The process of supporting the molds is such that the bolts are passed through the molds, then the washers are placed at both ends and the distance between the molds is fixed by a rooster nut. This is done by twisting the rooster bead around the bolt thread. Double washers should be used where parallel pipes are used as backrests.
The two-pipe washer with its curves makes these pipes fit and there is no obstacle for the washer to rest on the mold.