"Drilling is the process of cutting holes in a piece of material"
HOW TO CHANGE THE DRILLING SPEED
The speed at which the drill bit rotates can be changed. The speed at which the drill bit needs to rotate usually depends on the piece of material being drilled and the size of the drill bit.
SMALL drill bits usually require a fast drilling speed
LARGE drill bits usually require a slow drilling speed
The speed of the drill is changed by manually moving the belt across the pulleys shown in the photograph.
The image above shows a pulley system within the Pillar Drill Machine. Altering the pulleys will change the speed of the drill
HOW TO DRILL A LARGE HOLE IN A PIECE OF METAL
When wanting to drill a large hole in a piece of metal the following process must be followed:
Example - 10mm hole
1. Centre Punch the work piece
2. Use a small drill bit to begin the hole (3mm)
3. Increase the size of the drill bit and drill again (6.5mm)
4. Increase the size of the drill bit and drill again (10mm)
5. Process Complete
A large hole cannot be drilled in one go