Can You Drill Acrylic

Acrylic is one of those materials that looks forgiving but punishes impatience. One wrong move — the wrong bit, too much speed, no cooling — and a clean sheet turns into a spiderweb of cracks. The good news? Drilling acrylic cleanly is absolutely achievable, even for beginners, as long as you respect the material’s quirks.

This guide covers everything from bit selection to speed settings, cooling tricks, and common mistakes that ruin otherwise perfect projects.

What Makes Acrylic Different to Drill

Acrylic (also called Plexiglas, Perspex, or PMMA) is a thermoplastic. That single word explains almost every challenge you’ll face when drilling it.

Unlike wood or metal, acrylic melts rather than cuts when friction gets too high. The heat generated by a spinning drill bit softens the material around the hole, causing it to grab, crack, or leave a rough, melted edge. It’s a bit like trying to cut butter with a warm knife — technically possible, but messy unless you know what you’re doing.

Acrylic also has low thermal conductivity, meaning heat builds up fast and stays concentrated right where your drill bit contacts the sheet. This makes cooling and feed rate critical factors, not optional considerations.

The Right Drill Bits for Acrylic

Standard Twist Bits (Modified)

Standard high-speed steel (HSS) twist bits can work on acrylic, but they need modification. The typical 118° point angle is designed for metal and tends to grab aggressively into acrylic. Grinding the tip to a 60°–90° point angle with zero or slightly negative rake reduces that grabbing tendency significantly.

Purpose-Made Acrylic Bits

These are the smart choice. Acrylic-specific drill bits feature:

• Polished flutes to reduce friction
• Modified cutting angles to shear rather than scrape
• A geometry that clears chips efficiently without melting them back into the hole

Brad-Point Bits

Brad-point bits work reasonably well on thinner acrylic sheets (under 6mm). The center spur keeps the bit from wandering, which is a genuine advantage when precision matters.

What to Avoid

Speed Settings: The Goldilocks Problem

Drill speed is where most people go wrong. The instinct is to go fast — get through the material quickly before heat builds up. With acrylic, that logic backfires completely.

Lower RPM is almost always better. High speed generates the friction-heat that melts thermoplastics. A slower, steady feed rate lets the bit shear cleanly through the material without overheating the contact zone.

Recommended Drill Speed by Thickness

As a rule: thicker acrylic = slower speed. The larger the hole diameter, the lower the RPM should go as well, since the outer edge of the bit travels faster at the same RPM.

Step-by-Step: How to Drill Acrylic Correctly

Step 1 — Mark and Secure the Sheet

Use a felt-tip marker or vinyl masking tape to mark your drill point. Never use a metal scribe — it creates micro-cracks in the surface that propagate under drilling stress.

Clamp the acrylic sheet firmly to a wooden backer board. This backer does two important jobs: it supports the material right up to the exit point, and it prevents the classic blow-out crack that happens when the bit punches through unsupported plastic.

Step 2 — Keep the Protective Film On

If your acrylic came with a protective paper or film coating, leave it on while drilling. It reduces surface scratching and provides a little extra support around the hole site.

Step 3 — Start with a Pilot Hole

For holes larger than 6mm, always start with a small pilot hole — around 3mm diameter. This gives the larger bit a center to follow and dramatically reduces the lateral force that causes cracking.

Step 4 — Drill at Low Speed with Light, Steady Pressure

Set your drill to the appropriate RPM from the table above. Apply light, consistent downward pressure — don’t force the bit. Let the cutting edge do the work. Forcing generates heat; patience generates clean holes.

Step 5 — Cool the Bit Regularly

Every few seconds on deeper holes, withdraw the bit to clear chips and let heat dissipate. For production work or thick sheets, a small amount of cutting fluid, water, or compressed air directed at the bit keeps temperatures in check. Even a damp cloth pressed briefly to the drill site between passes works well.

Step 6 — Support the Exit Side

As you approach breakthrough, ease off on pressure significantly. The last millimeter or two is where most cracks originate — the bit pushes through rather than cuts, and unsupported acrylic cracks radially from the hole edge like a dropped windshield.

Cooling Methods: A Quick Comparison

Common Problems and How to Fix Them

Cracking Around the Hole

This is almost always caused by one of three things: too much speed, drilling too fast through the material, or no backer board support. Slow down, add a backer, and ease off pressure near breakthrough.

Melted or Rough Hole Edges

Melting is a heat problem. The bit is either too dull, spinning too fast, or both. Replace the bit, reduce RPM, and cool more frequently.

