Engraving metal is mostly about giving the bit a seat so it doesn't skate on the first touch. Stainless tags, aluminium pens and tool handles all take a clean line with a carbide burr and a steady rest — the trick is a center-punch dimple and starting the tool before it meets the surface. Here is the setup that keeps it put.
Key Takeaways
- Carbide burr for steel and aluminium; diamond for coated or anodised metal.
- Center-punch a dimple so the bit seats instead of skating.
- Steel 10,000–18,000 RPM; aluminium 12,000–20,000 RPM.
- Start the tool spinning before contact — slips happen in the first second.
Which bit should you use for steel versus aluminium?
Steel and aluminium both want a carbide burr, but the shape changes with the job. A pointed or tapered carbide on a 2.35 mm shank handles lettering on a stainless tag, while a ball-nose carbide suits broad shading on a tool handle. Coated or anodised metal is the exception: a diamond point cuts the surface layer cleanly, where carbide loads up within 30 seconds and starts to smear instead of cutting. Keep one burr for steel and one for aluminium. A 1 mm burr is the workhorse for most tags.
Match the tool to the size of the job. A slim pen body is easier to steady on a 30 mm tag than a full-size tool, and it keeps your fingers close to the point for fine control. Long steel strokes need sustained torque instead, because a tool that slows halfway through a stroke leaves a shallower line you cannot blend. A HARDELL Silver Essential 37000RPM Cordless Engraving Pen covers the fine work, and a HARDELL Orange Black Ultimate 155pcs Corded Rotary System holds power through a 150 mm stroke.
How do you stop the bit skating on metal?
Center-punch a small dimple where the line starts, and 0.4 to 0.5 mm deep is enough. The burr drops into the seat instead of wandering, and that first second is where almost every slip happens. For long lines, punch a dimple every 20 to 30 mm so you can restart cleanly if the bit lifts out of the groove. A spring-loaded punch keeps depth consistent across a run of tags. Punch on a steel plate, not on the bench, so thin tags do not bend. Keep the point sharp.
Body position does the rest. On a pen or a round handle, rest the heel of your hand on a wooden block so only the tool moves, and brace the workpiece against a fence clamped to the bench. A strip of masking tape along the intended line adds grip for the burr and shows the path you planned. Start the tool spinning before it meets the metal, every single time, and lift it spinning as well. Keep your elbows tucked in, because a floating arm wanders on long letters.
| Item | Bit | Speed (RPM) | Anti-slip trick |
|---|---|---|---|
| Stainless tag | Carbide burr | 10,000–18,000 | Center-punch dimple |
| Aluminium pen | Carbide burr | 12,000–20,000 | Light cutting oil |
| Steel tool handle | Diamond point | 10,000–16,000 | Center-punch dimple |
| Anodised tag | Diamond point | 15,000–22,000 | Masking-tape guide |
What speed and pressure give a clean cut?
Steel runs at 10000 to 18000 RPM with a light push, and aluminium wants a touch more, 12000 to 20000, because it is softer and clears chips better at speed. Listen while you cut: a high squeal means you are too hard or too slow, and a chattering rattle means the burr is skipping across the surface. Ease off pressure first, then adjust speed, and note the setting that worked on the template. Aluminium needs about half the pressure of steel, and any dial change takes two seconds to settle.
Feed rate matters more than most people expect. Aim for about 10 mm per second and let the burr cut at its own pace, because forcing it bogs the motor and tears the wall of the groove. On aluminium, one drop of cutting oil every 20 seconds keeps the flutes clear across a 50 mm stroke. Wipe swarf away before it packs into the letters, and work in 30 mm sections on long lines. A HARDELL Black Essential 37000RPM Cordless Engraving Pen gives the same control on a dark bench.
How do you engrave a round pen or tool handle?
Round work is a rotation problem rather than a carving problem. Wrap the barrel in a strip of masking tape as a guide line, then cut along the tape edge, keeping the tape flat and tight so it cannot creep under the burr. Rotate the pen in your hand while the bit stays fixed in space, so the surface turns under the burr instead of the tool tracking around a curve it cannot hold. Mark the start with a pencil dot, and let the tape take any stray scratches.
Take two light passes of about 0.3 mm instead of one deep gouge, because a single heavy pass on a round barrel always drifts downhill as the burr follows the curve. Support the far end on a padded block so the barrel cannot roll away. Check the ring under a lamp after the first pass, and rotate evenly. For long handles, a flex shaft keeps the weight off your wrist: a HARDELL Orange Pro 155pcs Rotary Tool Kit with Flex Shaft leaves only the slim handpiece in your grip.
How deep should you go, and how do you finish?
Go shallow first, 0.2 to 0.3 mm on pass one, then deepen to 0.5 to 0.8 mm on pass two, which is deep enough to hold paint and still catch the light. On thin tags under 1 mm, stop at 0.4 mm or you will cut clean through the metal. Depth that looks right under a bench lamp often reads shallow in daylight, so check the piece outdoors before you call it finished. Two passes also keep the burr cooler. Write the tag thickness on the template before you start.
