What size of plug is in a 55 gallon drum?

plastic plugs

Standard drums can have different 55 gallon drum plug types. Usually, drums will have two different openings. (or bungs) One of them is always going to be a fine thread which in North America is 2″ NPS. (National Pipe Straight) In addition, the drum will always have a second bung which will either be large or small. If this secondary bung is large it is most likely a 63 mm buttress. technical details here. However it is often mistakenly called a 2-inch Buttress, but this is an inaccuracy. In any case, both of these threads are straight (not tapered like the NPT) and therefore they use an o-ring to provide a liquid-tight seal. If the second bung is small in diameter, it is almost certainly a 3/4 inch NPS thread in North America.

Buttress threads come in many different sizes around the world, and each container manufacturer seems to favor its own particular thread pitch and depth. Narrowing this to the chemical drum industry in North America, the 63 mm size is the most common. Occasionally this is also called a 2″ Buttress but this is an imprecise description. A nice feature of the Buttress plug is that it threads in place after only 3 turns or so. Also, the Buttress threads are much coarser than NPS and will never get stripped. Finally, because the threads are so coarse, it is easier to start the thread engagement than with a fine thread like the 2-inch NPS.

Drum Plugs Bungs

Plastic and metal drum plugs (bungs) and caps

Manufacturer and exporter of a complete range of drum plugs, cap-seals, and crimping tools compatible with drums (barrels) of all brands.

Custom Design: We also design and manufacture cap-seals, plugs, and tools for drums, cans, and any container as per customer requirements.

Worldwide door delivery.

Also available :

– Round-head steel drum plugs

– Drum plug gasket for metal and plastic plugs: Nitrile, EPDM, Silicone, and Viton

– Plastic and metal caps for bottles, cans, jars, and other containers

If you are interested in us, contact us now to get more detail!

Mobile/Whatsapp: 86-15033460318

Company email: mail@qiminggroup.com

FAQ

Q1: What are the standard thread sizes available for Qiming 55-gallon steel drum bungs?

A: We supply standard industrial 2-inch (G2 / 50mm) and 3/4-inch (G3/4 / 19mm) drum bung plugs with both coarse NPT threads and fine NPS threads. They are fully compatible with Tri-Sure, Rieke, and standard steel or polyethylene drum openings.

Q2: Are Qiming drum closures and bung plugs certified for hazardous chemical packaging?

A: Yes. Our steel drum bungs and cap seals are engineered to meet UN packaging standards and comply with international hazardous materials transport regulations (DOT/IMDG). Third-party pressure and tightness test reports are available upon request.

Q3: What surface finish options and gasket materials do you offer to prevent rust and leakage?

A: We provide trivalent chromium (Cr3+) zinc plating, Cr6+ galvanization, and stainless steel (304/316) options for high-corrosion environments. Gaskets are available in high-grade EPDM, Buna-N (Nitrile), PE, and PTFE (Teflon) to suit different chemical solvents.

Q4: Can we order custom logo printing on drum cap seals, and what is the sample policy?

A: Yes. We offer customized multi-color embossing and silk-screen printing on 2″ and 3/4″ tinplate or plastic cap seals. We support flexible MOQs for trial orders, and free standard product samples are available for customer quality testing.