Stainless scrap often starts with a polished, glazed wall after a light rub—then the next drill engagement skates and burns.
This playbook covers work-hardening behavior in solid carbide drilling of stainless: why the next cut dies, feed/engagement mistakes, coolant and chips, and geometry/coating as secondary levers—without invented SFM charts or “best drill for 316” absolutes.
Why stainless work-hardens the next cut
Austenitic stainless can harden under plastic deformation and heat when the edge rubs instead of cutting. A glazed surface raises force on re-entry and shortens the stable window.
Material context: stainless steel · series framing: Choose carbide drill series by material · product family: Carbide Drill for Stainless Steel.
Feed and engagement mistakes that glaze the wall
- Dwelling at entry or peck bottoms
- Feeding too light so the edge rubs
- Stopping mid-hole without a plan to re-engage a hardened skin
- Excessive stickout that forces rubbing instead of cut — Stickout, runout & toolholders
Process-first setup (no universal tables pasted here): Carbide drill speeds & feeds (process-first).
Coolant and chip evacuation priorities
Heat and packed chips accelerate glazing and edge damage. Confirm coolant actually reaches the cut and chips leave the flute—through-coolant evaluation: When flood coolant is not enough. Breakage after glaze: Why solid carbide drills break.
Practical re-entry rule after an interruption
If the spindle stops mid-hole, do not assume the wall is still “soft stainless.” Re-entry into a glazed band is a common second-break trigger. Prefer a planned peck/retract that leaves a cuttable chip, or a controlled re-start strategy agreed on the trial sheet—not an improvised light touch that polishes the wall again.
Record whether breakage happened on first entry, after a dwell, or on re-entry. That single note often separates geometry blame from work-hardening blame.
Geometry and coating—without a catalog dump
Point geometry, edge prep, and coating can help after the cut is committed and heat is managed. They do not replace a stable feed. Discuss options against the drawing—Solid carbide drill geometry · Solid Carbide Drill—not a SKU waterfall.
When to RFQ custom vs only adjust process
Adjust process first when dwell, stickout, or coolant aim are obvious. RFQ a application-specific carbide drill when grade/hardness, depth, and production volume need a controlled concept—send exact stainless grade, hardness if known, depth, coolant, stickout/runout, scrap mode via Custom Cutting Tool RFQ.
Frequently Asked Questions
Can we copy internet SFM for 304/316?
Not as a substitute for grade, depth, and machine data on the RFQ.
Is coating the first fix?
No—stop dwell and rubbing first.
What to send?
Exact grade, hardness if known, hole depth, coolant, stickout/runout, failure mode → RFQ.
What note separates geometry blame from work-hardening?
Record whether breakage happened on first entry, after a dwell, or on re-entry.