Dakota
Years ago I made one. I used a 6' 2x10 and screwed 6 or 7 inch long 3/8" eye bolts into each end. 2 sets so I could stretch 2 strings at a time. At one end I run a treaded hook that is probably 8 or 10 inches long through one of the eyebolts and then add a couple large washers and a nut so that I can put a wrench on it and tighten it up. on the other end I add a stiff spring. I attach the string to the threaded hook and then to the spring. (depending on the lenth of the string, I sumtimes have to use a short peice of chane to make it reach the eyebolt.) I then put a wrench to the nut on the threaded hook and tighted the whole thing as far as it will go. A dacron string will usualy stretch an inch or two within a day and the jug makes it easy to twist the string up or down to get the correct lenth. Because the string sets about 3 or 4 inches off of the 2x10 it is easy to serve.