What are these screws called?

Post 23

Gulmite screws are used on the sides of old Crown School Buses.

There are 24 points on the side of the head.

Post 20

What type of screw thread has an equilateral triangle thread form?

Post 19

Set screws are also used with nuts.

Post 18

A visual representation of the article.

@wanderer, the difference between bolts and screws are that both are externally threaded fasteners, but a bolt is intended to be tightened or released by a nut, while a screw is intended to be inserted into holes in assembled parts being tightened by torquing the head. Then you have bolts which are...

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What do the terms "G" and "C" mean in reference to ACME screw threads? What materials are your screw products made from? Are the screws difficult to machine? Can you provide end-machining services? What are the differences among ACME, HI - LEAD(tm) and TORQSPLINE(tm) product lines? Is there a standard for multiple start ACME screws as there is for single start ACMES? What is screw/nut galling and how can it be avoided? Your catalog doesn't show the size ACME screw I need, can you make it as a special? What is the customary way to call out screws? Are there benefits to using alloy ACME screws like Alloy 4140 Heat Treated steel in place of the low and medium carbon steel screws offered as standard? What does the term "B7" refer to? Do you offer plating on your screws? Would an extra long nut be...
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Can You Use Drywall Screws For Building Purposes?

Are drywall screws the new duct tape? Can they be used for purposes other than hanging drywall? There are two ways to look at this issue:

Why You Should Not Use Them

Conventional wisdom says that you should not use drywall screws for building. Drywall screws are designed for hanging drywall.

There are many arguments against using drywall screws for building projects:

Drywall screws tend to be brittle; rather than bending, they can snap. Heads are especially prone to cleanly breaking off, leaving the shaft section embedded in your wood. No screw extractor can remove a headless screw. They do not work for outdoor building.

No woodworker would ever use drywall screws for fine building. Avoidance of drywall screws is especially important with heavy or even moderate building tasks, especially outdoor projects like the pictured fence-building job.

Why They Are Fine To...

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System Manufacturer/Model Number custom build
OS windows 7 32BIT SP1
CPU intel pentuim d 3.00ghz @ 3.50ghz
Motherboard gigabyte p43
Memory 8gb ddr2 800mhz
Graphics Card ati hd pro 1gb
Monitor(s) Displays 42" lg full hd led tv
Screen Resolution 1920x1080p

PSU 750w
Case custom build with windows in orange and black
Cooling air cooled
Hard Drives 300gd 10000rpm WD main drive and 3x 2tb storage drives
Internet Speed 8mb down and 1.1 up

System Manufacturer/Model Number Built be Me
OS Windows 7 Pro x64
CPU i5 760
Motherboard Asus P7P55D-E Pro
Memory 16GB
Graphics Card Nvidia GTS450
Sound Card On board
Monitor(s) Displays Dell 2007WFP Dell 1800FP
Screen Resolution 1680x1050 1280x1024

Keyboard IBM
Mouse MS
PSU Antec 750
Case In Win
Cooling Cooler Master Hyper 212+
Hard Drives...

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a cylinder, or a cylindrical perforation, having a continuous rib, called the thread, winding round it spirally at a constant inclination, so as to leave a continuous spiral groove between one turn and the next, -- used chiefly for producing, when revolved, motion or pressure in the direction of its axis, by the sliding of the threads of the cylinder in the grooves between the threads of the perforation adapted to it, the former being distinguished as the external, or male screw, or, more usually the screw; the latter as the internal, or female screw, or, more usually, the nut


specifically, a kind of nail with a spiral thread and a head with a nick to receive the end of the screw-driver. Screws are much used to hold together pieces of wood or to fasten something; -- called also wood screws, and screw nails. See also Screw bolt, below


anything shaped or acting like a screw; esp., a form of wheel for...

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What is Backlash?

Take a large machine screw and thread a nut onto it. Now hold the head of the screw between the fingers of one hand and hold the nut between the finger of the other. If you push and pull on it as if you are trying to push the nut onto the bolt and then pull it off you’ll be able to feel a small amount of movement between the screw and the nut. This movement is the result of the fact that the threads of the nut do not fit snugly around the threads of the screw – there is some space in there. Figure 1 shows a hunk of threaded rod and a cutaway of a nut around it. You can see the space between the threads of rod and the threads of the nut. This space is called backlash.

Backlash is a measurable quantity. The simplest way to measure it in a screw and nut is to push the nut as far as it will go in one direction and then to measure how far it can move in the other direction. Figure 2 shows the same cutaway diagram of the screw and nut with the nut...

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by Chris Woodford. Last updated: June 3, 2016.

