The important thing to know about tapping a thread into a hole is you don't just screw the tap in.
If you do, it will often lock up and break off in the hole.
The proper way to screw the tap in is to first make sure it is pointed exactly in the direction of the hole.
Then, applying a light pressure to force it to start into the hole, rotate it about 2 to 3 turns.
Then, turn it about 1/2 turn backwards. Stop turning it. Turn it so it again screws into the hole until you feel resistance.
Then, turn it into the hole another 1 to 1 1/2 turns. Back it up 1/2 turn. Screw it in until resistance is felt and then turn it in another 1 to 1 1/2 turns. Back it out.......
Keep this up until the thread is formed to the depth desired.
The reason for this backing it out routine is as the tap is cutting it is making metal chips.
By backing the tap off 1/2 turn it will break off these chips and allow them to fall free of the cutting edges.
When tapping aluminum about any light weight oil will lubricate the tap but if you are threading steel use a "thread cutting oil" that is specifically made for this. The oil contains sulfur and a few other things to keep the steel chips from welding themselves to the tap causing it to break.