Work-Hardening

Why Stainless Steel Is Different Stainless steel is the material that causes the most tool breakage in my experience — not because it’s the hardest, but because it work-hardens and grabs the tool if you hesitate. I’ve watched operators who can drill aluminum all day snap a carbide gun drill inside the first inch of 304. It’s not a material you muscle through. Over the years I’ve drilled thousands of holes in three stainless grades: 304, 316, and 17-4 PH. They look similar on paper but behave completely differently under the cutting edge. This article is what I wish someone had told me before I broke my first $400 tool. ...

I have drilled more titanium deep holes than I care to count, and I learned the hard way that titanium is not “tough steel.” It is a different animal. The thermal conductivity is roughly one-fifth that of steel. The chips are not chips – they are razor-edged bands that carry all the heat out of the cut. The work-hardening rate is aggressive enough to ruin a new gun-drill in seconds if you let the tool rub instead of cut. Every fix I learned on steel had to be re-learned for titanium. This article covers the specific failure modes I encounter in titanium deep hole drilling and the adjustments that actually work. ...