Rubber stoppers are used to seal glassware. However, sometimes you may want to insert some tubing or instruments into the glassware without removing the stopper. For this, holes must be made in the stopper.
The easiest way would be to drill through. Use your tool of choice, from hand drills to drill presses. Drill presses work quite well due to their stability and accuracy.
For drill bits, the following are some that will work:
Readily available, but may not create the smoothest hole. Also not the easiest to use.
These provide smoother holes than a twist bit.
These make some of the best holes. You can also substitute a leather punch or fashion your own core bit out of a metal tube.
- Freeze the stopper before drilling. The colder the better. Use dry ice or liquid nitrogen if available.
- Lubricate the drill bits and the stopper where you are drilling. Grease, oil, or hand soap would work. Be sure to wash out the holes afterwards.