubricated and have never been previously tensioned (this changes the coefficients significantly). Field verification is done by proper torquing operations and by measuring break-away- torque when necessary.
It is good to remember that the torque values change after assembly. The initial assembly is the pre-load and the working load (or actual load) is only seen during operations. Some mechanical fastener assemblies will loosen and some tighten during working load.
The installer is responsible for making sure that the assembly has been made properly and the proper slip resistance has been achieved. Things to consider are as follows:
I then checked with a valued friend and colleague, Allan McNally (turbo-machinery expert currently working as a contractor in KSA):
1.0 The lubricant manufacturer typically provides the coefficient of friction stating a temperature range and various loads applications. I am going to assume the manufacturer does research and testing of the lubrication under various conditions following different controlled tightening procedures since they are willing to provide such information.
2.0 The only standards that I know about in relation to fasteners and torque/clamping force results (using lubricants as inputs in the testing process) include VDI 2230 and ISO 16047. However, both standards have specific definitions as to when they can be used.
3.0 Surface treatments CAN influence the results as the asperities for different materials create different lubrication boundaries.
4.0 I am not sure who is responsible for such testing, but in my experience equipment manufacturers typically provide a list of preferred lubricants to be used on equipment that must have bolted joints based on given conditions; therefore, I am assuming testing is done in the design and prototype faces to determine what lubricant provides the best results. The lubricant has various roles besides power transmission therefore the test may vary in each individual case.
5.0 The book (https://www.amazon.com/Introduction-Design-Behavior-Mechanical-Engineering/dp/0824792971) is an excellent source that helps understand joint design and the various factors that affect the design. I would refer those interested to this book as I haven’t found nothing better in the market. I once used the book to solve a failure and sure enough it helped a lot (solved the problem and the OEM paid for the damage).
For the other experts that are reading these responses, please chime in with your expertise so we can provide interested readers as much accurate info as possible.
I hate to let this great information go to waste by not letting as many people as possible learn from it!!!
Ordering friction bolts is a crucial step in ensuring the stability and safety of various applications, such as mining, tunneling, and ground support. To make informed decisions and choose the right friction bolts for your specific needs, consider asking the following key questions when placing an order:
Determine the appropriate bolt diameter and length based on the specific requirements of your project. Consider factors such as rock type, load-bearing capacity, and the thickness of the material you need to secure.
Ask about the material options for friction bolts, such as steel or fiberglass, and inquire about available coating options. Coatings like galvanized or epoxy can enhance corrosion resistance, crucial for bolts used in challenging environments.
Understanding the load capacity of the friction bolts is essential for ensuring they can handle the expected loads in your application. Consider factors like ground conditions and the magnitude of the forces the bolts will be subjected to.
TRM supply professional and honest service.
Friction Bolt and Split Set Utility Hanger Bolt
For specific applications or challenging conditions, inquire about specialty bolts designed for unique situations. Examples include split set bolts for difficult ground conditions or corrosion-resistant bolts for harsh environments.
Ask about the installation process for the friction bolts. Understand whether special tools or equipment are required and inquire about any recommended procedures to ensure proper and efficient installation.
Check if the friction bolts meet industry standards and certifications. Compliance with relevant safety and quality standards ensures that the bolts are suitable for use in regulated environments and meet required performance criteria.
Obtain a detailed quote that includes the cost of the friction bolts, any additional accessories, and the expected delivery time. Consider the overall value and reliability of the supplier when assessing costs.
47mm Friction Bolt Split Set Stabilizer
Ask if technical support or assistance is available from the supplier. Having access to experts who can provide guidance on selecting the right friction bolts and addressing any installation challenges can be invaluable.
Q: Can friction bolts be used in different ground conditions?
A: Yes, friction bolts are designed for various ground conditions, and specialty bolts are available for challenging situations, such as unstable rock formations.
Q: Are there specific safety guidelines for installing friction bolts?
A: Yes, it's important to follow safety guidelines and recommended installation procedures provided by the manufacturer to ensure proper and secure installation.
Q: Can I get customized friction bolts for specific project requirements?
A: Some suppliers offer customization options for friction bolts, allowing you to tailor the bolts to meet the specific requirements of your project.
Tanrimine Metal Support Co.,Ltd (TRM) is a professional manufacturer for Friction Bolt Split Set and Plate, as well as a full range of its accessories and relative components. If you are looking for professional customized friction bolts, click here.
I recently received an interesting LI inquiry that I felt others could learn from the answers that I was able to get. This is not my expertise so I sought out answers from some colleagues who were more familiar with fasteners.
Here is the original inquiry (translated from Portuguese so I hope Google Translator did a good job):
“I would like to know if you can help me clarify my doubts about:
I first checked with our Ron Hughes (Sr. Reliability Consultant at Reliability Center, Inc):
“This is an excellent question as these highly engineered mechanical assemblies are often put in by “rule-of-thumb” rather than the slide rule mentality for which they are designed.
