Image Number 4 for United States Patent #4968236.
Auxiliary or stub augers are used in conjunction with a convention auger machine that is used to form reinforced hollow cored slabs. They can be used to ensure consolidation of concrete above the cores particularly and relatively in large diameter slabs or can be substituted for one or more of the conventional core forming augers if a core or bore is not required in the slab at that location. The stub auger consists of a first portion having a non tapering shaft and a non tapering flight thereon. The second or downstream portion has a gradually reducing diameter shaft with the flight which continues from the flight around the first portion, decreasing in diameter to substantially zero at the extreme downstream end of the shaft.