How to cut square/triangle holes in ABS project boxes

Step 2 The hot knife tip

Upon viewing the hot knife tip you can see that it is wedge shaped. This isnt quite what we need. By using the grinding tools however we can grind down the wedge as shown in the first photograph until we have a flat blade. We keep the pointy end of the wedge as it is useful when making the first insertions into the plastic.

The first tip shown here is half way done. The next two show the complete(ish) job.

This is good for large hole but for small ones you will need to grind down the blade thinner.