Finishing is quick but not optional. Wipe the metal with a thin film of oil to show the cut and stop rust forming in the line within a day. On anodised tags keep the pressure minimal so you do not break the colour coat beyond the cut. Deburr the edges with a felt bob at 5000 RPM so the tag never snags on a pocket or a key ring. Re-oil bare steel every few months, and round sharp corners with the same bob before the tag goes in a pocket.
| Symptom | Likely cause | Fix | Target |
|---|---|---|---|
| Burr skates off the start point | No dimple on a dry surface | Center-punch a 0.5 mm dimple, start at 12000 RPM | First 3 mm of the line stays on the mark |
| Cut looks rough and chattered | Too little speed, too much push | Raise to 16000 RPM, feed at 10 mm per second | Groove wall reads even under 5x magnification |
| Aluminium loading up the burr | No cutting oil on soft alloy | One drop of cutting oil every 20 seconds | Flutes stay clear for a full 50 mm stroke |
| Anodised colour flaking at the cut | Diamond point pressed too hard | Near-zero pressure, two 0.3 mm passes | Colour edge stays intact within 0.5 mm |
Why does the line come out ragged, and how do you fix it?
A ragged or chattered line means the burr is skipping rather than cutting. The usual causes are speed below 10000 RPM, a dull burr, or a hand pressing harder than the flutes can clear. Raise the speed to 16000 RPM, halve your pressure and feed at about 10 mm per second, then check that the wall of the groove looks even under 5x magnification. Replace a burr after roughly 4 hours on steel, and suspect a bent shank when the chatter repeats at a fixed pitch.
Ragged edges also come from a loose workpiece. If the tag flexes even slightly, the burr digs in on one side of every stroke and lifts on the other, which is why the defect repeats at a regular pitch. Clamp it flat against a backing board, or bed it on double-sided tape over a steel plate, with a second clamp about 20 mm from the cut. To clean up a line that is already ragged, widen it by 0.5 mm with a fresh burr and re-cut the wall straight.
How do you lay out text and keep letter spacing even?
Measure the line before you cut it. Find the centre of the tag, divide the total text width by the number of letters and mark each cell lightly with a scribe, so a 40 mm tag with eight letters gives a 5 mm cell per character. Lettering spaced by eye always drifts by the third word, and working centre outward hides small errors better than left to right. Leave a 3 mm margin at each end, and space letters by their widest part rather than their centre.
Keep a consistent height by marking two parallel scribe lines for the cap height and the baseline, spaced to your intended letter height, and never crossing them. Light marks wipe off with alcohol once the burr has passed, and they also guide the burr on the first pass. Set the cap height to two thirds of the tag width. Tape a printed template in place for your first few tags, because freehand layout takes practice. A HARDELL Metal Advanced 6in Rechargeable Digital Caliper checks spacing to 0.1 mm between letters.
How do you clean metal and protect the engraving afterwards?
Clear the chips first. A nylon brush with a drop of degreaser removes swarf packed in the groove, and a hand blower gets the rest out of tight letters. Swarf left in a cut traps moisture, and on bare steel the line rusts from the inside out within a week, which no amount of wax will undo afterwards. Work over a tray so chips do not spread across the bench, and do this before any wax or paint. A brass brush works too, but never on an anodised surface.
Then protect it. Bare steel and aluminium want a thin coat of paste wax or oil reapplied every few months, while stainless can simply be left clean. Two thin coats of wax last about three months outdoors, and paint in a cut lasts about two years on a tag carried daily. For letters you want to read from across a room, rub acrylic paint into the cut, let it skin for 10 minutes, then wipe the surface with a solvent cloth so colour stays only in the recess.
FAQ
Why does my bit skate on steel?
The surface is slick and the burr grabs late. Center-punch a 0.5 mm dimple so the burr seats before you push, and start the tool spinning before it touches metal.
Carbide or diamond for metal?
Carbide burrs for raw steel and aluminium, diamond points for coated or anodised metal. Mixing the two only wears the bit and smears the coating around the cut.
How deep should I cut into metal?
Start at 0.2 to 0.3 mm and finish around 0.5 to 0.8 mm. Deep single cuts on steel are hard to control and usually break the line you planned.
Can I engrave a curved pen barrel?
Yes. Tape a guide line around the barrel, rotate the pen in your hand and keep the bit steady. Two passes at 0.3 mm give a clean, even ring.
Do I need cutting oil on metal?
A drop or two clears chips and cools the burr on steel and aluminium, leaving a cleaner line. Wipe the surface before you paint or wax the cut.
How do I stop the pen wandering on curves?
Pivot your wrist on a block so only the tool moves, keep speed above 12000 RPM and use near-zero pressure. Let the burr cut at its own feed rate.
How do I engrave a tag without a vise?
Bed the tag on double-sided tape over a steel plate and brace it against a clamped fence. It should not flex at all when you push sideways with light finger pressure.
What depth works for engraving I plan to paint?
About 0.5 mm gives paint somewhere to sit without colour bleeding past the line. Any shallower and the paint wipes straight out when you clean the surface.
Related Products
- HARDELL Silver Essential 37000RPM Cordless Engraving Pen
- HARDELL Black Essential 37000RPM Cordless Engraving Pen
- HARDELL Orange Black Ultimate 155pcs Corded Rotary System
- HARDELL Metal Advanced 6in Rechargeable Digital Caliper
