- 30. August 2023
- Posted by: Andreas Janisch
- Category: Sourcing
What are captive screws?
In the field of machinery and equipment manufacturing, captive screws play a pivotal role in numerous applications. These specialized screws are characterized by a unique design that prevents them from loosening or falling out after a component has been dismantled. The use of such screws is particularly essential in situations where the safety and integrity of machine components must be ensured by preventing any unintended loss of screws.
A practical example of the application of captive screws is in securing sheet metal panels to machines. In this case, a captive screw ensures that it remains connected to the panel even after the panel has been removed. This feature of the screws not only adds convenience but also, in many cases, meets legal requirements.
Captive screws are vital for compliance with machinery directives.
This aspect is not only convenient but often obligatory. The Machinery Directive 2006/42/EC mandates this property for safeguarding devices in order to enable CE marking: “The fasteners must remain connected to the safeguarding device or the machine after removal of the safeguarding device.”
The method of implementing this requirement is not prescribed. There are various constructive possibilities for this purpose. One option is the use of so-called E-washers, which are attached to the shaft of the screw after it has been inserted through the hole.
Another approach involves special screw-washer combinations, with washers that narrow their diameter after the initial tightening.
Why are captive screws relatively expensive?
Captive screws are offered by only a relatively small number of manufacturers and are produced in smaller quantities compared to conventional screws. This increases the costs of production and logistics. Additionally, the screw and washer must be precisely matched to ensure the clamping effect and thus comply with machinery directives. However, common systems are highly convenient to install and thereby save valuable work time.
An affordable alternative source for captive screws
For businesses in need of larger quantities of captive screws, an economical solution is to have them manufactured by contract manufacturers. We have extensive connections with such manufacturers and can provide you with a cost-effective alternative for sourcing these screws. If you are interested in larger quantities of captive screws for your operation, please feel free to get in touch with us via email.
Zuletzt überarbeitet am 16. November 2023 von Andreas Janisch