Posted by Jim Gillespie on | Comments Off on Three Critical Fastener Truths
“Your bolts are breaking in my engine blocks!”
The purchasing manager was furious!
This was a massive, costly failure. Someone would pay.
The unimpressed fastener engineer on the other end of the phone replied wryly. “What did you want to break?”
It was simple. Tremendous shear and tension had built, and something had to break. “Did you want it to be the bolt? Or the block?”
This made the auto executive stop.
The fastener engineer did not design the engine. He did not design the joint. His company supplied the bolts that held the engine together. And the bolts were up to the specifications they should have been made to. There was no disagreement as to any of these facts.
The problem here was not a bad bolt, it was a bad joint design, resulting in a tremendous strain on the joint. The joint design was creating shear on the bolt, far exceeding what the bolt was designed for.
Something had to give, and the preferred item to give was the bolt going into the block, not the block itself. Now this happened around the 1980’s, so the dollars might have changed, but the principle hasn’t: It’s much less expensive to replace a $15 bolt than it is to replace a $1,500 engine block.
Critical Fastener Truth #1: “Bolts are made to break.”
In the case of our Detroit friend here, the bolts were actually performing up to specifications. If a stronger bolt was used, it could have resulted in damage to the block itself, and that would render the block as scrap iron. The problem was the design of the joint itself, not the bolt.
Often, even experienced engineers tend to forget their fastening technology basics. It’s important that the proper fasteners are chosen, and as tension is brought to bear, It may require a period of relaxation and then a final tightening in order to reach and retain the proper tension.
Only when all the pieces of the puzzle are together can you be assured of holding the proper tension.
Critical Fastener Truth #2: Bolts Stretch.
What about disassembly and reassembly? Bolts are like rubber bands, they stretch and become deformed. They are subject to elasticity. Once put under load they cannot be returned to their pristine new shape. This often-overlooked principle can cause havoc on a high strength application, for example, a 60-ton capacity heavy duty construction crane turntable. And once one bolt fails, the entire turntable deck is compromised. Sadly, when a device of that critical strength fails, lives can easily be lost.
Critical Fastener Truth #3: Hydrogen Embrittlement.
One of the first things I ever learned in this business was learned the hard way. Well, the hard way, but it could have been far worse.
A customer had called desperately searching for stock on a high strength bolt. We happened to have stock, and we were ready to send it, when we saw some discoloration on the bolts.
Knowing the customer needed a cosmetically appealing solution, we quickly sent the parts out to our local plater to be flashed zinc before we sent them.
This worked wonderfully at the time, until the customer used their air guns to install the bolts, and watched the heads pop off.
Being new, I was not aware of the critical potential for hydrogen embrittlement to weaken the strength of the bolt and make it much more susceptible to break far below the required specifications. For some reason no one ever realized the need to heat treat these bolts to dissipate the hydrogen atoms throughout the bolt.
Thankfully, while this was a painful lesson, these bolts never made it through the rejection process, and no one was hurt.
In short, there are many factors that go into a good fastener joint. This includes proper fastener selection, a good understanding of what a joint is designed to do, and potential factors that can degrade a high strength fastener to the extent that they are unable to properly hold the load they were designed to hold.
When looking for fastener supply, look not only for the item, or for the cost-effective price. Look for a fastener supplier who is trained in fastener technology, who understand the fundamentals of fastener joint design, and is aware of the potential issues resulting from plating and secondary processes.
Fast-Rite engineers are available to discuss your fastener challenges. Just reach out to Fast-Rite Engineering at 888.327.8077 or email firstname.lastname@example.org.
Posted by Jim Gillespie on | Comments Off on How to reduce “Cam-Out”
Cam-Out – we’ve probably all experienced it.
Perhaps we’re putting a faceplate on an outlet, or driving into metal.
So we pull out our trusty slotted screwdriver, and start to turn the screw.
But the slot depth is shallow, perhaps it’s a struck slot instead of a saw slot, or maybe, this screwdriver has seen a lot of days and it’s worn, so the screwdriver slips out of the slot, perhaps across the application surface, and mars the surface.
BTDT: Been there, done that.. And hated it!
It is said the two most common complaints for screwdriver users are slipping or “Cam-Out”, and stripping/damaging a screw head). I’d rank Cam-Out as number 1.
Too much torque on the screwdriver, and the blade breaks out of the slot and slides wherever the torque pushes it. The more torque, the more likely it is to damage a work surface. This likewise can be true removing screws, and even more so if you’re using a power tool.
In 30 years in industry, I have often found myself despising the slotted screw.
But all things have a purpose, right? Until recently, I had never, ever thought that perhaps this slippage was by design. But it’s said the intent was to avoid damaging work through excess torque.
A BETTER SOLUTION
A better solution might be a six-lobe, ACR or Philips drive, which have much better BER – Bit Engagement Ratios. More importantly, not only do they engage better, they also tend to stay within the drive if it does Cam-Out. That means less damage potential.
Head types (round, pan, flat, etc.) certainly can play a factor also.
There are many types of drives available. Finding the right combination of Bit Engagement really isn’t rocket science.
A combo drive often performs much better. A Philips / Square / Slotted / Hex drive for example, will allow you to do most anything. But that does require s hefty head height.
Typically deck screws often have either Phil / Square flat heads or ACR II bits. Either one has superior bit engagement.
STEPS TO BETTER ASSEMBLY PERFORMANCE
Want better assembly performance?
