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Small brass cutting tip with threaded base and single orifice

Miller-Smith Equipment

Miller-Smith Equipment MC12-4 Cutting Tip Size 4

SKU CH-KWTW-KC1W2

Acetylene cutting tip for handheld torches, size 4, cuts 2 1/2 to 4 inch steel with 12 scfh preheat fuel flow and 65 psig oxygen pressure

  • TypeWelding Parts & Supplies
  • Cuts 2 1/2 to 4 inch steel with MC12-4 tip
  • Medium preheat flame suits acetylene handheld torches
  • 12 scfh acetylene and 14 scfh oxygen preheat flows
  • 249 to 320 scfh cutting oxygen flow for heavy sections
  • Compatible with AC309, CC509P, DG109A, MC505 and MC509 attachments

MC12-4 Cutting Tip for Acetylene

The MC12-4 is a one-piece cutting tip designed for handheld oxy-fuel torches running on acetylene. It is built for operators who need a size-4 tip to make straight cuts in steel plate between 2 1/2 in and 4 in thick. The tip belongs to the MC12 series and fits compatible Smith cutting attachments. It is not for welders using propane or propylene fuel gases, nor for automated machine torches.

Flow and pressure limits for the MC12 series

Preheat flow rates are fixed at 12 scfh for acetylene and 14 scfh for oxygen. Cutting oxygen flow ranges from 249 to 320 scfh depending on the thickness being cut. Fuel pressure must be set at 10 psig and cutting oxygen at 65 psig; exceeding these pressures can damage the tip or cause unstable flames. The tip cannot be used with cutting attachments outside the listed compatible models.

Installation and common issues

The tip threads directly onto compatible Smith attachments including the AC309, CC509P, DG109A, MC505 and MC509. Hand-tighten only; over-tightening with a wrench distorts the one-piece body and ruins the seal. The most frequent problems are carbon buildup in the preheat slots when pressures drift low, and flashback caused by running acetylene above 10 psig.

Highlights

  • Cuts 2 1/2 to 4 inch steel with MC12-4 tip
  • Medium preheat flame suits acetylene handheld torches
  • 12 scfh acetylene and 14 scfh oxygen preheat flows
  • 249 to 320 scfh cutting oxygen flow for heavy sections
  • Compatible with AC309, CC509P, DG109A, MC505 and MC509 attachments

Specifications

BrandSMITH EQUIPMENT
TypeWelding Parts & Supplies

Questions about this item

What does tip size 4 mean for the thickness I can cut?

Tip size 4 handles steel from 2 1/2 in up to 4 in thick with this tip series.

How do the 12 scfh acetylene and 14 scfh oxygen preheat rates translate on the bench?

Those flow rates set a medium preheat flame; expect 12 scfh acetylene and 14 scfh oxygen at the torch before you open the cutting lever.

What does the 65 psig oxygen pressure rating cap in practice?

The cutting oxygen pressure must not exceed 65 psig; higher pressure would push flow past the 320 scfh upper limit and distort the cut.

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