What is a Machine Screw?
A machine screw is a type of fastener that, like, other fasteners, is used to join two or more objects. A machine screw is unique, though, because of its size. The American Society of Mechanical Engineers (ASME) defines machine screws as featuring a diameter of 0.75 inches. They can be smaller than 0.75 inches in diameter, but they can’t be larger than this size. As a result, machine screws are generally smaller than most other screws.
Because they are used in machines, A machine screw must be designed to withstand vibrations and liquids. If a machine screw is made of a weak material, it may crack when exposed to a machine’s vibrations. Machines often vibrate, and these vibrations can crack weak fasteners. Alternatively, low-quality machine screws may rust or corrode when exposed to moisture.
Machine Screws Types
A Machine screw is widely available in a variety of different sizes, head types, and drive types. materials.
Hex Head Machine Screws
Hex head screws allow for more torque to be applied to the screw with a socket wrench. Machine screws are most often used with a nut as a means of tightening unless they have a pre-threaded hole with the exact thread pitch. These screws are most commonly offered in smaller sizes.hex head machine screws may be installed using a standard wrench or spanner for extra torque. However, they may also have a recessed drive socket in the head, indicating that they are meant for use with a more typical screw driving tool.
Flat Head Machine Screws
Flat Head Screws, also called Countersunk Screws, is conical with a flat outer face and a tapering inner face. An advantage to this type of screw is that very little of the head protrudes beyond the surface, allowing it to sink into the material. These screws are commonly made out of stainless steel or zinc coating. Flathead machine screws are chosen for applications where the installed fastener needs to sit flush with the surface it is being driven into. A flattened top and countersunk underside profile mean that they offer a neat and flush surface finish on joined panels and components.
Oval Head Machine Screws
Oval head screws are a combination of a countersunk head and a domed head. Largely used as a decorative feature, the screw is countersunk but the top of the head still protrudes above the surface. Oval head machine screws offer something of a middle ground between the traditional, industrial pan head (round head) machine screw, and a flat head version. While pan head machine screws remain noticeably raised from the surface once driven home, oval heads are less noticeable due to a curved underside creating a slightly countersunk profile. However, they do not countersink as neatly as flat head machine screws
Cheese Head Machine Screws
A cheese head screw is one with a cylindrical head. “Cheese head” screws are defined by their head type. The cheese head has cylindrical sides with a flat disc top and a flat bearing surface. The head height is approximately half of its diameter and typically features a slot drive.
Drive types
- Slot: Slot screw drives have a single horizontal indentation (the slot) in the fastener head and is driven by a “common blade” or flat-bladed screwdriver.
- Phillips or Cross: cross drive machine screws have an X-shaped socket in the head, providing slightly more potential torque than a standard slot drive
- Hex: Hex bolts, or hex cap screws, are large bolts with a six-sided head (hexagonal!) used to fasten wood to wood, or metal to wood.
- Torx or hexalobular: A Torx screw is a six-lobed, star-drive socket or external head. A Torx screw is a type of screw characterized by a six-lobed, star-patterned screw drive. Torx drive is a trademark commonly referred to as star drive or, simply, a six-lobe. It’s often abbreviated to TX or 6lobe. The ISO name is hexalobular.
You can find machine screws available in many materials, including the following
- Titanium
- Stainless steel
- High-carbon steel
- Bronze
- Brass
- Aluminum alloy
- Nickel-copper alloy
Advantages of Machine Screws
Lots of people presume that Machine screws are utilized to connect steel things, such as equipment, with each other. While this makes good sense considering their name, the term “Machine screws” really describes reasonably little screws with a size of 0.75 inches or much less.
Machine screws are typically liked over various other, large screws. Due to their little dimension, they provide a larger series of applications. machine screws can be made use of to connect with plenty of kinds of items, objects as well as surface areas.
Machine screws are likewise offered in available various products. Stainless steel is a preferred product made use of in the building of Machine screws. It’s solid, sturdy, and also provides a high degree of security versus corrosion and also rust. Lightweight aluminum is an additional typical product utilized in the building of Machine screws. Like stainless steel, it uses security versus corrosion as well as deterioration. Lightweight aluminum machine screws aren’t as solid as their stainless-steel equivalents, yet they do not evaluate as a lot, either. For applications where weight is a worry, lightweight aluminum machine screws might be liked.