Mechanical fastener assemblies have been studied by the nuclear power industry for years and the derived coefficient of friction for the threads of these assemblies has indeed provided much needed quality assurance on safety related items. Testing in accordance with recommended ASTM and SAE standards is the quality control portion of the quality assurance program and is dome by the manufacturer of the fasteners. The ASME has worked closely with ASTM and SAE for decades on this program and many documents have been written on the subject.
The purpose is quite simple, what you are actually measuring is the slip resistance of the faying (contact) surfaces of the components being assembled. Torque ensures that the assembly is tensioned enough to maintain an adequate slip resistance. For steel bolts the general rule is that for every 0.001″ of stretch (tension) you put on a bolt you increase the clamping force (and thus the slip resistance) by approximately 3,000 psi of internal tension in the bolt.
Always remember that the coefficients are for new bolt threads that are non-lubricated and have never been previously tensioned (this changes the coefficients significantly). Field verification is done by proper torquing operations and by measuring break-away- torque when necessary.
It is good to remember that the torque values change after assembly. The initial assembly is the pre-load and the working load (or actual load) is only seen during operations. Some mechanical fastener assemblies will loosen and some tighten during working load.
The installer is responsible for making sure that the assembly has been made properly and the proper slip resistance has been achieved. Things to consider are as follows:
I then checked with a valued friend and colleague, Allan McNally (turbo-machinery expert currently working as a contractor in KSA):
1.0 The lubricant manufacturer typically provides the coefficient of friction stating a temperature range and various loads applications. I am going to assume the manufacturer does research and testing of the lubrication under various conditions following different controlled tightening procedures since they are willing to provide such information.
2.0 The only standards that I know about in relation to fasteners and torque/clamping force results (using lubricants as inputs in the testing process) include VDI 2230 and ISO 16047. However, both standards have specific definitions as to when they can be used.
3.0 Surface treatments CAN influence the results as the asperities for different materials create different lubrication boundaries.
4.0 I am not sure who is responsible for such testing, but in my experience equipment manufacturers typically provide a list of preferred lubricants to be used on equipment that must have bolted joints based on given conditions; therefore, I am assuming testing is done in the design and prototype faces to determine what lubricant provides the best results. The lubricant has various roles besides power transmission therefore the test may vary in each individual case.
5.0 The book (https://www.amazon.com/Introduction-Design-Behavior-Mechanical-Engineering/dp/0824792971) is an excellent source that helps understand joint design and the various factors that affect the design. I would refer those interested to this book as I haven’t found nothing better in the market. I once used the book to solve a failure and sure enough it helped a lot (solved the problem and the OEM paid for the damage).
For the other experts that are reading these responses, please chime in with your expertise so we can provide interested readers as much accurate info as possible.
I hate to let this great information go to waste by not letting as many people as possible learn from it!!!
Ordering friction bolts is a crucial step in ensuring the stability and safety of various applications, such as mining, tunneling, and ground support. To make informed decisions and choose the right friction bolts for your specific needs, consider asking the following key questions when placing an order:
Determine the appropriate bolt diameter and length based on the specific requirements of your project. Consider factors such as rock type, load-bearing capacity, and the thickness of the material you need to secure.
Ask about the material options for friction bolts, such as steel or fiberglass, and inquire about available coating options. Coatings like galvanized or epoxy can enhance corrosion resistance, crucial for bolts used in challenging environments.
Understanding the load capacity of the friction bolts is essential for ensuring they can handle the expected loads in your application. Consider factors like ground conditions and the magnitude of the forces the bolts will be subjected to.
Friction Bolt and Split Set Utility Hanger Bolt
For specific applications or challenging conditions, inquire about specialty bolts designed for unique situations. Examples include split set bolts for difficult ground conditions or corrosion-resistant bolts for harsh environments.
Ask about the installation process for the friction bolts. Understand whether special tools or equipment are required and inquire about any recommended procedures to ensure proper and efficient installation.
Check if the friction bolts meet industry standards and certifications. Compliance with relevant safety and quality standards ensures that the bolts are suitable for use in regulated environments and meet required performance criteria.
Obtain a detailed quote that includes the cost of the friction bolts, any additional accessories, and the expected delivery time. Consider the overall value and reliability of the supplier when assessing costs.
47mm Friction Bolt Split Set Stabilizer
Ask if technical support or assistance is available from the supplier. Having access to experts who can provide guidance on selecting the right friction bolts and addressing any installation challenges can be invaluable.
Q: Can friction bolts be used in different ground conditions?
A: Yes, friction bolts are designed for various ground conditions, and specialty bolts are available for challenging situations, such as unstable rock formations.
Q: Are there specific safety guidelines for installing friction bolts?
A: Yes, it's important to follow safety guidelines and recommended installation procedures provided by the manufacturer to ensure proper and secure installation.
Q: Can I get customized friction bolts for specific project requirements?
A: Some suppliers offer customization options for friction bolts, allowing you to tailor the bolts to meet the specific requirements of your project.
Tanrimine Metal Support Co.,Ltd (TRM) is a professional manufacturer for Friction Bolt Split Set and Plate, as well as a full range of its accessories and relative components. If you are looking for professional customized friction bolts, click here.