These 3½" NC38 lifting caps (also called nubbins) feature an open-center design for safe and efficient handling of drill pipe, tubing, and tool joints in oilfield operations. The NC38 thread (Nominal Connection 38) is an API-standard thread commonly used in drill stem components.
✔ Thread Compatibility:
Common sizes: 2-3/8" to 20" (API or premium threads)
Example: 3-1/2" REG Box, 4-1/2" FH Box, etc.
✔ Load Capacity: 10–200+ tons (varies by size/material)
✔ Material: Forged alloy steel (AISI 4140/4142) with heat treatment
✔ Safety Locking: Some models include retainer pins to prevent accidental release
✔ Surface Finish: Machined smooth to prevent thread galling
Casing/Tubing Running – Protects threads during hoisting
Drill Pipe Handling – Safe lifting during rig operations
Workover & Well Servicing – Pipe tripping and laydown
Pipe Yard Logistics – Loading/unloading pipe shipments
| Parameter | Specification |
|---|---|
| Connection Type | Box (Female) – API or Premium Threads |
| Load Rating | 10–200+ tons (with safety factor) |
| Material Grade | AISI 4140/4142 (QT heat-treated) |
| Surface Coating | Phosphate, black oxide, or bare |
| Weight | 5–50 lbs (varies by size) |
Standard Box Lifting Cap – Basic design for general use
Open-Center Box Cap – Allows fluid drainage/inspection
Shouldered Box Cap – Reinforced for heavy-wall pipe
Quick-Release Cap – With locking pins for rapid deployment