Rocketarium Hydra Sandhawk Build Part 12, Vent Hole Drilling TIP

1/4" diameter vent holes are drilled in the booster side walls.
The instructions say to drill a 1/8" hole first then enlarge it to 1/4".

TIP: You can make a "drill" out of a 1/4" diameter brass tube.
The inside wall of the tube was filed to a sharp edge using a half round file.

This sharp edge works pretty well to cut a 1/4" hole through the tube wall.

Take an extra moment to center the tube before starting to drill.
Spin the tube until you start to scratch the outside layer. Remove it and check to be sure it is centered. If the circle is positioned correctly, continue the drill.
The tube will want to collapse in so go slowly. It's easier to drill a hole when you can apply some finger pressure on the inside tube wall. You can't reach the inside of the BT-60.
After drilling through the outside continue through the interior BT-50 engine tube wall.

Here's how the tube will look after drilling through both sides of both tubes.
We'll clean up and strengthen the edges in the next post.