MC40-4 - Miller Smith MC40-4 Propane Cutting Tip, Size 4, 2-Piece

Technical Overview of the Miller Smith MC40-4

The Miller Smith MC40-4 is a specialized cutting tip engineered for oxy-propane and natural gas cutting applications. As part of the MC40 series, this tip features a two-piece construction, a design necessity for alternate fuels like propane which have a lower burning velocity than acetylene. The two-piece assembly consists of an inner member with splines for gas flow and an outer shell that creates a recess at the tip end. This recess acts as a flame holder, preventing the flame from blowing off the tip even at high pressures, ensuring a stable and consistent preheat flame.

This specific model is a Size 4 tip, characterized by a #68 drill size for the cutting oxygen orifice. This bore diameter is calibrated to deliver a high-velocity oxygen stream capable of severing carbon steel plates up to 4 inches (102mm) in thickness. The medium preheat configuration makes it an excellent general-purpose tip, balancing gas consumption with sufficient thermal output to initiate cuts rapidly on dirty or rusted plate without overheating the workpiece.

Compatibility is key for industrial MRO environments. The MC40-4 is designed to fit a specific range of Smith Equipment cutting attachments and torches, including the MC505, MC509, CC509P, AC309, and DG109A. It is not compatible with standard Victor or Harris style torches, ensuring that safety and performance standards are maintained within the Smith equipment ecosystem. The tip's seats are precision-machined to ensure a leak-proof seal within the torch head, minimizing the risk of flashbacks and gas wastage.

Maintenance of the MC40-4 is straightforward due to its separable design. Operators can disassemble the outer shell to clean the splines of the inner member, removing carbon buildup and slag that can distort the flame pattern. This serviceability extends the operational life of the consumable, providing better long-term value in high-volume fabrication shops.