RA921 - Miller Smith RA921 12.5ft Grade R Oxy-Acetylene Hose (B-to-A Fittings)

Miller Smith RA921 Grade R Oxy-Acetylene Hose (12.5ft)

The Miller Smith RA921 is a premium-quality twin welding hose designed for specific oxy-acetylene setups that require different connection sizes at the regulator and the torch. Manufactured by Miller Electric under the renowned Smith brand, this hose is built to meet the rigorous demands of professional welding, brazing, and heating applications. It is a Grade R hose, meaning it is specifically engineered for use with Acetylene gas only and should not be used with alternate fuel gases like Propane or Propylene, which require Grade T hoses.

One of the defining features of the RA921 is its fitting configuration. It connects to standard industrial regulators via "B" size (9/16" - 18) fittings, which are the industry standard for most gas cylinders and regulators. However, the torch end is terminated with "A" size (3/8" - 24) fittings. This makes the RA921 an essential accessory for users operating light-duty torches or specific aircraft-style torches that utilize the smaller "A" inlet threads. This eliminates the need for bulky adapters at the torch handle, ensuring a lighter, more ergonomic grip during precision work.

With a length of 12.5 feet, this hose is ideal for fixed workstations, jewelry benches, or small fabrication shops where a standard 25-foot hose might create a tripping hazard or unnecessary clutter. The 3/16-inch inside diameter ensures sufficient gas flow for light-to-medium duty tips without adding the weight and stiffness of a larger 1/4-inch hose. The hose is color-coded—Green for Oxygen and Red for Acetylene—to ensure proper setup and safety compliance.

Key Features

• Specific Fittings: Connects B-size regulators to A-size torches directly.
• Grade R Rating: Safe and reliable for Acetylene gas service.
• Optimal Length: 12.5 feet provides reach without excess bulk.
• Lightweight: 3/16" ID reduces fatigue during fine manipulation.