-Review your tools.
-Set your torque properly.
-Make sure your bits are in good shape.
-Replace any worn tooling regularly.
Get help! Call a Fast-Rite pro at 888.327.8077 and explain your use case.
The right drive can make your life much easier, speeding assembly, maximizing torque, and minimizing cam-out, saving time, preventing damage and resulting in a better joint.
For help in finding a drive or bit selection, Call a pro at 888.327.8077, or email us at email@example.com.
Posted by Alice Maniev on | Comments Off on Platings and Coatings
What is the main purpose for plating and coating hardware?
Hardware is usually coated or plated for corrosion resistance. Corrosion can seriously affect the performance of hardware and so it may need these secondary processes to extend its lifetime. The main difference between the two is that coatings utilize a specific solution and do not change the chemical genetic makeup of the parts.
Types of Platings
The two main types of platings are electro and mechanical. The default, and more economical option of the two, is electroplating. This process occurs when a metal substrate is coated with a sacrificial layer by “electrolytic disposition”. The direct electric current creates a chemical reaction to provide a uniform covering of the metal when the hardware is placed in the electrolyte solution. Electroplating usually has a more appealing finish compared to mechanical plating methods.
Mechanical plating does not require extreme temperatures or electrical charges, instead it relies on a form of cold-welding force and chemical reaction to coat the surface of the part. This means parts do not need to be stripped prior to plating. High grade steel and alloy steel items are suitable candidates for this type of plating. The biggest advantage for mechanical plating is that it “does not produce hydrogen embrittlement and does not require a post-bake cycle.” Hydrogen embrittlement must be prevented because embrittlement can cause reduced ductility and a lessening of load-bearing capacity. This can lead to cracking and brittle failures, when subjected to loads below the anticipated proof or yield strength of the susceptible materials, i.e. strength is significantly decreased.
Types of Coatings
An advantage of coating as opposed to plating is that this process does not change the chemical composition of the parts. Types of coatings include acrylic, alkyd, epoxy, and zinc-rich. If you have taken an art class in the past, it is likely that you have come across acrylic paint. Acrylic coating can provide a glossy finish. This type of coating is also quick-drying and requires less ingredients which makes the process more convenient. Alkyd coatings are sometimes a good choice for parts that industrial OEMs need. These coatings can be custom formulated to withstand turbulent environments like underwater or underground. In order for this coating to be more effective, heat maybe used to “speed the chemical curing reaction”. This type of coating also takes a longer drying period than some of the other types. Epoxy coatings are usually a mixture of a curing agent with an epoxy polymer. This type of coating is applied in multiple parts where a primer is selected as the base layer and then the epoxy is applied over that based layer. After that, a polyurethane topcoat can be added for aesthetic appeals and enhanced durability. Advantages to epoxy coating include abrasion resistance and strong adhesion to many surfaces. These coatings can also withstand extremely high temperatures, up to hundreds of degrees Fahrenheit, which is higher than most coatings. Like the name suggests, zinc-rich coatings use zinc dusts as corrosion resistant materials to cover the parts. High performance organic zinc is mostly made with “epoxy or polyurethane resin binders”. Advantages of zinc coatings include a “galvanic (electrical current) and a polymeric barrier” and using it with steel can provide a dual layer corrosion protection for the part being coated. Fast-Rite offers the industry leading coatings from Magni, Doerken, and Geomet.
Posted by Alice Maniev on | Comments Off on Top Four Fastener Trends Observed in 2021
1. New Materials
“If it isn’t broken, don’t fix it…” But that isn’t Fast-Rite’s way. We say, “if it can be better, then why not?”. Fasteners were traditionally made from metal and plastic but there are other materials that can be more suitable with enhanced solidity. Materials such as ceramics, carbon fiber and special alloy can both be more durable and lighter in weight. We can even produce fasteners that can endure more extreme heat and pressure. For industries that require ultra-lightweight options, titanium fasteners may be the answer. For example, Titanium grade 5 has a strength-to-weight ratio of 29.1. Compared to a 9.2 of cold-rolled steel, there are some major differences there.
Ceramic (left), Inconel (top right), and carbon Fiber (bottom right)
We have all probably seen fasteners in watches, phones, computers, but they are also used in various medical devices, control panels, and in some lighting fixtures. The production of compactly designed devices drives the demand for tiny fasteners. There is potential there for an array of products and tools. For example, tiny screws need tiny screw insertions. There are automated or semi-automated small screw insertion tools available to make the installation process a lot less challenging.
Micro fasteners inside a watch (Photo by Felix Mittermeier from Pexels)
Carbon properties are susceptible to corrosion however, it is necessary for certain applications, depending on the durability and strength requirements. A variety of finishes or just a coat of paint can help combat corrosion. Stainless steel is also a good option for fasteners because it is corrosion resistant. At Fast-Rite, we offer corrosion resistant fasteners.
Is property and public safety important to you? Fasteners are everywhere and a lot of them are installed in visible and accessible places. It is staggeringly surprising how many individuals hijack various components and fasteners out of their intended applications. Security is essential which is why Fast-Rite puts in countless hours to ensure a wide range of high-quality fasteners and components exceeding industry standards. Some common examples are one-way screws and security pin drives. These would make removing fasteners in any application a more challenging task. In this case, that’s a good thing. Just think of the fixtures in a prison.
Prison fixtures (Photo by RODNAE Productions from Pexels)