Hole drilling

[Fantom]

What do you guys use to drill larger holes in styrene? Like 3/8 inch, normal drills tend to pull the plastic out of shape or tear.

[NOBLNG]

These work pretty good.

 

Edited July 26, 2023 by NOBLNG

[Leica007]

Another technique is to start with a smaller bit (2-3 sizes) to create a pilot hole. This will relieve stress on the plastic for the larger size.  Same principle as  the graduated bit that Noblng uses/shown.

[Bainford]

If I need a nice, clean hole, I usually drill a smaller hole and use a file to finish.

[Rick L]

Breaking the sharp leading edge of the drill on a sharpening stone will prevent the drill from grabbing and breaking through the plastic. But keep in mind this will also make the drill useless for steel. Working with plastics all of my life, I now have a full drill index of backed off drills. ? Whenever I need a sharp drill, I resharpen with a Drill Doctor.

 

[Ulf]

If there's room and it's a flat surface, you can clamp about 1/8 inch plasticard on both sides and drill through these incrementally larger.

[afx]

I use various shaped grinding or carving bits turn by hand in a pin vise.  I drill a small hole first and work slowly up to the final size hole I need.  A round rat tail file will also work for larger diameter holes.

 

[Jiml0001]

Speed is also a big problem.  Styrene melts at a pretty low temperature and if a drill bit is too fast, it will melt rather than cut.  If you see melted plastic on the tip of your drill bit, slow it down