adhesivedrillglassplastic
I have a sheet of styroglass, which I assume by the name to be a clear polystyrene.
I want to drill some M4 holes into it, which are about 2.5cm separated from each other.
However, I only have drillbits for wood and stone here. Will I be able to dill the holes with these or do I risk to crack the material? Should I go for another type of dillbit or just use strong glue?
Buy a self centering dowel drilling jig. Lee Valley has them, as will virtually all wood working supply sources, Rockler, for example.
The jig clamps to the end of your board, and then you drill through a hardened drill guide into the board, using a hand drill. These dowel jigs used to be much more common in the days before biscuits, pocket screws, etc.
The scope of your project requires an equally large scope of preparation. Swap out the ladder for a scaffold system. Replace the hand drill with, at a minimum, a drill jig to keep alignment while you drill. Use drill bits designed for drilling plastic to prevent cracking. Your emphasis on avoiding splintering/cracking increases the importance of proper drill bits. Using such a small diameter drill bit also increases the chance of snapping a bit in the hole. With a combination of scaffolds, a drill jig and proper bits, you may be able to accomplish your goal.
You suggest that the holes need not be perfectly straight, but a jig will enable you to drill in a safe manner to avoid snapping a bit.
A quote from a plastics web site:
Plexiglass, Lexan, Plastic Drill Bits These are the bits you need for drilling Plexiglass, Lexan polycarbonate, PETG, and other clear plastics. The special tip design carves through the plastic (not for use with wood or metal).
It takes a special drill bit to properly drill through Plexiglas, Lucite, Acrylite, or Perspex acrylic sheet. Ideal for Lexan, Tuffak or Makrolon polycarbonate sheet. Special 60 degree angle. Not recommended for wood or metal.
These are specially ground flukes with a 90° point for drilling holes in acrylic plastics including, Plexiglas®, Lucite® and Acrylite® materials. Metal drill bits will not work as they are made to bite into the metal as they are pushed into it. If they are used on acrylics they will chip and cause other damage to the plastic.
When drilling holes for screws, you must make the hole larger than the screw itself to allow for expansion and contraction of the material. If not you will cause stress cracks at the hole and they will spread! Always have a backer board behind the plastic sheet - most problems happen when you punch through the back side. The design of these bits helps prevent that!
Bits for cutting plastic have a shallower angle to the tip as well as less aggressive cutting edges. The one in the photo below shows it is nearly a scraping edge rather than a cutting edge:
Best Answer
Clear polystyrene appears to be a type of plastic, so I would say a wood drill bit should work. However, be careful about heat - you dont want to melt it. Take a break to let the bit cool if its starts getting hot.