Can You Drill Into Acrylic?

Yes — you can absolutely drill into acrylic. As one of the most workable thermoplastic materials available, clear acrylic sheet accepts drilling well when you use the correct bit and follow the right technique. The key word here is correct: acrylic behaves very differently from wood or metal, and treating it like either will almost always result in cracks, chips, or melted edges.

Acrylic (also called PMMA, plexiglass, or Perspex) has a thermal expansion coefficient roughly nine times that of metal. This means friction from a fast-spinning or blunt drill bit generates heat quickly, softening the material and gumming up the hole — or cracking the sheet outright. The good news is that once you understand how the material responds, drilling clean, precise holes becomes a repeatable and straightforward process.

This guide covers everything you need: which drill bits to choose, what speed to run, a step-by-step drilling process, and the most common mistakes to avoid.

Choosing the Right Drill Bit for Acrylic

Drill bit selection is the single most important factor in getting a clean hole. Here is how each type performs on acrylic:

If you are drilling frequently, invest in a set of bits specifically ground for plastics — they are widely available and make a noticeable difference in hole quality. For occasional work, a sharp step bit is the most forgiving option you can find.

One unconventional tip from experienced fabricators: for larger-diameter holes, try drilling in reverse after creating a pilot hole. The reversed bit generates friction heat gradually, effectively melting a smooth path rather than cutting aggressively. This can produce very clean results in thicker sheets.

Drill Speed: What RPM Should You Use?

Speed is the second major variable. Slower is almost always safer with acrylic. High RPM generates heat faster than the material can dissipate it, leading to melting, gumming, and stress fractures. Use the table below as a starting reference and adjust based on how the chip looks — clean curling chips indicate good settings; powdery or melted residue means slow down.

For very thick acrylic (above 15 mm), consider peck drilling: advance the bit a few millimetres, retract to clear chips, then advance again. This prevents heat buildup and keeps the hole walls smooth.

Step-by-Step: How to Drill Acrylic Without Cracking

Follow these seven steps for consistently clean, crack-free results:

1. Secure the sheet. Clamp the acrylic firmly to a stable workbench. Any movement during drilling dramatically increases the risk of cracking. Use a sacrificial piece of wood or scrap acrylic underneath to support the sheet and prevent tear-out as the bit exits.
2. Mark your drill point. Use a fine marker or a pointed scribe to mark exactly where you want the hole. For precision work, apply a small piece of masking tape over the mark — this reduces surface slipping and helps prevent the surface from chipping.
3. Apply masking tape. Cover both the top and bottom surfaces at the drill point with masking tape. This adds a protective barrier that significantly reduces chipping when the bit enters and exits the material.
4. Start with a pilot hole. Begin with a small pilot bit (around 2–3 mm). Place the tip at your marked point, apply gentle and steady pressure, and drill slowly. The pilot hole guides your larger bit and reduces stress on the surrounding material.
5. Enlarge to final size gradually. If your final hole is larger than 6 mm, work up through intermediate sizes rather than jumping straight to the target diameter. Each step removes material gradually and keeps heat low.
6. Clear chips frequently. Stop every 5–10 seconds to retract the bit and let chips fall away. This is especially important for thicker sheets where chips can pack into the flutes and generate friction heat.
7. Finish and deburr. Once through, remove the masking tape and inspect the hole edge. A fine-grit sandpaper or a deburring tool can smooth any slight roughness. Avoid using alcohol to clean drilled areas — it can cause stress cracking around the hole.

When mounting acrylic with screws or standoffs through drilled holes, note that the bolt hole diameter should be at least twice the bolt diameter. This clearance allows for the thermal expansion and contraction that acrylic undergoes — tightening a screw into an exact-fit hole is a common cause of cracking weeks after installation.

Common Mistakes and How to Avoid Them

Even experienced fabricators run into problems with acrylic drilling. Here are the most frequent issues and their solutions:

• Cracking around the hole. Almost always caused by a dull or wrong bit, excessive speed, or drilling too close to the edge. Maintain at least 15 mm from the sheet edge. Use a sharp plastic-specific or step bit and drop your RPM.
• Melted or gummy edges. This is heat buildup. Reduce speed, take shorter cuts, clear chips more often, and consider adding a small amount of water as a coolant for thick sheets.
• Irregular or oval holes. Usually caused by the sheet moving during drilling (poor clamping) or a loose drill bit in the chuck. Double-check both before starting.
• Tear-out on the exit side. Not placing a sacrificial backing material under the sheet. Always back the acrylic with a flat piece of wood or scrap sheet so the bit continues into something solid as it exits.
• Sheet cracking after installation. Over-tightening screws into undersized holes. Make holes larger than the fastener diameter and never fully tighten — leave room for material movement.

Safety Tips When Drilling Acrylic

Acrylic drilling is a low-risk process, but a few precautions make it safer and more comfortable:

• Wear safety glasses. Fine plastic chips and debris are generated even at low speeds. Eye protection is non-negotiable.
• Work in a ventilated area. While normal drilling produces minimal fumes, overheating acrylic can release irritating vapours. If you smell burning plastic, you are running too fast or too hot.
• Never use heat as a substitute for drilling. Heating acrylic to melt through it releases harmful gases including carbon monoxide and other toxic compounds. Always use a proper drill.
• Clean up carefully. Fine acrylic dust and chips are slippery. Sweep or vacuum — do not blow chips away with compressed air, as airborne particles are a respiratory irritant.

Getting clean holes in acrylic starts with sourcing quality sheet material. Consistent thickness and a uniform, stress-free composition make a significant difference in how the material responds to drilling. Explore our range of acrylic reeded glass and other specialty formats, or browse the full selection of acrylic products from Zhejiang Leasinder — manufactured to tight tolerances and available for custom sizing to suit your project requirements.