What Kind of Drill Bit Do You Need for Plexiglass?

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Using a specialty drill bit can help finish your project neatly and safely.

Plexiglass is a clear, plastic, lightweight alternative to glass. Drilling holes in plexiglass can be challenging. Often the traditional drill bits, used for metal and wood, chip and crack the plexiglass while drilling through its surface. Specialty drill bits prevent the cracking and chipping. You can also alter traditional drill bits to work better with plexiglass.


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Plastic Drill Bits

Plastic drill bits can drill through plastic. These metal drill bits have ground flukes with 90 degree points and 0 degree rake. Plastic drill bits shave or scrape plexiglass, acrylic or plastic away layer by layer. These bits come in a variety of diameters at home improvement or hardware stores. If you are unable to find them locally, many online retailers sell them.

Diamond Dusted Drill Bits

Diamond dusted bits can drill through hard plastics. Manufacturers bond diamond dust coating to the exteriors of these bits . This dust enables the bit's cutting edge to remain sharp. The bits come with a 60 degree points and 0 degree rake. Diamond dusted bits are good for stack drilling or drilling multiple layers of plexiglass or plastic materials. These bits are a little harder to find in local hardware and home improvement stores. You may have to purchase them online.


Modified Drill Bits

Regular or traditional high speed bits can drill plexiglass if you modify them. To modify regular bits, grind the small flats on the bit's cutting edges. This will help the bit scrape away the plexiglass as opposed to grabbing and fragmenting the material. With the bit correctly modified, you will see two continuous spiral ribbons of plexiglass coming from the hole as you drill.

Tips For Drilling Plexiglass

To drill into plexiglass successfully, control your drill speed. The faster the drill, the hotter the bit gets. Hot bits will melt the plexiglass around the hole. Go slow. Retract your drill bit from the hole often to let it cool. Use a lubricant or liquid. Water or a water soluble oil works well. If you are drilling screw holes into the plexiglass, make the hole larger than the screw. This prevents the screw from forcefully grabbing the plexiglass and it gives the screw room to expand.