Shoulder bolts are often referred to as shoulder screws or stripper bolts. They come in a variety of styles, lengths, and diameters including metric sizes. Shoulder screws are precision made and are manufactured in a number of materials. They are alphabetically designated A-F as identifiers to key size, weight, and thread size, and are extremely important to consider when making your shoulder bolt selection. Although names may vary with manufacturer, the basic types remain constant.
Shoulder Bolts In Action
The difference between shoulder bolt screws and other types of screws is that the shoulder bolt has a wide shaft that extends about 80% from the head to where the ridged, threading begins. Whereas, the threading ridges on normal screws extends the total length of the screw shaft. The most important feature about the design of the standard shoulder bolt is its blunt end. It is not tapered as regular screws making the shoulder bolt practical for many specialized uses. In fact, it is the shaft which provides the most important function of the design. Shoulder bolt heads also vary in shape and styles, such as hex and slotted that are fitted with a screwdriver or wrench. The round headed screw is fastened by screwing a nut on from the threaded end.
Using These Shoulder Bolts
Socket head shoulder bolts, or stripper screws are used in situations where clearance is low and limited, and when necessary to establish a pivot point or to hold something down without having to thread it. The use of a shoulder bolt allows applications such as wood, metal, and different parts of a machine to move, slide, and sometimes even rotate with relative ease. In other instances, they are used to align something, such as a spring in which threads would otherwise interfere. They can also be used to mount bearings to another surface.
Just a few examples of shoulder bolt uses are as follows:
- Sliding drawers use shoulder bolts as a type of axle
- Three-point tractor hitches use of the clevis pin for shear carrying
- Child’s wooden outdoor play sets use round head wood bolts which resist movement and lock into place
- Mower parts, such as deck wheels
- Rocker arms
The size of a head shoulder screw / stripper bolt is determined by length of the shoulder and the diameter. To determine the bolt thread’s length, multiply 2 by the head’s diameter and then add 1/2 inch. For instance, if the diameter of the head measures a quarter inch, multiply this by two to get 1/2 inch, and then add a half inch, arriving at a total length of one inch.
Use shoulder bolts made of stainless steel as they will hold up to any corrosion. This also makes it the best choice for any marine use. Alloy steel is best for situations requiring extreme hardness and strength and is better for interior purposes. Applications that require shear strength should use shoulder bolts that have undergone cold headed processing. Heat treated shoulder bolts have a black oxide finish. They come in a variety of styles, lengths, and diameters including metric sizes. Shoulder screws are precision made and are manufactured in a number of materials, although stainless steel seems to be especially favored. They are alphabetically designated A-F as identifiers to key size, weight, and thread size, and are extremely important to consider when making your shoulder bolt selection. Although names may vary with manufacturer, the basic types remain constant.
Most bolts, including the shoulder kind and elevator bolts, are graded according to how many pounds it would require to break them. For instance, on the high end, grade 8 shoulder bolts require 56,000 pounds to break a 3/4″ bolt. A grade 2, by contrast, requires less than 25,000 pounds. With great strength like that, it’s small wonder that shoulder bolts are so relied upon when extra durability is needed.
All About Elevator Bolts
Historically, elevator bolts were commonly used in attaching elevator buckets to belts in vertical conveying, has a wide variety of uses. It is most beneficially used in attaching to canvas and other soft, flexible materials. Common examples of use are in industrial and agricultural belting and conveying systems where there is not much space for large bolt heads and where one is in need of a wide, thin bearing surface. Although the elevator bolt is most often used in the agricultural industry, it has some more common, household uses such as leveling feet for appliances. This fastener is often used to hold down flooring in trailers, pontoon boats, mobile homes, and recreational vehicles.
Elevator Bolts Need To Be Sturdy
Because of the serious weight that these shoulder bolts must carry, it’s important that they be made of a strong material. Galvanized steel and stainless steel are sturdy and often used. There are also chrome plated elevator bolts. Grips are also important and should be sturdy enough to withstand the heaviest loads.
The Norway Elevator Bolt
- This bolt, named for its place of origin, is a round head bolt, unique because of its large flat countersunk head.
- The unusually large, smooth head decreases chances of the bolt pulling through the material being fastened together.
- The head of this bolt is also wrapped in abrasion, resistant material, which is important for uses where the bolt head needs to be protected from sliding material.
- This bolt’s head can also be pulled flush into a belt which will reduce the risk of rip out of bolt due to head protruding from back of belt.
- Crafted under its flat head is an integrally-formed square neck, which prevents turning when the nut is fastened to the bolt.
- Under its square neck is a standard UNC thread but can also now be found in metric threads and diameters.
- Elevator bolts are commonly made from low-carbon steel and are suitable for recessed or non recessed bolt holes.
Standard elevator bolt sizes are from ¼ to ½ in diameter, although other diameters can be found in limited quantities. The length of the threaded portion of the shaft on standard elevator bolts that are up to 6 inches in length is 2 times the diameter of the shaft plus 1/4 inch. For elevator bolts over 6 inches in length, the length of the threaded portion of the shaft on standard elevator bolts is 2 times the diameter of the shaft plus 1/2 inch.
There are two variations to the standard, Norway elevator bolt described above:
- One variation is the ribbed head elevator bolt. Instead of the square neck, located under the bolt head, this variation has a six-pointed radial star. Its flat head is smaller in diameter than the standard elevator bolt.
- The second variation is called a fanged elevator bolt, which has two sharp teeth under the bolt head. This variation is useful when the head of the bolt is difficult to hold during tightening. There is also the nail point bolt.
Elevator bolts, although not often manufactured in the United States, are readily available and distributed by many companies due to great amounts of importing. Well known elevator bolt types are Euro, Fang, Easifit, Ref70 and Easifit. Although originally designed for a specific purpose, the elevator bolt is now a widely used fastener very helpful in the household as well in industry and agriculture.