Electric Vacuum Pen From Aquarium Air Pump.

Step 25: Spacing Of The Needle.

Most inflation needles have a hole on the side as well to make sure they can inflate the ball   I don't want that going past the tip of the nose cone.  I actually want it sealed up.  I've seen some needles that don't have that hole and if you could find one of those that would be best.  But we can still work with this.  I have some play between the nose cone and the needle that I want to tighten up.  So on my pen I wrapped around one layer of electrical tape to cover up the hole and to get a snug fit in the nose cone. before gluing it in.  Or if you don't care about having an ever so slightly larger opening at the end of your pen, use your cut end out the tip.