In this paper we report on the development of micromachined filters for operation at terahertz frequencies. SU8, a negative photodefinable epoxy, is used to define arrays of high aspect ratio rods which are subsequently sputter coated in gold to form the filter. We fabricate and test a filter with a fixed period but variable diameter along the length of the array. By moving the array in the terahertz beam we demonstrate the ability to mechanically tune specific filter characteristics from a single device.