Drilling plastic
Many constructors chose plastic project boxes to house their creations as they are fairly cheap, robust and easy to drill and cut with only a few basic tools.
However, drilling larger holes greater than 2 or 3 mm requires a bit of care.
The problem is that if you apply too much pressure to the drill, or the bit is too sharp, the bit can suddenly grab the plastic and snag. This can cause the plastic to be suddenly dragged up the bit causing odd shaped holes or even cause the plastic to split or fracture. This is quite likely when drilling the thin plastic lids from project boxes. You can also hurt yourself as the plastic can be literally ripped out your hand, it then spins around as it's now stuck to the drill bit and ends up usually cutting the back of your hand. As if the pain and blood all over the place isn't bad enough, the hole is now even more deformed or the piece completely ruined.
You have to apply light pressure and take it very slowly but even so, the larger the hole the more likely it is to snag.
However one really nice trick is to use a cone cutter.
However, drilling larger holes greater than 2 or 3 mm requires a bit of care.
The problem is that if you apply too much pressure to the drill, or the bit is too sharp, the bit can suddenly grab the plastic and snag. This can cause the plastic to be suddenly dragged up the bit causing odd shaped holes or even cause the plastic to split or fracture. This is quite likely when drilling the thin plastic lids from project boxes. You can also hurt yourself as the plastic can be literally ripped out your hand, it then spins around as it's now stuck to the drill bit and ends up usually cutting the back of your hand. As if the pain and blood all over the place isn't bad enough, the hole is now even more deformed or the piece completely ruined.
You have to apply light pressure and take it very slowly but even so, the larger the hole the more likely it is to snag.
However one really nice trick is to use a cone cutter.
If you shop around, search Ebay etc you can usually pick up a set of these fairly cheaply. Using them for plastic means they don't need to be the best quality and a set like those above should last you years. Cone cutters are NOT the same as tank hole cutters that have serrated teeth along the cutting edge. These do work with plastic but you have to be really careful when using them.
Cone cutters as the name implies are conical and available as step cutters; as shown above, or as a single tapered step less cone. Step less cutters can cut a hole of any size but they are harder to use if you need to drill holes of a precise size.
Typically each "step" in the cone is 1mm or 2mm larger than the previous. Because of their cutting action they don't snag the plastic and you can drill beautiful holes time after time if you take it slow. Cone cutters are best used with a pillar drill but you can use them with a hand drill if you're carful.
The other nice feature of these is that they tend to slightly counter-sink the hole for you. This removes any burr that may have formed and in fact you will usually get almost no burr even on the underside.
Don't let the cone get too warm though else the plastic will start to stick; you can see this on the centre cutter in above picture. However drilling a couple of holes in a piece of scrap aluminium was also a good way of cleaning off melted plastic.
Cone cutters as the name implies are conical and available as step cutters; as shown above, or as a single tapered step less cone. Step less cutters can cut a hole of any size but they are harder to use if you need to drill holes of a precise size.
Typically each "step" in the cone is 1mm or 2mm larger than the previous. Because of their cutting action they don't snag the plastic and you can drill beautiful holes time after time if you take it slow. Cone cutters are best used with a pillar drill but you can use them with a hand drill if you're carful.
The other nice feature of these is that they tend to slightly counter-sink the hole for you. This removes any burr that may have formed and in fact you will usually get almost no burr even on the underside.
Don't let the cone get too warm though else the plastic will start to stick; you can see this on the centre cutter in above picture. However drilling a couple of holes in a piece of scrap aluminium was also a good way of cleaning off melted plastic.