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Fastener Help Articles

You may have heard of "Blue Bolt Coating", its real name is Whitford Xylan® Coating... and it isn't always blue. Many of our customers ask for the "Blue Bolt Coating", but what exactly is Xylan and when should it be used?



Xylan is a blend of fluoropolymers, engineering plastics and selected corrosion inhibitors which, when combined, create these characteristics in fasteners:

• Low friction
  
  
• Exceptional adhesion
  
  
• Unusual resistance to wear and abrasion
  
  
• Excellent corrosion resistance
  
  
• Resistance to chipping
  
  
• Resistance to the weather, sunlight and salt water
  

Xylan's versatility is best demonstrated as a coating for stud Bolts and nuts, where it provides unparalleled performance in ease of installation, corrosion resistance and ease of removal. It can be used on standard alloy steel nuts and bolts, or can be paired with stainless steel fasteners for even more benefits.

Xylan fastener coatings or "Blue Bolt Coatings" are typically specified in oil and waterworks applications.



A bolt’s function essentially boils down to applying a high enough Hose Clamps force that when external forces are applied, transverse movement and separation cannot occur. Using calibrated torque tools to tighten fasteners and apply that clamp force is far superior to going by the user’s judgement or feeling. Or, as one senior technician calls it “The One Grunt or Two Grunts Method”. Measuring torque alone, however, does not ensure a proper installation.

1. Torque is an indirect indicator of Tension.

Torque is the measurement of twisting force needed to thread the fasteners together.

2. Tension is the force that actually holds an assembly together. Put another way:

A bolt can stretch similar to a spring, as it becomes tightened once all the parts of the assembly are brought together.

The higher the torque applied to the fastener, the more tension is created as the bolt stretches.



If a bolt is like a spring and more torque equals more tension, why does not a certain amount of torque always result in the same amount of tension?

Though the relationship between torque and tension is linear, many other factors can affect this relationship. Some of these factors include surface texture, rust, oil, debris, material type, locking elements and human error. Because of these variables, tightening to a specific torque setting can create varied results in the field or on the assembly line.



General commodity commercial fasteners do not fall under the umbrella of products that would require a UL listing or ICC-ES report. There are three main governing bodies that cover specifications for fasteners. ASTM (American Society for Testing and Materials) covers primarily bolts and fasteners for construction applications. SAE (Society of Automotive Engineers) covers fasteners for automotive, machinery, and OEM applications. ASME (American Society of Mechanical Engineers) standards B18.2.1 and B18.2.1 cover dimensional tolerances for square and hex head bolts, Screws, and Nuts. Mudge Fasteners provides fasteners to these three sets of specifications (ASTM, SAE, and ASME). A fourth specification group that is also applicable is AASHTO (American Association of State Highway & Transportation Officials). AASHTO specifications are typically only called out on highway projects and many AASHTO designations can be directly converted to an ASTM equivalent.

ICC (International Code Council) is the primary governing body responsible for writing and maintaining building, plumbing, mechanical, and fire codes adopted by local and state municipalities, and the federal government. ICC-ES (International Code Council-Evaluation Services, Inc.) is the branch of ICC responsible for performing technical evaluations of building products, components, methods, and materials to ensure that they meet the requirements of the codes. This evaluation process culminates in an ICC-ES report that provides evidence that the evaluated product or system meets code requirements. However, in the case of most anchor bolts and fasteners, the applicable sections of the codes (International Building Code, International Residential Code, International Property Maintenance Code, Etc.) direct you to the ASTM specifications covering said Anchors or fasteners. As the ASTM specifications already cover anchor bolts and fasteners in detail, there is no reason for ICC to write their own specifications for these items. For the same reason, ICC-ES does not need to perform evaluation testing of anchor bolts or fasteners. As long as the bolts meet the applicable ASTM specification(s), they will meet the applicable Code section(s).



When you are shortening bolt or Threaded Rods with a hacksaw, you always mangle the threads at the sawn end, making it difficult to get a nut threaded onto it. Reader Larry LeMasters tip produces a much better ending. Thread two nuts onto the bolt at the cutoff spot, tighten them against each other, then saw against the shoulder to create a clean right-angled cut. Next, loosen the nuts and file a slight bevel around the end to clear burrs created by sawing. Then spin off the nuts to clean and realign the threads. Your shorter bolt will work just like a new one from the box.



There are several distinct types of fastener, which may be referred to as a pin. These include small headless nails, sharpened pins used for holding fabrics while sewing, attaching paper to pinboards and the like, and several types of mechanical fasteners. Pins are an unthreaded mechanical fasteners, which are designed to be inserted through preformed holes.



Lock Washers and vibration-resistant washers are designed to prevent a threaded fastener from loosening. The terms are often used interchangeably. However, there is a difference.

Lock washers resist torque or loosening for a given preload, and vibration-resistant washers maintain a more constant preload when there’s movement in a joint. A lock washer may include some teeth to increase friction or tabs to provide positive locking. A vibration-resistant washer, on the other hand, will be sprung so that as the joint moves, a relatively consistent preload is maintained on the fastener.



Rivets are mechanical fasteners with a plain unthreaded shaft that are inserted through holes to join two or more parts together. A permanently formed head at each end prevents the rivet from removal from the hole. The shaft prevents any radial movements of the components. Depending on the type of rivet, and its ability to support shear load, it can resist considerable forces. The heads prevent axial movements of the parts, although less force is supported in this way.