Walter 4-40 NC High Speed Steel Plug Tap

Reliable Tapping for Fabrication and Repair

Every welder and fabricator knows the sinking feeling of a tap snapping off inside a critical part. It turns a five-minute job into an hour-long nightmare of extraction and repair. The Walter 4-40 NC Plug Tap is built to prevent exactly that scenario. Crafted from high-quality High Speed Steel (HSS), this tap is tougher and more resilient than the cheap carbon steel taps found in hardware stores. It is designed to bite into metal and cut clean threads without binding or breaking, giving you the confidence to tackle delicate threading jobs on expensive components.

The 4-40 thread size is common in electronics, small brackets, and precision instrument mounting. Because the diameter is small, the risk of breakage is inherently higher. Walter addresses this with a tap that has been hardened and tempered to handle the torque required to cut through materials like stainless steel and mild steel. The "Plug" style chamfer is the workhorse of the shop; it has enough taper to start the thread easily but is aggressive enough to thread close to the bottom of a hole if needed. It is the perfect all-rounder for your tool chest.

Whether you are fabricating a custom enclosure, repairing a stripped thread on a machine guard, or tapping holes in aluminum plate, this tool delivers professional results. The precision ground threads ensure that the screws you install will fit smoothly and hold securely. No more cross-threading or fighting with tight fasteners. For the best results, we always recommend using a quality cutting fluid, like Walter's Coolcut, to keep the tool cool and lubricated during the cut.

Don't let a stripped thread slow down your production. Keep a Walter 03A042 4-40 NC Plug Tap on hand for those moments when precision and reliability matter most. It is a small tool that makes a big difference in the quality of your finish work and the efficiency of your shop.