Machine Screws Sizes Dimensions
Cross Recessed Oval Pan Head Machine Screws
Screw Thread(d) | M2 | M2.2 | M2.3 | M2.5 | M2.6 | M3 | M3.5 | M4 | M4.5 | M5 | M6 | M8 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
P | Pitch | 0.4 | 0.45 | 0.4 | 0.45 | 0.45 | 0.5 | 0.6 | 0.7 | 0.75 | 0.8 | 1 | 1.25 |
dk | max=nominal size | 3.5 | 4 | 4 | 4.5 | 4.5 | 5.5 | 6 | 7 | 8 | 9 | 10.5 | 14 |
min | 3.1 | 3.6 | 3.6 | 4.1 | 4.1 | 5 | 5.5 | 6.5 | 7.4 | 8.4 | 9.8 | 13.2 | |
k | Nominal Size | 1.3 | 1.5 | 1.5 | 1.7 | 1.7 | 2 | 2.3 | 2.6 | 2.9 | 3.3 | 3.9 | 5.2 |
max | 1.4 | 1.6 | 1.6 | 1.8 | 1.8 | 2.15 | 2.45 | 2.75 | 3.05 | 3.45 | 4.1 | 5.4 | |
min | 1.2 | 1.4 | 1.4 | 1.6 | 1.6 | 1.85 | 2.15 | 2.45 | 2.75 | 3.15 | 3.7 | 5 | |
Socket No. | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 2 | 2 | 2 | 3 | 3 | |
m | max | 2.2 | 2.4 | 2.4 | 2.6 | 2.6 | 3.5 | 3.8 | 4.1 | 4.5 | 4.8 | 6.2 | 7.7 |
Penetration depth | max | 1.01 | 1.21 | 1.21 | 1.42 | 1.42 | 1.43 | 1.73 | 2.03 | 2.43 | 2.73 | 2.86 | 4.36 |
min | 0.6 | 0.8 | 0.8 | 1 | 1 | 0.86 | 1.15 | 1.45 | 1.84 | 2.14 | 2.26 | 3.73 |
Slotted Cheese Head Screws Dimensions Sizes
Screw Thread(d) | M1 | M1 | M1.2 | M1.2 | M1.4 | M1.4 | M1.4 | M1.4 | M1.6 | M1.6 | M1.7 | M1.7 | M2 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
P | Pitch | 0.25 | 0.25 | 0.25 | 0.25 | 0.3 | 0.3 | 0.3 | 0.3 | 0.35 | 0.35 | 0.35 | 0.35 | 0.4 |
dk | max | 1.5 | 1.8 | 1.8 | 2 | 1.8 | 2 | 2.5 | 2.8 | 2.5 | 2.8 | 2.5 | 2.8 | 3 |
min | 1.36 | 1.66 | 1.66 | 1.86 | 1.66 | 1.86 | 2.36 | 2.66 | 2.36 | 2.66 | 2.36 | 2.66 | 2.86 | |
k | max | 0.67 | 0.67 | 0.67 | 0.67 | 0.67 | 0.67 | 0.67 | 0.67 | 0.67 | 0.67 | 0.67 | 0.67 | 0.67 |
min | 0.53 | 0.53 | 0.53 | 0.53 | 0.53 | 0.53 | 0.53 | 0.53 | 0.53 | 0.53 | 0.53 | 0.53 | 0.53 | |
n | max | 0.4 | 0.4 | 0.4 | 0.48 | 0.4 | 0.48 | 0.48 | 0.48 | 0.48 | 0.48 | 0.48 | 0.48 | 0.48 |
min | 0.32 | 0.32 | 0.32 | 0.4 | 0.32 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | |
t | Nominal Size | 0.35 | 0.35 | 0.35 | 0.45 | 0.35 | 0.45 | 0.55 | 0.55 | 0.55 | 0.55 | 0.55 | 0.55 | 0.55 |
max | 0.4 | 0.4 | 0.4 | 0.5 | 0.4 | 0.5 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | |
min | 0.3 | 0.3 | 0.3 | 0.4 | 0.3 | 0.4 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 |
A widespread standard for sizing and
measuring screws according to diameter is by using the metric scale. For machine screws sold under metric gauges, the letter M will be followed by a number. The higher the number, the larger the screw will be in diameter.
Machine Screws vs Bolts: What’s the Difference
Machine screws may look like bolts, but they aren’t necessarily the same, However, machine screws are typically smaller than bolts, although a more precise distinction is the way that they are tightened in a tapped hole.
bolts typically require the use of a hex socket to install. They don’t feature a slotted head. Instead, bolts have a hex head that only works with a hex socket. To install a bolt, you must place a hex socket over the bolt’s head and then turn it. With machine screws, the majority of tightening force (torque) is applied to the head of the screw itself when driving it into a tapped hole.
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