Choose a Plastic Drill Bit by Material, Not Just the Label

For acrylic sheet, buy a drill bit specifically designed for acrylic—not an ordinary metal bit with a different coating. Its cutting geometry matters: ACRYLITE recommends a 60–90° point and a near-zero rake angle so the edge scrapes rather than grabs the sheet. For small holes in many other unfilled plastics, an appropriately sharpened high-speed steel (HSS) twist drill can be sufficient. ACRYLITE’s drilling guide and Boedeker’s plastic-machining guidance distinguish these requirements.

A “plastic drill bit” is a bit for drilling plastic, usually made from steel. Before choosing one, identify the plastic, required hole diameter and material thickness.

Match the bit to the plastic

Workpiece	Sensible starting choice	Important limitation
Acrylic, including PMMA/Plexiglas sheet	Dedicated acrylic-rated twist bit	A standard metal-cutting point can grab, chip or crack it.
Polycarbonate	Sharp HSS twist bit where the material supplier permits it	Do not assume every clear sheet is acrylic or requires acrylic geometry.
Unfilled PVC or ABS	HSS twist drill with geometry suitable for the particular plastic	“Works on plastic” does not establish suitability for every grade or molded part.
Thin acrylic sheet needing several hole sizes	Step drill within the sheet maker’s limits	ACRYLITE lists Unibit/Vari-Bit step drills for 1/8–1/2-inch holes in sheet up to 0.118 inch (3 mm), with maximum backing support.

The distinction is real: Plaskolite specifies standard high-speed twist drills for TUFFAK MG machine-grade polycarbonate, while Boedeker lists different rake and point-angle ranges for acrylic, PVC and ABS. Treat those as material-specific recommendations, not interchangeable settings. Plaskolite TUFFAK MG data sheet; Boedeker drilling guidelines. The thin-sheet step-drill limits come from ACRYLITE’s onsite drilling guidance.

What to check before buying

For an acrylic bit, look for published point and rake angles, not simply “HSS,” “cobalt” or “titanium-coated.” ACRYLITE recommends a 90° point for most of its sheet-drilling operations, with a 0–4° rake angle. A 60° point is also within its guidance. Those angles describe different features: the point is the included angle at the tip; rake describes how the cutting edge engages the material. ACRYLITE.

As one concrete option, TAP PlasDrill bits are listed as HSS with a 60° point and zero rake. That specification fits the acrylic geometry range above; it is not a guarantee of chip-free results. TAP also recommends keeping these bits exclusively for plastic to preserve their edges. TAP PlasDrill specifications.

Also check:

• Cutting diameter: choose it for the finished hole, not automatically for the screw’s nominal diameter.
• Shank diameter: it may differ from the cutting diameter; verify your chuck accepts it.
• Usable drilling length: the flutes must accommodate the hole depth and chip removal.
• Step length, if using a step bit: the target step must span the sheet thickness without the next diameter entering. See our step drill bit guide.

For occasional acrylic work, buying the correct single bit is a more straightforward choice than trying to regrind a metal bit’s point, rake and relief angles yourself.

Drill without cracking or melting

Use rotary drilling with hammer mode off, wear eye protection, and clamp the work securely rather than holding it by hand.

1. Back the hole with solid material. For acrylic sheet, place scrap acrylic, another thermoplastic sheet or MDF directly beneath it. Clamp the assembly so the sheet cannot flex or vibrate.
2. Start with controlled feed. Let the bit enter without forcing it. Reduce feed again near breakthrough so it continues into the backing without tearing the exit edge.
3. Clear chips from deeper holes. Withdraw the bit periodically—peck drilling—rather than allowing packed chips to rub inside the hole.
4. Manage heat. For ACRYLITE, the manufacturer recommends cooling when hole depth exceeds bit diameter, or when diameter is at least 1/2 inch. Use only a coolant compatible with the plastic, and keep liquids away from the drill’s electrical parts. ACRYLITE drilling procedures.

There is no useful single RPM for all plastic holes. Diameter, thickness, geometry and feed all matter. In acrylic, larger bits generally need lower spindle speeds. Feeding too slowly can also cause melting: the bit rubs instead of removing material effectively.

Use the hole and chips as feedback:

• Chipping: reduce feed, check backing and verify the bit’s rake angle.
• Molten chips or smeared hole walls: clear the flutes, reduce excessive RPM and check whether feed is too slow.
• Irregular holes: check for a bent or incorrectly ground bit, or drill/chuck runout.

These are the fault patterns identified in ACRYLITE’s troubleshooting guide. Stop and correct the setup rather than forcing the bit through.

For mounting holes, consult the sheet maker’s fastening guidance before drilling. Acrylic panels need allowance for expansion and suitable edge spacing; a clean hole alone does not make a sound fastening. ACRYLITE’s point-fastening guidance.