What does the tip number mean?

The tip number indexes the orifice size. Smaller numbers (0, 00) are tiny orifices for thin material; larger numbers (3, 4, 5) have bigger orifices that pass more gas to cut or heat thicker steel. Manufacturers like Victor, Harris, and Thermadyne number their tips on similar scales.

Why must I never exceed about 15 PSI on acetylene?

Acetylene becomes chemically unstable and can decompose explosively above roughly 15 PSI in the free state. Always keep the acetylene regulator at or below 15 PSI. The chart never recommends acetylene pressures above this safety limit.

What is a neutral flame?

A neutral flame has balanced oxygen and acetylene, shown by a single sharp inner cone with no feathery secondary cone. It is the standard for cutting and most welding. A carburizing (excess acetylene) flame shows a feather; an oxidizing (excess oxygen) flame is shorter and hissing.

Do cutting and welding use the same tips?

No. Cutting uses a cutting attachment with a center preheat-and-oxygen tip designed to deliver a high-pressure oxygen stream that burns through the steel. Welding and heating use single-orifice tips that mix the gases for a soft flame. Always match tip type to operation.

Are these pressures exact?

They are manufacturer-style starting points. Exact pressures vary by tip brand, hose length, and torch model, and should be set with the torch flowing, not static. Always consult your tip manufacturer's chart and adjust for a clean, stable flame.

Oxy-Acetylene Tip Size & Pressure Chart

Choosing the right oxy-acetylene tip and setting safe regulator pressures is the difference between a clean cut and a torch that pops, sputters, or never severs the plate. This interactive chart matches steel thickness to a Victor-style tip number for cutting, welding, or heating, and gives starting oxygen and acetylene pressures, while keeping acetylene safely at or below 15 PSI.

How it works

Each operation has its own tip-versus-thickness table derived from manufacturer charts. Thicker steel needs a larger orifice tip and higher oxygen pressure to push the cut; acetylene pressure rises more slowly and is always capped:

tip number   = lookup(operation, thickness)
oxygen PSI   = rises with thickness and tip size
acetylene PSI= rises modestly, never above ~15 PSI (safety limit)

Cutting uses a cutting attachment with a preheat ring plus a high-pressure oxygen jet; welding and heating use single mixing tips for a soft flame. The tool always reminds you to set a neutral flame for cutting and most welding.

Example and notes

For cutting 1/2 in mild steel, a typical setup is around a #1 to #2 cutting tip with roughly 30 to 40 PSI oxygen and 5 to 7 PSI acetylene. Thin 16-gauge sheet drops to a #000 to #0 tip with low oxygen and a few PSI of acetylene to avoid blowing through. Always purge hoses, set pressures with gas flowing, and confirm a sharp neutral inner cone before you touch metal. Never run acetylene above 15 PSI, and keep a striker, not a lighter, at hand.