Screw Plugs & Threaded Plugs with Standard M4–M12 or Fine Thread
Bülte's selection of screw plugs - also known as threaded plugs or sealing plugs - made from durable high-density polyethylene (HDPE) reliably seals tapped holes and thus protects components and pipes – without the drawbacks of metal alternatives. The robust plastic screw plugs are available with metric threads from M4 to M12, some also with fine threads. If necessary, they can be combined with washers made of silicone, neoprene or EPDM.
Our range includes threaded plugs with ergonomic knurled or wing heads for easy installation by hand, as well as with hexagonal heads (also know as hex plugs) and/or (cross) slots for fastening with standard tools. Thanks to their yellow colour, they can easily be identified, e.g. for cleaning or maintenance work. Other colours and dimensions are available on request.
High-Quality Plastic Sealing Plugs for Reliable Protection
Our sealing plugs combine the versatility of plastic with the strength required for demanding industrial applications. Whether for sealing threaded holes in mechanical assemblies or pipes, or for protecting threads from dirt, dust and other contaminants during storage and transport, our high-quality plastic screw plugs impress with their durability and long-lasting performance. They are particularly suitable for applications where chemical resistance, low weight and non-corrosive porperties are crucial.
Plastic Screw Plugs – Solutions for Industrial Applications
In addition to electrical insulation, the HDPE screws plugs also offer excellent resistance to moisture, oils, and many industrial chemicals —an ideal solution for use in mechanical engineering, hydraulics and pneumatics, the automotive industry and general industrial applications. Bülte screw plugs have been specially developed for industrial and commercial applications and are manufactured to strict quality requirements.
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FAQ Screw Plugs + Sealing Screws
What exactly are screw plugs used for?
Screw plugs are used to securely seal boreholes or threaded openings so that no liquids, gases or dirt can escape or penetrate. They can be reopened as required, e.g. for cleaning or inspection purposes. Screw plugs are therefore not used for fastening like normal screws, but primarily perform sealing, protective and maintenance functions.
Where are screw plugs used?
Screw plugs are used in engines and gearboxes as well as in hydraulic and pneumatic systems to securely seal oil channels, connections and service openings while allowing maintenance work such as oil changes or venting of systems. In mechanical and plant engineering, threaded plugs seal openings required for design or maintenance purposes and protect the interior of components from dirt, moisture and corrosion. In the automotive sector, screw plugs reliably seal test, filling and drain openings, for example, while still providing easy access for service and maintenance.
Are screw plugs also available with fine threads?
Yes, screw plugs are also available with fine threads. They are used wherever high tightness or precise positioning is required, or where space is limited. The smaller thread pitch allows for finer adjustment and generates higher axial forces with the same tightening torque. They are also better secured against loosening on their own. Typical applications for screw plugs with fine threads are:
- Hydraulic and pneumatic systems (e.g. test and measurement connections);
- Engine and transmission construction (e.g. oil, vent or control channels);
- Machine and plant construction, where short screw-in lengths or high sealing requirements exist.