Drilling into metal comes down to four habits: hold the work firmly, mark the spot with a center punch, run the drill at a modest speed with steady pressure, and keep the bit lubricated and cool. Skipping any of these is how bits dull, wander or snap.
Choose the Bit and Set the Speed
Bits made for metal are designed to cut harder material than wood bits. Check the packaging for the metals it suits, because very hard steels may call for a different bit than soft aluminum or mild steel.
- Harder metal generally needs a slower speed. Softer metal can tolerate a bit more.
- Larger bits generally need slower speeds than small ones.
- Check the maker’s chart or manual for speed guidance on your drill and bit.
Hold It Down and Mark It
A spinning bit can grab thin metal and whirl it around, which is a common cause of cut hands. Never hold the piece with your fingers.
- Clamp the piece to a bench or hold it in a drill-press vise. Put scrap wood underneath so the bit has something to exit into.
- Mark the hole with a marker, then make a small dimple with a center punch and hammer. The dimple keeps the tip from skating.
- Wear eye protection, and tie back long hair and loose sleeves. Skip gloves near spinning bits, as they can catch.
Drilling Technique
- Place the tip in the dimple and begin slowly to cut a clean initial groove.
- Apply steady, firm pressure in line with the bit. You should see curled chips, not dust.
- Add a drop of cutting oil on steel now and then to cut friction and heat. Follow the oil maker’s label.
- Back the bit out from time to time to clear chips and let it cool.
- Ease pressure just before the bit exits, since that is when it can snag.
For large holes, drill a smaller pilot hole first and then step up in size.
Finish the Hole
Drilling leaves a sharp burr on both sides. Remove it with a larger drill bit twisted by hand, a deburring tool or a file. Wipe away oil and swarf, and handle edges carefully.
| Sign | What it usually means |
|---|---|
| Blue or smoking bit | Too fast or too little oil |
| Squealing | Dull bit or no lubricant |
| Bit wandering | No center punch dimple |
Do not drill into structural members, gas or water supply pipes, or anything electrical without a qualified professional and local code guidance.
FAQ
Do I need a drill press?
No, a hand drill works for many jobs, but a press holds the bit straight and is easier to control.
Why does my bit grab when it breaks through?
Thin metal can catch the cutting edges. Lighten pressure and clamp the piece firmly.
The Short Version
Clamp the work, punch the mark, drill slowly with oil and clear the chips often. Wear eye protection and follow your drill’s manual.