Drilling Best Practices Checklist: 25 Things to Do Before, During, and After

Good drilling is mostly habits. Consistent habits produce consistent holes, longer bit life, and fewer scrapped parts. This checklist covers the full cycle: before the cut, during the cut, and after.

BEFORE THE CUT (Setup)

1. Inspect the drill bit visually. Check for chipped lips, worn margins, and cracks. A damaged bit is a scrapped part waiting to happen.
2. Verify geometry matches material. Steel geometry on aluminum costs you in quality and bit life. Confirm point angle is appropriate.
3. Check chuck condition. Worn chuck jaws produce runout. Measure TIR at the bit shank — under 0.001" for precision work, under 0.003" for general work.
4. Clamp the workpiece properly. Never hold with your hand. Use a drill press vise, clamps, or a proper fixture. A spinning workpiece is a safety hazard and produces bad holes.
5. Mark the hole location precisely. Use a center punch for a divot that guides the chisel edge. A centerpunch on thin sheet is sometimes not needed — a spotting drill is better.
6. Use a spotting drill on precision work. A spotting drill starts the hole on-location before the jobber drill engages. This eliminates walking on the first contact.
7. Calculate correct RPM for material and diameter. Use SFM formulas — don't guess. Wrong speed kills bits fast.
8. Set feed rate appropriately. Too slow on stainless work-hardens ahead of the tool. Too fast on fragile materials chips the cutting edge.
9. Prepare cutting fluid for the material. Steel gets cutting oil. Aluminum gets light lubricant. Cast iron gets nothing (air blast only).

DURING THE CUT

10. Apply cutting fluid before starting. Not mid-cut after heat has built up — before, so the tool enters a lubricated zone.
11. Use a consistent, steady feed. Hesitation causes rubbing and work-hardening. Committing to the feed rate is especially important in stainless.
12. Peck cycle on deep holes. Peck at 1-2x diameter increments to clear chips. Packed flutes = broken bits.
13. Clear chips between pecks. Don't just reverse — let the chips clear before re-engaging.
14. Re-apply cutting fluid after each peck. The fresh exposure needs fresh lubrication.
15. Listen and feel for changes. A squeal, chattering, or increased feed pressure means something changed — stop and check.
16. Watch chip formation. Continuous, tightly curled chips are correct for most steels. Powder means wrong speed (usually too fast). Long stringy chips wrap and become dangerous.
17. Reduce speed and pressure at breakthrough. The bit becomes momentarily unsupported when the chisel edge exits. This is when grab and breakage happen.

AFTER THE CUT

18. Deburr every hole. A sharp burr on the exit side is a safety hazard and ruins mating surfaces.
19. Check hole size. Measure with a go/no-go gauge or calipers. Consistently oversize holes mean worn drill margins or runout.
20. Inspect hole finish. Rough walls or chatter marks are diagnostic: check bit condition, speed, feed, and workholding.
21. Inspect the drill after use. Evaluate wear before putting it back in the crib. A bit that barely made the job might need resharpening before the next one.
22. Return drill to proper storage. Not a pile in a tray — indexed or sleeved to prevent tip damage.
23. Log any problems. If the hole was difficult, note why. Pattern recognition in your drill log prevents repeat problems.
24. Set dull bits aside for resharpening. Don't mix them back with sharp inventory — they'll be grabbed by someone who assumes they're sharp.
25. Update usage count if tracking cycles. Know how many holes each bit has drilled if you're on a scheduled regrind program.

These 25 points cover the full drilling cycle. None of them are complicated. The shops that do them consistently produce better work with longer-lasting tooling than the shops that wing it.

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