A coupler for a helical pile system is described. The coupler includes at least two sections of square tube. A first section is nested within and affixed to the second section. The first section may further include an inner width by which the first section is configured to receive two pieces of rectangular bar stocks of a helical pile system. The at least two sections each include at least two pairs of aligned through holes, for receiving first and second bolts. By the first bolt and second bolts, the two pieces of rectangular bar stock may be coupled. The first section may thus transfer torsion between the two pieces of rectangular bar stock, such as when screwing the helical pile system into the earth.