In DIY stores, auto parts or electricity, you'll find pods that are used to crimp the power cables. These pods are usually 6mm to 0.5mm diameter.You can use as is (round) or change the shape.To change the shape use tweezers or a small hammer. For oval, insert a small square piece of iron in the tube and a hammer gently crush two opposite ends. Remove the square iron and you have an oval cutter. Since tips are aluminum, it is very easy to modify their forms. Many possibilities for a low cost!