Nipples
A nipple is a short tubular fitting with male threads on both ends, used to connect equipment such as pumps, hoses and tools by threaded engagement. Besides same-thread nipples with identical threads at both ends, there are adapters that join different standards or sizes, such as G parallel threads to metric threads, or NPT taper threads to parallel threads. The listed products are mainly for high-pressure hydraulic use, with maximum working pressures in the range of 100 to 400 MPa. They are used to connect hydraulic tools and oil injectors (devices that use hydraulic pressure to press in or extract bearings). Parallel threads generally seal leaks with a sealing material or seating face, while taper threads generally seal through the wedging effect of the threaded portion.
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Nipples
Connecting Nipple (for Parallel Pipe Thread and Metric Thread)
A group of adapter nipples that connect hydraulic pumps and hoses to different thread sizes. Compatible with G parallel pipe threads and metric threads.
SKF
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Nipples
Connector Nipple (for NPT Taper Thread)
Nipple connecting NPT taper thread and parallel thread. Maximum operating pressure 100 to 150 MPa.
SKF
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Nipples
THPN M16x1,5 Thread Connection Nipple
Model: THPN M16G1/8 ほか
Nipple for connecting M16x1,5 thread and G thread. Maximum operating pressure 300～400 MPa.
SKF
How to choose Nipples
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1. Match thread standard and nominal size at both ends
Check the thread standard (G parallel, metric, NPT taper, etc.) and nominal size of both the connected equipment and the hose. Pitch must match exactly, such as M16x1,5. Parallel and taper threads are not interchangeable, so if conversion is needed, select the fitting by its end-to-end combination.
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2. Select a rating above the system's maximum pressure
The listed products have maximum working pressures from 100 to 400 MPa, and ratings vary by thread standard even for the same application. Determine the system's maximum pressure, including the pump's maximum discharge pressure and surge pressure, and select a nipple rated above it. The lowest rating among the fittings in the circuit sets the upper limit for the whole system.
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3. Confirm material suitable for pressure and fluid
High-strength steel is common for high-pressure hydraulic use. Check corrosion resistance to the working fluid and compatibility with the mating component material. Review the applicable fluid and surface treatment items to confirm there is no risk of galvanic corrosion from dissimilar metal contact or incompatibility with the fluid.
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4. Check overall length for routing and interference
The overall length of the nipple affects the distance between equipment and the routing of tools and hoses. Using the exposed length after subtracting thread engagement depth, check on the drawing for interference with surrounding parts and tightening tools. Note that an excessively long nipple is more susceptible to bending loads.
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5. Confirm wrench size and tightening torque
The listed products have wrench sizes of 22 to 32 mm. Confirm the tool size and workspace required for tightening in advance. Where a recommended tightening torque is specified (for example, 45 N·m), controlling it with a torque wrench helps prevent leaks from under-tightening and damage to threads or seating faces from over-tightening.
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6. Verify operating temperature and fluid compatibility
Confirm that the type of hydraulic oil and the fluid temperature fall within the product's operating temperature range and applicable fluids. If a sealing material is used together, judge its temperature resistance and oil resistance as well.
This guide was written by AI based on the listed products' documents and specification items. Check each manufacturer's documents before adopting.