It's built to last you a lifetime—quite literally. But though the human body is the most amazing tool at your disposal, it often needs a helping hand. Tools made from metal, wood, and plastic work like extensions of your body, making you feel stronger and helping you work faster and more efficiently. In science, tools like this are called simple machines. And although you might think there's a big difference between a tiny little wrench and a huge great earthmover, exactly the same physics is at work in both. Let's take a closer look at tools and machines and how they work!

Photo: This hydraulic digger uses a collection of simple machines (wheels, axles, and levers) to magnify the force its driver can exert.

What is a machine?

To do anything at all—to lift a box, to push a car, to get out of bed, to jump in the air, to brush your teeth—you need to use a pushing or pulling action called a force. If...

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"Barrel bolt" redirects here. For the type of latch called a barrel bolt, see

Latch (hardware)


A sex bolt, (also known as a barrel nut,[1]barrel bolt, 'Chicago screw' or post and screw),[2][3] is a type of fastener (nut) which has a barrel-shaped flange and protruding boss that is internally threaded. The boss sits within the components being fastened, the flange provides the bearing surface. The sex bolt and accompanying machine screw sit flush on either side of the surfaces being fastened. It is normally chosen because of its low profile compared to other nuts. The sex bolt often has a built-in feature, such as a slot, to aid in tightening the fastener. Some sex bolts, more commonly known as 'architectural bolts', have knurled barrels to allow one-sided assembly. 'Binding posts' are similar to architectural bolts in that they are designed to be assembled from one side, but they have teeth on the flanged surface to keep them fixed.

A sex bolt is a mating...

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A ball screw is a device that converts rotational motion into linear motion by using a ball screw nut that runs up and down a screw on ball bearings that travel in helical grooves. Also sometimes called linear ball screws, these devices are used to create the movement necessary to move parts and devices along a single axis. Ball screws translate torque into thrust through ball screw assemblies that consist of a screw and a nut. The threading of the screw and the threading of the nut match one another. Ball bearings roll in the grooves of the threads to provide a rolling friction and smooth motion. A deflector inside the nut’s ball return system redirects the balls to the opposite end of the ball screw nut so that the balls are continuously recirculating. Ball screws are beneficial for a variety of reasons. Ball screws offer high levels of efficiency that measure approximately 90% while maintaining low energy consumption levels. Ball screws are available in a number of variations....

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Screws are designed for a variety of purposes, though most are primarily intended to fasten two surfaces together. Screws can be used alongside Washers to prevent damage to the target housing, and with Square Nuts or Hexagon Nuts to lock the fastener in place from behind. All screws are characterised by an external thread along the shaft, and most feature some type of head.

Machine Screws

Machine Screws (sometimes called machine bolts) are generally manufactured in smaller thread sizes than standard Screws, and are often fully threaded. Machine Screws are often driven into tapped holes, or are used alongside Nuts to fasten tightly – though Self-Tapping and Thread-Locking variants are available.

The AccuScrews Range

AccuGroup's Precision Screws are manufactured to extremely tight tolerances, and are designed to provide accuracy and precision in a range of high-performance applications. Our fasteners are available in A2 and A4 Stainless Steel, as well...

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The Type A and AB self-tapping screws are your normal sheet metal screw with a fairly sharp point. Self-tapping is the ability of a screw to advance when turned while creating its own thread. They are commonly used with sheet metal and plastic components. This ability is created sometimes by creating a gap in the continuity of the thread on the screw. These edges can cut their own threads as the screw is driven in to the material, usually wood or plastic, as well as for metal. They function by having a cutting edge which drills away the material, making a hole for the screw to go into. They come in hex head (slotted or unslotted), hex washer, slotted and Phillips flat head, pan head, oval head, truss head and round head. We also have pan square recess and flat square recess head. Torx pan head Type AB are also available. You can also find stainless steel and hardened steel, black oxide plated.

Type B...

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Using the right kind of screw is essential to any construction project, large or small, whether you are a contractor doing a renovation or a builder erecting an entire residential subdivision or office complex. You need screws specifically manufactured for the material to be fastened — whether it’s concrete, wood, metal or something else — and that will hold up for their designated use. At Fastener SuperStore, Inc., we provide a wide range of options for customers looking to buy wholesale screws of virtually any type. Below is a list of screw categories and some common uses, along with information about what Fastener SuperStore, Inc., can do for you.

Screws and Their Uses

Fastener SuperStore, Inc., is your best bet when you have to buy bulk screws for practically any application. Here are some of the most common uses for various types of screws that we carry:

Concrete screws are incredibly tough and made specifically for firm placement in concrete and...
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