Clean a 1- or 2-liter plastic soda bottle. Soak it in soapy water, remove the label and rinse.
Use the razor blade, knife or drill to make holes in the bottle for the dowels. Create the holes in pairs that align at the same height and are located on opposite sides of the bottle. Alternate the placement of the holes so that the perches would end up on various sides of the bottle.
Insert the dowels through the holes, leaving some length on each side of every dowel outside the bottle to serve as perches. Adjust the dowels so that each perch has about the same length.
Use the knife, razor blade or drill to create one feeding hole under each perch. Each hole should measure 1/4 inch in length and 1/8 inch in width. The feeding hole would allow finches to take thistle seeds out of the feeder, but prevent the seeds from spilling out.
Use a knife, drill or razor blade to create a small hole at the bottom of the bottle, measuring about 7/16 inch in diameter.
Insert the metal eye screw through the hole at the bottom of the bottle.
Loop the wire around the eye screw and tie it. Affix the other end of the wire to a tree or a pole where you want to hang the feeder. When in place, the feeder hangs with the bottom of the bottle as the top of the feeder.