Midland Industries 66767 Hex Socket Countersunk Plug 1-1/4 Mnpt

Product Description

The MIDLAND INDUSTRIES 66767 is a hex socket countersunk plug designed to seal threaded pipe openings in galvanized steel piping systems. It connects via a 1-1/4 inch MNPT thread with a 1-1/4-11-1/2 thread pitch and is rated for 150 lb pressure service. The zinc-plated steel construction provides corrosion resistance in typical indoor plumbing, gas distribution, and light industrial piping environments. At 0.385 pounds and 0.8 inches in length, it is a compact, durable pipe-end closure. The 3/4 inch internal hex socket accepts a standard hex key or Allen wrench for installation without external wrench flats, making it suitable for recessed or tight-clearance locations.

This plug is used in residential and light commercial piping systems where threaded steel pipe must be capped or blanked off at an open port. Common applications include natural gas and propane distribution piping, hydronic heating systems, compressed air lines, and general plumbing rough-in work. The countersunk hex socket design is well suited for installations where a flush or low-profile fitting is required. Plumbers, pipefitters, and HVAC technicians install this fitting as part of new construction, system modification, or cap-off service work.

Key Features

• 1-1/4 inch MNPT connection with 1-1/4-11-1/2 thread form for secure, leak-resistant fit
• 150 lb pressure class rating suitable for standard steel pipe service
• Zinc-plated steel construction resists corrosion in typical piping environments
• 3/4 inch hex socket drive allows installation with a hex key in tight spaces
• Countersunk profile provides a low-clearance, flush-style closure
• Meets ASME B16.14 - 1991 dimensional standards

Compatibility

Designed as an OEM-style replacement or standard-service fitting for 1-1/4 inch MNPT threaded steel pipe systems rated at 150 lb pressure class per ASME B16.14 - 1991.

Installation Notes

Installation is performed by licensed plumbers or pipefitters following applicable code requirements such as the IPC or IFGC depending on service type. Depressurize and isolate the piping system completely before installing or removing any threaded plug. Apply an appropriate thread sealant or PTFE tape to the MNPT threads before installation. Use a calibrated torque approach suitable for steel fittings and avoid over-tightening, which can crack fittings or damage threads.