Bit Wandering on the Surface

Acrylic’s hard, smooth surface gives drill bits nothing to grip. Always start with a center punch mark using tape (not metal) or use a brad-point bit to keep the tip exactly where you want it.

Chipping on the Exit Side

Almost always a backer board problem. A solid piece of scrap wood clamped tightly against the back face eliminates exit chipping almost completely.

Drilling Large Holes in Acrylic

When you need a hole larger than about 20mm, a standard twist bit is no longer the right tool.

Hole saws work on acrylic but require very low speeds (under 300 RPM) and frequent cooling pauses. Use a bi-metal hole saw rather than a carbon-steel version — it stays sharper longer and generates less friction heat.

Step drill bits are excellent for incrementally sizing up holes in thinner acrylic. Their progressive cutting action reduces shock and grabbing compared to plunging a large bit directly into the sheet.

Fly cutters (used on a drill press, never a handheld drill) allow very precise, clean large holes — but they demand a stable setup and low speed.

Drilling Thick Acrylic Blocks vs. Thin Sheets

The approach shifts meaningfully between a 3mm display panel and a 25mm acrylic block.

Thin sheets (under 6mm) are more prone to cracking from flexing. The material can bow away from the bit mid-drill if not well-supported. Use a full-surface backer board, not just clamped edges, and clamp close to the hole site.

Thick blocks are more forgiving of cracking but generate far more heat due to the extended contact time. Peck drilling — drilling in short plunges, withdrawing to clear chips — becomes essential. Think of it like drilling into hardwood: steady rhythm, regular chip clearing, patient progress.

Safety Considerations

Acrylic chips are surprisingly sharp and can travel fast. Always wear safety glasses — not just safety goggles, but proper impact-rated eyewear. Acrylic dust from drilling is also a mild irritant; a basic dust mask is worth wearing in enclosed spaces.

Secure loose clothing and keep hair tied back around rotating drill bits. And never hold acrylic sheet freehand while drilling — even a momentary grab can spin the sheet or crack it unpredictably.

Key Takeaways

• Low RPM is critical — acrylic melts from friction heat, so slower speeds produce cleaner holes than high-speed drilling.
• Always use a backer board — unsupported acrylic cracks at the exit point almost every time without one.
• Purpose-made acrylic bits outperform modified twist bits, especially for production work or precision holes.
• Peck drilling and regular bit withdrawal prevent heat buildup in thick sheets and deep holes.
• Start with a pilot hole for anything over 6mm — it eliminates the stress that causes radial cracking.

Frequently Asked Questions (FAQ)

Can you drill acrylic with a regular drill?
Yes, a standard handheld drill works fine on acrylic as long as you use the correct bit and keep RPM low. Variable-speed drills are preferable because you can dial down to 500–1,000 RPM. The drill itself matters less than the bit geometry and your technique.

What is the best drill bit for acrylic sheet?
Purpose-made acrylic drill bits with polished flutes and modified cutting angles give the cleanest results. If those aren’t available, a standard HSS twist bit with its tip reground to a shallower angle (around 60°–90°) works as a reliable substitute.

Why does acrylic crack when I drill it?
Cracking during drilling is almost always caused by heat buildup, excessive pressure near breakthrough, or lack of backing support. Reducing drill speed, using a sharp bit, and clamping a backer board behind the sheet eliminates cracking in most cases.

How do you drill a large hole in acrylic without cracking it?
Use a hole saw at very low RPM (under 300), cool frequently, and keep the sheet fully supported. Starting with a pilot hole at the center point and increasing size incrementally with a step bit is an even safer approach for holes between 20mm and 50mm.

Can you drill acrylic without a drill press?
Absolutely — a handheld drill drills acrylic successfully with good technique. A drill press does offer more control over speed and vertical alignment, but it’s not required. What matters most is clamping the work securely and maintaining consistent, light pressure.

How do you prevent melting when drilling acrylic?
Keep drill speed low, use a sharp bit, withdraw periodically to let heat dissipate, and apply light cooling with compressed air or a small amount of water if needed. Melting is purely a heat problem — solve the heat, and you solve the melting.

Can you drill acrylic with a Dremel or rotary tool?
A Dremel can drill small holes in acrylic using appropriate cutting bits, but control is harder due to the high default RPM of rotary tools. If using one, reduce speed to its lowest setting and use a very light touch. For anything precision or larger than about 4mm, a variable-speed drill gives better results.