Aftermarket Vogel/SKF Cylindrical Thread Connectors
This page describes aftermarket cylindrical thread connectors that cross-reference the Vogel/SKF lubrication system fitting range. Vogel and SKF are trademarks of their respective owner. These are aftermarket connectors, not manufactured, sponsored, or endorsed by SKF. Vogel/SKF part designations are for cross-reference identification only. These are straight male-to-male reducing adapters bridging a larger housing or port thread (d1) to a smaller tube connection thread (d2) in lubrication pipework. They are passive fittings with no check valve, no metering orifice, and no flow restriction. Each connector creates a tight threaded transition between the port and the tube.
How to Read the Part Number
Each part number encodes tube OD, d1 thread, d2 thread, body length, and material. All five parameters must be specified when ordering. For example, part number 301-005 is 6 mm tube OD, d1 M14 x 1.5, d2 M10 x 1, length 18 mm, galvanized steel.
Available Sizes
| Tube OD | d1 threads | d2 thread | Length range |
| 2.5 mm | M6, M8 x 1 | M6 x 0.75 | 13-15 mm |
| 4 mm | M12 x 1, M10 x 1, M14 x 1.5, M8 x 1 | M8 x 1 | 18-32 mm |
| 6 mm | M14 x 1.5, M10 x 1, M12 x 1, M8 x 1, G 1/8 | M10 x 1 | 18-23 mm |
| 8 mm | Similar range | Confirm by part number | Confirm by part number |
Materials
Galvanized steel is the standard material for these connectors. Stainless steel suits corrosive environments where rust or chemical attack is a concern. Brass can be selected for specific media compatibility. Material is a separate field in the part number, meaning the same base number can exist in multiple materials.
Where These Connectors Fit
These adapters sit between pumps, junction blocks, progressive distributors, and metering elements across SKF MonoFlex, MultiLine, and other Vogel/SKF system families. The d1 thread screws into the housing port. The d2 thread accepts the compression nut and ferrule for the tube. For related hardware, see progressive lubrication systems and what is a central lubrication system.
What to Confirm Before Ordering
Confirm tube OD from 2.5, 4, 6, or 8 mm. Confirm d1 port thread from the housing. Confirm d2 tube thread. Confirm body length. Confirm material. Confirm whether the compression nut and ferrule are included or ordered separately. If any thread is uncertain, contact the team with your housing and tube details.
Frequently Asked Questions
What do d1 and d2 mean?
d1 is the port or housing side thread. The d2 is the tube side thread that accepts the compression nut.
Do they contain a check valve?
No, these are passive threaded transition fittings only. There is no metering or check function.
What tube sizes do they support?
They support 2.5, 4, 6, and 8 mm OD tube. Each size uses a matching d2 thread.
What materials are available?
Galvanized steel is standard. Stainless steel and brass are also available.
What is part number 301-005?
It is 6 mm tube, M14 x 1.5 to M10 x 1. Length is 18 mm in steel.
Are nuts and ferrules included?
Not always, so confirm inclusion before ordering. Some part numbers include them.
Can I reuse the old nut?
Inspect the old nut for wear or thread damage. Replace it if deformed or cracked.
What pressure rating applies?
Confirm the connector rating against the circuit pressure. Do not rely on pump rating alone.
Will it fit my SKF pump?
Confirm the d1 thread from the housing port. Match it to the connector d1 thread.
Who builds these connectors, and how do I get a quotation?
IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006, builds and supports every unit. Email inquiry@isohitech.com for specifications and a quotation.
Contact the team with your d1 and d2 threads.
