TES-LOK Female Adapter Tube Fittings — double-ferrule compression tube one end, female internal NPT / BSP / SAE socket other end. Connects instrument tubing to male-studded valves, transmitters, manifolds, and process equipment. SS 316 · Brass · Monel · Inconel · Equal & Reducing · Up to 6,000 PSI · ISO 9001:2015 certified.
Female Adapter — NPT / BSP Series
Female Adapter — Range Overview
A female adapter tube fitting (also called a female connector or tube-to-female-thread fitting) has two distinct ends: a double-ferrule compression tube end that grips the tube OD via PTFE front and back ferrules, and a female internal socket end that threads over a male stud, nipple, or external thread on equipment or pipe fittings.
Female adapters are used wherever a tubing run must terminate at a male-studded device — a valve body with an NPT stud, an instrument with a BSP male nipple, or a manifold with an SAE straight-thread port. The female socket threads directly over the male stud, eliminating intermediate couplings.
| Variant | Thread Type | Seal Mechanism | Sealant on Male Stud | Typical Application |
|---|---|---|---|---|
| Standard Female Adapter (NPT) | NPT tapered (ASME B1.20.1) | Thread flanks taper-wedge | PTFE tape on male stud | Valves, gauges, pipe manifolds |
| Standard Female Adapter (BSPT) | BSPT R/Rc tapered (ISO 7-1) | Thread flanks taper-wedge | PTFE tape on male stud | UK / European process instruments |
| Female Adapter (BSPP / G) | BSPP G parallel (ISO 228-1) | Bonded seal on male stud face | Dowty washer on male stud | Hydraulic valves, European instruments |
| SAE / MS Straight-Thread Female Adapter | UNF straight (SAE J1926 / MS16142) | O-ring on male stud shank | None — O-ring on male stud seals | Hydraulic systems, analytical instruments |
| Reducing Female Adapter | NPT / BSP / SAE — different size to tube OD | As per thread type above | As per thread type | Large-bore tube to small male stud equipment |
With a female adapter, sealant is applied to the male stud that threads into the female socket — not inside the socket itself.
| Thread Standard | Thread Profile | Seal Location | Apply to Male Stud | Do NOT Use |
|---|---|---|---|---|
| NPT (ASME B1.20.1) | Tapered 60° | Thread flanks | PTFE tape (2 wraps) or anaerobic sealant | — |
| BSPT (ISO 7-1) | Tapered 55° | Thread flanks | PTFE tape or sealant paste | — |
| BSPP / G (ISO 228-1) | Parallel 55° | Bonded seal face | Dowty washer on male stud face | PTFE tape inside the female socket |
| SAE / MS UNF (SAE J1926) | Straight 60° | O-ring on male stud shank | Replace O-ring on male stud; no tape needed | PTFE tape — prevents O-ring seating |
| TES-LOK Female Adapter Tube Fitting — Specifications | |
|---|---|
| Brand | TES-LOK (by Tesco Steel & Engineering) |
| Tube end | Double-ferrule compression (TES-LOK bite-type) — PTFE ferrules (ASTM D1710/D3294) |
| Thread end | Female internal socket — NPT · BSPT · BSPP · SAE J1926 / MS16142 · UNF |
| Tube OD range | 1/8" – 1" (imperial) · 3 mm – 25 mm (metric) |
| Thread range | 1/8" NPT – 1" NPT and equivalent BSP / SAE |
| Configurations | Equal · Reducing |
| Body materials | SS 316 / 316L (standard) · SS 304 · Brass · Monel 400 · Inconel 625 · Hastelloy C-276 · Carbon Steel |
| Max. working pressure | 6,000 PSI (SS 316) · 3,000 PSI (Brass) |
| Temperature range | −196°C to +400°C (SS) · −29°C to +232°C (PTFE ferrule limit) |
| Standards | ASTM D1710 · ASTM D3294 · SAE J1926 · MS16142 |
| Certifications | ISO 9001:2015 · EN 10204 3.1 MTC available |
| Compatible systems | TES-LOK · Swagelok · Parker A-LOK · Ham-Let |
| Fitting | Tube End | Thread End | Equipment Port Type | Choose When |
|---|---|---|---|---|
| Female Adapter | Compression tube | Female internal socket | Male stud / external nipple | Equipment has protruding male thread |
| Male Adapter | Compression tube | Male external thread | Female port / internal socket | Equipment has recessed female port |
| Female Bulkhead Connector | Compression tube (inside panel) | Female socket (outside panel) | Male stud (outside panel) | Tube feedthrough panel + male-studded external equipment |
| Female Run Tee | Compression tube × 2 (run) | Female socket (branch) | Male stud (branch) | Branch from tube run to male-studded instrument |
Female socket threads directly over the male stud on the equipment — no intermediate union or nipple required. Compact, low-profile installation with a single fitting handling both the tube connection and the thread transition.
Inert to virtually all process fluids. No galling, no cold welding to the tube OD. Re-makeable without tube replacement — critical for systems with frequent instrument swaps.
NPT, BSPT, BSPP, and SAE/MS all available from one supplier. Covers North American, European, and hydraulic system standards without multi-vendor sourcing.
Reducing female adapters change tube OD and thread size simultaneously — no separate reducer bushing for mixed-size systems.
Manufactured under an ISO 9001:2015 quality management system. EN 10204 3.1 material test certificates and PMI testing available on request for all CRA grades.
Compression ends dimensionally match Swagelok and Parker A-LOK — direct replacement for maintenance and system expansion without re-tubing.
▶ What is a female adapter tube fitting?
A female adapter tube fitting has a compression tube connection on one end and a female internal thread socket (NPT, BSP, or SAE) on the other. It connects instrument tubing to male-threaded studs, nipples, or ports on valves, instruments, and process equipment.
▶ When should I use a female adapter instead of a male adapter?
Use a female adapter when the equipment connection is a male stud or external nipple. Use a male adapter when the equipment connection is a female port (internal thread). The female adapter socket threads over the male stud on the equipment.
▶ What thread sealant is used on female adapter tube fittings?
For NPT and BSPT (tapered), apply PTFE tape to the male stud that screws in. For BSPP parallel, use a bonded seal (Dowty washer) on the male stud face. For SAE/MS, the O-ring on the male stud provides the seal — no sealant needed.
▶ What is the pressure rating?
TES-LOK female adapter tube fittings in 316 SS are rated to 6,000 PSI at room temperature for standard tube sizes. Pressure ratings derate with increasing temperature and larger tube diameters.
▶ What materials are available?
316/316L stainless steel, 304 SS, duplex 2205/2507, monel 400, inconel 625, hastelloy C-276, and carbon steel.
▶ What tube sizes are available?
TES-LOK female adapters are available in tube OD from 1/8" to 1" (imperial) and 3 mm to 25 mm (metric), with female thread sizes from 1/8 NPT to 1 NPT and equivalent BSP sizes.
▶ What is a reducing female adapter?
A reducing female adapter connects a tube of one OD to a female thread of a different pipe size — for example, 1/2" OD tube to a 1/4" NPT female port. One fitting handles both the size change and the tube-to-thread transition.
▶ Are TES-LOK female adapters compatible with Swagelok and Parker?
TES-LOK female adapter compression ends are dimensionally compatible with Swagelok and Parker A-LOK fittings of the same tube OD. Verify compatibility before mixing brands in critical service.
NPT · BSPT · BSPP · SAE/MS straight-thread · Reducing — all in 316 SS, duplex, monel, inconel, and more. ISO 9001:2015 certified. Mill test reports supplied as standard.
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