What a Compression Nut Is
A compression nut is the female threaded fastener in the Bijur Delimon three-part compression fitting family. It threads onto a male compression bushing and drives the compression sleeve forward as it tightens. The nut itself does not seal the joint; it provides the clamping force that makes the sleeve bite into the tube and seat against the bushing.
Bijur and Delimon are trademarks of their respective owners.
This is an aftermarket part, not manufactured, sponsored, or endorsed by Bijur Delimon.
Bijur Delimon part numbers are for cross-reference identification only.
The assembly requires three matched parts: a male compression bushing threaded into the pump or manifold port, a compression sleeve placed over the tube, and the compression nut threaded onto the bushing. The nut must match both the tube outside diameter and the bushing thread. A nut alone cannot be specified without knowing the sleeve size and the bushing outlet.
Specifications
| Type | Compression nut, female threaded fastener |
| System family | Bijur Delimon three-part compression fittings, catalog B151 family |
| Tube sizes | 3/32, 5/32, 3/16, 1/4 inch and 4, 6, 8, 10 mm |
| Thread families | 1/4-28, 5/16-24, 3/8-24, 7/16-20, 7/16-24, M8 x 1, M10 x 1, M12 x 1.5, M14 x 1.5, M16 x 1.5 |
| Materials | Brass as standard, stainless steel as the corrosion-resistant option |
| Sealing principle | Internal taper drives the sleeve forward to bite the tube and seal against the bushing seat |
Cross-Reference Table
| Part number | Tube OD | Female thread |
| B3610 | 3/32 in (2.4 mm) | 1/4-28 |
| B3312 | 3/32 in | 5/16-24 |
| B1095 | 5/32 in (4 mm) | 5/16-24 |
| B3733 | 5/32 in | 5/16-24 |
| 34495 | 4 mm | M8 x 1 |
| 15327 | 4 mm | M8 x 1 |
| B1226 | 3/16 in (4.8 mm) | 3/8-24 |
| BB1226 | 3/16 in (4.8 mm) | 3/8-24 |
| B10089-1 | 1/4 in (6.4 mm) | 7/16-20 |
| B6087 | 1/4 in | 7/16-24 |
| AR194 | 6 mm | M10 x 1 |
| AR204 | 6 mm | M12 x 1.5 |
| AR205 | 8 mm | M14 x 1.5 |
| AR208 | 10 mm | M16 x 1.5 |
These numbers are supplier cross-references; confirm the exact number before ordering.
How the Nut Drives the Sleeve
The compression nut has an internal taper at its forward end. As the nut threads onto the male bushing, that taper contacts the rear of the compression sleeve. Continued tightening pushes the sleeve forward along the tube.
The sleeve is the sealing element. Its leading edge deforms against the bushing seat, and its inner bore bites into the tube outside diameter. The nut is the clamp that holds the sleeve in that deformed, seated position.
Because the sleeve deforms on first tightening, the nut can be removed and re-used on the same assembly during inspection. When re-making a joint on new tubing, replace the sleeve. The old sleeve will not reliably bite a fresh tube surface.
Inch and Metric Threads
This fitting family carries both inch and metric thread systems. A 5/32 inch tube assembly and a 4 mm tube assembly are close in outside diameter but not interchangeable. The bushing threads differ, and the sleeve bore is sized for a specific tube OD.
Mixing a 5/32 inch nut with a 4 mm sleeve or bushing will not produce a reliable joint. The thread may not engage, or the sleeve may not seat correctly. Always match the nut to both the tube outside diameter and the bushing thread.
When re-making a joint on new tubing, replace the sleeve even if the nut and bushing are re-used. The sleeve has already deformed to the old tube. A fresh sleeve is required for a correct bite on new tubing.
Related Parts
See compression sleeves for the ferrule that fits over the tube.
See compression bushings for the male threaded seat that receives the nut.
See centralized lubrication systems for the broader system context.
Request a quote through the quotation form.
Frequently Asked Questions
What does a compression nut do?
The nut threads onto the male bushing and drives the sleeve forward. The sleeve then bites the tube and seals against the bushing seat.
Can I reuse a compression nut?
Yes, you can reuse the nut on the same assembly during inspection. The sleeve is deformed on first tightening and should be replaced on new tubing.
How do I match a nut to my system?
The nut must match both the tube outside diameter and the bushing thread. You cannot match a nut without knowing the sleeve size.
What is the difference between B1095 and B3733?
Both are listed for 5/32 inch tube with 5/16-24 thread. Confirm the exact number before ordering because supplier data may vary.
Are B1226 and BB1226 the same part?
They are listed separately in the cross-reference table. Treat them as separate numbers until confirmed by a support engineer.
What materials are available?
Brass is the standard material for these compression nuts. Stainless steel is available as the corrosion-resistant option for demanding environments.
What is the working pressure rating?
Working pressure depends on tube size, wall thickness, and material. No single universal rating applies to all compression nut assemblies.
Can I use a 5/32 inch nut on 4 mm tube?
No, a 5/32 inch assembly and a 4 mm assembly are not interchangeable. The bushing threads and sleeve bores differ between inch and metric systems.
Why does the sleeve need replacement on new tubing?
The sleeve deforms permanently when first tightened onto the tube. A deformed sleeve will not reliably bite a fresh tube surface.
How do I order or get support?
IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006, builds and supports every unit. Email inquiry@isohitech.com for specifications and a quotation.
You can also request pricing through the quotation form. Include your tube size and bushing thread so a support engineer can confirm the match.
