Foredom's brass tips are easy to clean and change. They are a great improvement over the tips used on other models. You can alter the tips with a file or pliers and create your own custom shapes.
Diameter ~ 4mm.
Full range of Tips for use with the WC-1:

• Small Flat (WT-1)
• Straight Taper (WT-2)
• Knife (WT-3)
• Small Spoon (WT-4)
• Curved Taper (WT-5)
• Large Flat (WT-6)
• Large Spoon (WT-7)