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How to drill plexiglass without cracking?

Do you want to drill plexiglass without cracking it? It might seem unreal, but let me tell you, various ways can help you drill these glasses without harming the material. I tried a few of these ways, and they worked well for me. Read along to get yourself familiar with the drilling techniques.

The best way to drill into plexiglass without cracking is to begin drilling with smaller bits first. The critical point is that you need to go as slowly as possible to avoid heating the plexiglass as it cracks easily due to increased friction. Keep on using bigger bits each time you drill into it until you get the desired size of the hole. See how simple yet effective this trick was?

Whats a plexiglass and why it cracks while drilling?

Plexiglass, also known as acrylic, is an alternative to the glass material. It can serve many purposes where a light weighted, and weather-resistant material is required. You can reshape the plexiglass effortlessly by applying heat to it.

However, due to its brittleness, it has greater exposure to scratched and is at high risk of cracking. It happens because when drilling, it tends to heat up quickly and gets fractured in no time. The extreme force that comes while drilling increases the friction, and thus the plexiglass expands due to the heat.

So if you are going to drill into plexiglass, make sure you keep a calm hand on the drill to avoid the melting of the glass.

Drill Bit to use for drilling into plexiglass without cracking

Here is a list of drill bits that you can use on your plexiglass to get a perfectly shaped round hole without even a tiny crack.

Plastic Drill Bits

Plastic drill bits are a way to go for drilling into the plexiglass. These drill bits come with metal ground flukes with 90-degree points and a 0-degree rake. The plastic drill bits can drill the plexiglass layer by layer and provide enough range of diameters for your ease.

Step Drill Bits

These drill bits do a great job when drilling into the plexiglass. You can acquire almost any size of holes with the step drill bits starting from smaller to bigger. It would be best if you started by clamping the plexiglass with scrap wood at the back.

Please make sure the drill is at a slow speed and very little pressure is applied, and there you go; it’s that easy with a step drill bit to drill plexiglass without cracking.

You can exactly get your hands on one of these bits as they are available at almost any hardware shop.

Standard Twist Drill Bits

This one is one of the most common drill bits out there and can be used to drill holes in the plexiglass without worrying about getting it cracked. The standard twist bit uses an angle of 118 degrees, perfect for drilling different types of materials.

It comes in different shapes and sizes so that you can have a variety of options. Keep in mind, going slowly with low pressure is the key!

Spiral Drill Bits

A spiral drill bit is another excellent option for drilling into the plexiglass. All you need is a correct setup and make sure everything is perfectly aligned to get started. After drilling approximately 5 mm, deburr the hole with a countersink cutter to get a perfect finish.

Cone Drill Bits

Now, if you are looking for a drill bit to drill into some curved and thin types of plexiglass like corrugated sheets or tubes, a cone drill bit might work best for you. These drill bits are simple to use and readily available.

Other than these, you can also opt for drill bits such as a centre bit, a flat bit, a stepped bit, or even a hole-saw that can do the job. However, a hole-saw is most suitable if you require a giant hole and should be at a right angle while drilling.

Now that you know what kind of drill bits will work best for you, here are some that I found out to be extremely difficult to use for drilling into the plexiglass.

I would recommend you avoid using the same drill bit you used for drilling wood as most of them require a higher speed to work. For instance, a Spade bit or a Forstner bit must be away while drilling into the plexiglass.

Drill Machine for drilling into plexiglass

Choosing the right equipment also matters if you want things to go smoothly, and for that, a suitable drill machine matters just as much. Below is the list of drill machines that will prove to be the most ideal while drilling into the plexiglass.

Pillar Drilling Machine

I would suggest you go for a pillar drilling machine. It is a free-standing machine that lets you use an electric motor for rotating a bit with a range of speeds (essential for plexiglass drilling). It also consists of a handwheel which further makes drilling holes a lot easier.

Drill Press

A drill press is another most used drill machine that provides enough features to work with plexiglass material. It includes a built-in work surface, a chuck, and a drive motor to ensure 90-degree drilling. It also has varying spindle speeds for you to have precise hole sizes.

Handheld Electric Drill

A handheld electric or cordless drill lets you drill plexiglass without cracking due to its exceptional features. However, it mainly accepts drill bits of particularly 1/4″ or 3/8″ in diameter.

In addition to these, flexible shaft-type drills and lathes also prove to fit this drilling purpose.

General Precautions to avoid cracking while drilling into plexiglass

You never know when plexiglass can crack up while drilling; even if you are completely careful, you still need to follow specific techniques to ensure it doesn’t. For this reason, I have highlighted below the main precautions to avoid cracking while drilling into the plexiglass.

First things first, always remember to wear eye goggles when you are working with drills. Mark it as a pretty important step as it can protect your eyes from falling debris.

To add to it, before you start drilling into plexiglass, you should always clamp the material or put a piece of scrap wood below the plastic to ensure that it remains in place and avoid any cracks by providing good support.

Lubricating the drill bit is another vital thing to consider while drilling. Although you can use any oil or dish soap, a wd-40 proves to be an ideal spray for this purpose. The lubricant will keep the glass cool and prevent any heat from forming.

You can also put painter’s tape over the plexiglass as a protective layer before lubricating the drill bit. Try not to increase the size of a hole using a twist bit; this will jam the sheet and break it apart.

The next thing to consider is always to use very little pressure and use sharper drill bits with as slow a speed as possible so that the plexiglass is safe from melting due to friction.

How to repair plexiglass if it cracks?

Already got a crack in your plexiglass? Don’t worry, as it can get fixed easily with solvent cement. If you didn’t know, solvent cement is a solvent-type bonding agent that can weld the acrylic by softening it.

So to repair the plexiglass when it cracks, use a very considerable amount of the solvent over the crack line and let it stay there for a few hours. It is essential to leave it for that much time to build up the required strength. You can also use a plexiglass adhesive for this purpose.