The MachinistPost Blog

Carbide is harder but brittle. Cobalt bends without shattering. In interrupted drilling — keyways, stack plates, castings with voids — toughness beats hardness. The complete comparison with speed and feed adjustments.

Stainless steel work-hardens instantly when the drill rubs instead of cuts. Cobalt grade, correct SFM (25–40), and aggressive feed are the three variables that determine whether you get a clean hole or a burned edge.

Drilling plastics seems simple until the hole melts or the part cracks. Each engineering polymer has different heat tolerance, chip character, and geometry requirements.

Titanium work-hardens aggressively and generates heat that destroys cutting edges. With the right cobalt grade, geometry, and 15 to 30 SFM discipline, HSS handles it.

Abrasion-resistant plate is some of the toughest drilling you will do with a twist drill. The right cobalt grade and geometry make a real difference.

Inconel, Hastelloy, Waspaloy — these materials push HSS drill life to its limits. Here is what changes.

How to maximize HSS drill life when drilling titanium alloys with the right speeds, feeds, and coolant.

The metallurgical mechanisms behind HSS drill wear and what they mean for reconditioning decisions.

The signals that tell you it is time to upgrade from standard HSS to cobalt for your application.

Choosing between HSS, cobalt, and carbide drill bits based on your material, volume, and budget.

The definitive comparison of HSS, cobalt, and carbide drill materials for real-world shop decisions.

What separates M2, M35, and M42 HSS grades and when each is worth the cost upgrade.

A complete breakdown of HSS grade designations and what each means for drill performance and cost.

What happens to drill coatings as they wear, how to recognize coating failure, and when it matters.

A guide to drilling superalloys with the parameters and tool specs that prevent catastrophic failure.

How drilling behavior differs between 304 and 316 stainless and how to adjust your approach for each.

How to drill stainless steel successfully with the speeds, feeds, coolant, and geometry that matter most.

Techniques and tooling for drilling rubber, foam, and elastomeric materials without tearing or distortion.

How to select and run drill bits in non-ferrous aerospace alloys including aluminum, titanium, and magnesium.

A practical survival guide for machinists who need to drill Inconel and high-nickel alloys regularly.

The challenges of drilling Inconel and nickel alloys and the parameters that keep tools alive.

The conditions that make drilling hardened steel feasible and the limits you should not push past.

Tool selection, geometry, speeds, and technique for successfully drilling hardened steel workpieces.

What it takes to drill hardened steel with HSS bits and when it is worth trying vs switching to carbide.