How to Drill Holes into Plastic Without Cracks

Drilling into plastic may seem simple. Unlike very hard materials such as brick and metal, plastic does not involve heavy-duty drilling. On the other hand, it is a brittle material that can easily crack or splinter if you do not drill it carefully. You need to choose the right drill bit and you need to follow a few basic guidelines to make sure that you drill smooth, clean holes without causing cracks drilling into plastic.

If you’re planning a home DIY project involving plastic, this guide will show you how to drill into plastic without the risk of cracks or splinters.

Drilling into Plastic With no Cracks

To drill into plastic with no cracks, splinters or ragged edges, it helps to know what not to do. Here are a few mistakes to look out for if you want to avoid cracks in plastic. 

Using the wrong bits

The first mistake is using the wrong bits. Don’t assume that you can use any bit for plastic. Multi-purpose bits work on most plastics, however, harder plastics may need a tougher bit such as a Standard HSS bit. Using a wood bit on plastic is a very quick way to splinter the material. Likewise, a heavy-duty masonry bit will also cause cracks and damage. 

Drilling too quickly

Another mistake is to drill too quickly. Going too fast will increase the risk of overheating, which will melt the plastic. You will need to lower the speed even further as your bit exits the plastic. When plastic melts in some places, it can expand and contract, causing cracks and splinters that weaken the material. 

Not securing the material

Using a clamp to secure the plastic in place before you start drilling will ensure that the material stays still. If you do not do this, there is a greater chance of damaging the material. Clamp the material to your workbench or table, then add a piece of plywood below to form a barrier that will reduce the chance of chipping the surface of plastic at the bottom.

Making overly small holes

A common mistake is making holes that are just big enough to add screws. As plastic contracts and expands, the hole will need to be big enough to keep screws in place. Holes that are too small will expand too much, causing stress on the material. Make a hole that is slightly bigger than needed to allow for this expansion.

Drilling without lubrication

This is a common mistake when drilling most materials. With plastics, lubrication helps to prevent overheating. When your drill starts to overheat, plastic starts to melt. This will very quickly lead to splinters and cracks. Plastic shavings can gum up and form ragged edges, which is another reason to lubricate the bits and clear out debris as you work. 

Ruwag offers a selection of high-quality drill bits for every material, from plastics to metal and masonry.

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