Why are volcanoes not found at transform boundaries?

The transform fault boundaries are not having the same characteristics as the convergent or divergent plate boundaries. The movement at the convergent and divergent plate boundaries is caused by pressure from below, thus vertical one, and also when they collide one of them moves diagonally downwards, or rather subducts. That leaves gaps at the plate boundaries and big cracks through which the magma can penetrate. At the transform boundaries it is a different situation. The plates engaged in this type of boundary are neither moving away from each other, nor they are colliding, but instead they slide past each other. By sliding past each other, the plates actually close in any gap that might have enables for magma to come out on the surface, so we don't see volcanoes along this type of boundaries. What is typical about the transform plate boundaries is the formation of faults that form because of the stress, and are parallel to the boundary.