Castair CNS34 — 3/4" Compression Nut and Sleeve
The CNS34 is a 3/4-inch compression nut and sleeve set from Castair, used in discharge tube connections on larger air compressor installations. The compression nut threads onto the fitting body; the sleeve (ferrule) compresses against the tubing OD as the nut is tightened, creating a sealed joint without soldering or flaring.
The CNS34 is the larger counterpart to the CNS12, matching the 3/4-inch discharge tube used on higher-output compressors. Use it to replace damaged or missing compression hardware on existing 3/4-inch discharge tube assemblies, or when building new connections using Castair DT34 discharge tubing or compatible 3/4-inch OD copper or appropriate tubing.
What This Part Does
- Compression Nut: Threads onto the male fitting body and drives the sleeve to compress against the tubing OD when tightened, forming a pressure-tight seal.
- Compression Sleeve (Ferrule): Deforms to conform to the tubing OD and fitting seat. Always use a new, undamaged ferrule — a previously compressed ferrule will not seal correctly when installed on new or different tubing.
- 3/4" Tube OD: Fits 3/4-inch outside diameter tubing. Compression fitting sizes refer to tubing OD — confirm your tubing is 3/4-inch OD before ordering.
- Replacement Part: Order CNS34 when original hardware is damaged, cross-threaded, or missing on an existing 3/4-inch discharge tube assembly.
Where This Part Is Used
- Discharge tube connections on larger piston air compressors using 3/4-inch OD discharge tubing.
- Pairs with the Castair DT34 (3/4-inch discharge tube with fittings) for complete discharge tube assemblies.
- Any compression fitting connection in the compressor discharge circuit using 3/4-inch OD tubing.
Related Castair Parts
- CNS12: 1/2" compression nut and sleeve — for smaller discharge tube connections
- DT34: 3/4" discharge tube with fittings — complete assembly that uses CNS34 hardware
- DT12: 1/2" discharge tube with fittings
- CA3434: Compression adaptor 3/4" x 3/4"
- CE3434: Compression elbow 3/4" x 3/4"
Technical Specifications
- Part Number: CNS34
- Tubing Size: 3/4" OD
- Contents: Compression nut and compression sleeve (ferrule)
- Application: Compressor discharge tube and compression fitting connections
- Manufacturer: Castair, Spicer, Minnesota
Why Buy From Air Compressor Factory Direct?
We have sold Castair parts and components since 2016. If you need to confirm the right compression hardware for your discharge tube size, call 866-217-0063 and we will sort it out. Free shipping on qualifying orders, full manufacturer warranty, free technical support.
Call 866-217-0063 for quick answers and help!
