This a jig that I made up for accurately gluing the arm sections of the Delta-Pi Reprap 3D Printer. It is made up of layers of 3mm MDF, laser cut to house the pivot sections, with a base part to set the length. All the layers are held together with 8 1/8"x25mm bolts. NOTE: In the picture the bottom layers are acrylic but that is not required it was just what material I had laying around. Fairly self explanatory, There are 2 layers of the pivot cut-outs on each side attached to 2 layers of base plate.