Precision Stainless Steel Fasteners 101

Fasteners serve a relatively simple, but essential role: to mechanically join two or more objects together. In general, they are used to create non-permanent joints; that is, joints that can be removed or dismantled without damaging the joining components. They come in seemingly countless configurations, varying in shape, size and material.

For the markets we serve, one type stands out well above the rest: precision stainless steel fasteners. See, when it comes to mission critical applications in the aerospace, medical, electronics, food service and other demanding industries, reliable, predictable and precise fasteners must be used.

So, why is stainless steel the most popular material for these applications? Corrosion resistance. Further, they have a long life cycle, are environmentally friendly and are 100% recyclable. They are also resistant to high heat as well as extremely cold temperatures. Let’s look at a few different types of stainless steel fasteners and their applications.

Shoulder Screws

Shoulder screws are one of the more popular types of stainless steel fasteners. The shoulders give the screws their versatility by acting as shafts or dowels for rotating items such as bearings and bushings, axles for rolling parts, guides for sliding elements, and pivot points or mounting pins. Shoulder screws are often used in punch-and-die mechanisms or plastic-injection-mold sets.

Shoulder screws are usually available in 303 & hardened 416 stainless steel, with the choice of slotted, hex socket, or Philips head. Shoulder screws are available in metric & imperial sizes. You specify a shoulder bolt by its shoulder diameter and shoulder length. For example, a ⅜ × 2 shoulder bolt has a shoulder diameter of ⅜ in and a shoulder length of 2 inches.

Other types of stainless fasteners include dowel pins, set screws, thumb screws & nuts, retaining rings (internal & external), precision washers, & captive screws.

Learn more about our selection of shoulder screws. 

Dowel Pins

Dowel pins are used to keep machine components in accurate alignment; they are also used as location guides for adjacent machine parts and to keep the two sections of a punch and die in alignment. Our dowel pins are offered in metric & imperial sizes, in 303 stainless, and hardened 416 stainless per NASM 16555. Learn more about our selection of precision dowel pins. 

Set Screws

A set screw is a type of screw generally used to secure an object within or against another object. The most common examples are securing a pulley or gear to a shaft. Set screws are generally headless, meaning the screw is fully threaded and has no head sticking out past the diameter of the screw thread. Several types of set screws are available in metric and imperial sizes including:

• Standard cup-point stainless steel set screws - used for more permanent applications where shaft damage is not an issue.
• No-mar set screws - which have a nylon tip to prevent shaft damage.
• Silver-grip set screws - which have a silver tip soldered into the point and will withstand greater torque than the no-mar type, also without damaging the shaft.

Learn more about our set screw selection. 

Thumb Screws

Thumb screws and nuts are used in situations where the items being fastened together will need to be disassembled or adjusted frequently. This type of fastener can be loosened and tightened without the use of tools. They are offered in metric & imperial sizes. Learn more about our selection of thumb screws. 

Retaining Rings

External retaining rings are a semi-permanent type of fastener, used to locate bearings, collars, gears, pulleys, etc., on a shaft. Internal retaining rings are semi-permanent fasteners used to locate bearings, plugs, or other parts inside a housing or pillow block. These are available in metric & imperial sizes. Learn more about our retaining rings. 

Mechanical Fastener Alternative

The most discussed group of alternatives to mechanical fasteners are adhesives. While they can provide extremely strong bonds, this comes with a major potential drawback. Similar to a weld, adhesives provide a permanent bond. They are not removable, nor can they be disassembled, which is often a requirement for many mechanical applications. Depending on the specific use, adhesives can be a better choice.

If you need to reposition components, or disassemble them, then mechanical fasteners are the only way to go. If the application is critical, then a precision stainless steel fastener is your best option.