When creating a cake with several tiers, if the cakes have been covered in sugarpaste it is essential to use dowels to support the tiers, whether you are using cake pillars to separate the tiers or stacking them straight on top of each other.
For tiers that are stacked directly on top of each other, you can use plastic or wooden dowels. Measure and cut the dowels accurately to ensure that when they are pushed into the cake, they sit completely level with the cake surface. The dowels should all be the same size so that when the next tier is placed on top of the dowels, it is not only supported but it is also level. Use 4 dowels per cake, or 5 for a larger cake.
Place pillars in their required positions on the cake and push a wooden or plastic dowel through each pillar and continue to push the dowel through the cake until it hits the board. Take a ruler and rest it across 2 pillars at a time and, with a pencil, mark the dowel at the top of the pillar. Then move on to mark the other dowels, each time resting the ruler on 2 pillars (if you have 4 pillars you will need to move the ruler 4 times, with 3 pillars you will need to move the ruler 3 times).
Once all the dowels have been marked, carefully take the dowels out of the cake and re-mark them to match the highest pencil mark. Taking the highest mark will ensure that when the cakes are stacked, the pillars will not sink into the icing should the surface of the cake not be completely level. Use a hacksaw to cut the dowels to the highest mark then clean them and carefully push back into the cake in the same holes and place the pillars over the dowels.
Remember: Make sure all the dowels are cut precisely to the height of the highest pencil mark so that the cakes do not sink into each other.