Drill Perfect Holes in Plexiglass Every Time!

 

Using Drill Bits Made Specifically for Plastics

When drilling plexiglass (acrylic sheet), using drill bits specifically engineered for plastics is the key to achieving perfectly round, chip-free holes. Unlike standard metal drill bits with a 118° or 135° point angle, plastic drill bits feature a sharp 60° tip angle, like this set from eBay, that gradually penetrates the material instead of aggressively wedging into it. This steep point geometry reduces thrust pressure and prevents the bit from grabbing as it breaks through the backside—one of the most common causes of cracking and starburst fractures in acrylic. This is why step bits are also useful for drilling holes in plexiglass,   For anyone working with cast acrylic, Lucite, or Plexiglas sheets, this specialized tip angle delivers superior hole accuracy, smoother edges, and dramatically less risk of stress fractures.

Equally critical is the zero rake (or neutral rake) cutting edge geometry. Standard twist drills for metal have a positive rake angle that “bites” into material, but acrylic is softer and more brittle than metals. A positive rake can pull the bit forward too aggressively, causing chipping, melting, or out-of-round holes. Plastic drill bits use zero rake to create a scraping action rather than a grabbing action, allowing controlled chip formation and steady material removal. This geometry minimizes heat buildup, reduces melting, and ensures the hole remains dimensionally stable and perfectly circular. For fabricators, sign makers, and artists seeking precision drilling in plexiglass, acrylic, or other thermoplastics, dedicated plastic drill bits provide the cleanest, safest, and most professional results.

Drilling Holes for Rivets and Threading Holes For Screws

Using drill bits designed specifically for plastics is especially important when preparing plexiglass (acrylic sheet) for rivets or threaded fasteners. When installing pop rivets through acrylic panels, hole geometry must be precise and stress-free to prevent cracking during compression. The 60° point angle and zero rake cutting edges found on plastic drill bits reduce grabbing and breakout, which is critical when drilling holes sized for 1/8", 3/16", or larger rivets. A clean, perfectly round hole allows the rivet body to seat evenly without creating radial stress fractures around the perimeter. This is particularly important in fabrication projects that combine acrylic with steel or aluminum panels, where uneven hole quality can lead to long-term cracking from vibration or differential expansion.

The same geometry is equally beneficial when drilling pilot holes for tapping threads in acrylic. Standard metal drill bits can create slightly oversized, chipped, or heat-distorted holes that compromise thread integrity. In contrast, plastic-specific drill bits produce dimensionally accurate holes with smooth internal walls, providing optimal engagement when cutting threads for machine screws. Because zero rake reduces heat buildup and prevents micro-cracking, the tapped threads are stronger and less prone to stripping. For fabricators, sign makers, and artists working with plexiglass, using the correct plastic drill bit ensures reliable rivet installation, cleaner tapped threads, and long-term structural integrity in acrylic assemblies.