Name: Threadolet
Brand: Cunimet Alloy International

Product Overview

Threadolet

The Threadolet is an integrally forged, self-reinforcing branch connection fitting that combines a welded-on branch outlet body with a female NPT threaded end, eliminating the need for a separate reinforcing pad while allowing a threaded branch connection to be made directly on the run pipe. The fitting base is welded to the run pipe over a drilled hole. The branch pipe or valve is then screwed directly into the female NPT thread at the top of the Threadolet.

The Threadolet is the preferred fitting for creating instrument tapping points, chemical injection connections, drain and vent branches and small-bore screwed connections on large-diameter piping headers, pressure vessels and columns. It avoids the need for a half coupling or separate branch fitting welded to the run pipe, providing a single-piece, integrally reinforced solution.

Cunimet Alloy International manufactures Threadolets in all standard run-to-branch combinations per MSS SP-97 in Class 3000# and 6000#. All NPT threads are CNC-cut to ASME B1.20.1 tolerances and 100% go/no-go gauge inspected. The base contour is machined to match the specified run pipe OD, ensuring full saddle contact before welding.

MSS SP-97 ASME B1.20.1 (NPT) ASTM A182 Run: 1/2"–24" NPS Branch: 1/8"–4" NPS 3000# • 6000#

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MSS Standard SP-97

NPT Thread Type Female, ASME B1.20.1

1/2–24" Run Pipe Range NPS

3000# Pressure Class Also 6000#

3 Material Grades SS / Duplex / S.Duplex

Technical Dimensions

Threadolet — MSS SP-97 Branch Dimensions

“H” = Overall height from the run pipe contact face to the top face of the NPT thread outlet. Thread form per ASME B1.20.1. BSP threads to BS EN 10226 available on request. All dimensions in millimetres.

Branch NPS	Pipe O.D. (mm)	Height “H” (mm)		Thread Form	Threads per Inch (TPI)	End Type
Branch NPS	Pipe O.D. (mm)	Class 3000#	Class 6000#	Thread Form	Threads per Inch (TPI)	End Type
1/8"	10.3	32	38	NPT	27	Female Threaded
1/4"	13.7	35	41	NPT	18	Female Threaded
3/8"	17.1	38	44	NPT	18	Female Threaded
1/2"	21.3	44	51	NPT	14	Female Threaded
3/4"	26.7	51	57	NPT	14	Female Threaded
1"	33.4	57	67	NPT	11.5	Female Threaded
1-1/4"	42.2	67	79	NPT	11.5	Female Threaded
1-1/2"	48.3	76	89	NPT	11.5	Female Threaded
2"	60.3	89	102	NPT	11.5	Female Threaded
2-1/2"	73.0	108	121	NPT	8	Female Threaded
3"	88.9	121	140	NPT	8	Female Threaded
4"	114.3	146	165	NPT	8	Female Threaded

Heights are nominal per MSS SP-97. Base contour radius machined to match specific run pipe OD. BSP threads per BS EN 10226 available on request. All standard run-to-branch combinations available. All dimensions in millimetres.

Available Materials

Material Grades for Threadolets

Grade 01

Stainless Steel 304 / 316

Austenitic stainless steel Threadolets for chemical plant instrument connections, drain and vent tapping points on process piping and utility headers. SS 316 is preferred for chloride-containing service, marine environments and offshore topsides.

ASTM A182 F304 ASTM A182 F316 MSS SP-97

Grade 02

Duplex Steel

High-strength duplex Threadolets for offshore process piping instrument points, chemical injection connections and branch tapping points on large-bore piping headers where chloride corrosion resistance and high yield strength are both required.

ASTM A182 F51 UNS S31803 UNS S32205

Grade 03

Super Duplex Steel

Premium super duplex Threadolets with PREN greater than 40 for instrument tapping and chemical injection connections on seawater service lines, desalination plant headers and aggressive offshore process piping systems.

ASTM A182 F53 UNS S32750 UNS S32760

Quality & Compliance

Standards, Testing & Documentation

Applicable Standards

Standard	Description
MSS SP-97	Integrally Reinforced Forged Branch Outlet Fittings — primary standard
ASTM A182	Material specification for forged alloy and stainless steel fittings
ASME B1.20.1	NPT Pipe Threads — thread form, tolerances and gauging requirements
BS EN 10226	BSP pipe threads — available on request
ASME B31.3	Process Piping — branch connection and weld requirements
EN 10204	3.1 MTC standard; 3.2 with TPI on request

Quality Tests Performed

Test	Method / Scope
Chemical Analysis	OES per ASTM A182 for each heat of material
Mechanical Testing	Tensile, yield, elongation and Charpy impact where specified
Hardness Testing	Brinell or Vickers per ASTM A182 requirements
Thread Gauging	100% NPT go/no-go gauge per ASME B1.20.1
PMI	100% XRF Positive Material Identification on request
Dimensional Inspection	100% per MSS SP-97 — height, OD, thread and base contour

Applications

Where Threadolets Are Used

01

Instrument Tapping Points

Creating threaded tapping connections for pressure gauges, transmitters, temperature elements, sample valves and flow instruments directly on large-bore process piping headers and vessels without welding a separate half coupling.

02

Chemical Injection Points

Installing chemical injection quill assemblies on process pipelines using Stainless Steel or Duplex Steel Threadolets where the threaded outlet accepts the quill assembly with a standard male NPT connection for easy removal and replacement.

03

Drain & Vent Points

Creating drain, vent and purge connections on large-bore pipeline headers, process vessel nozzles and equipment drain manifolds where a threaded branch outlet provides both the structural reinforcement and the threaded drain valve connection in one fitting.

04

Pipeline Sampling

Welding Threadolets onto crude oil, gas and chemical pipelines to create threaded sample probe connections for quality testing, emissions monitoring and condition assessment of the process fluid at each tapping point.

Branch Outlets Range

Threadolet — Threaded Branch Outlet