Manhole rims can vary in size, wear unpredictably or even be out of round. American Highway Products’ pivoted turnbuckle feature adjusts to accommodate variances from provided dimensions of up to plus or minus 1/2 in. in diam. for a total of 1-in. diametric adjustment. The turnbuckle makes it easy for minimally trained workers—using a screwdriver as a lever—to apply 5,600 lb of pressure evenly around the entire circumference of the riser. This enormous force easily and permanently fits the riser to the existing frame.
AHP manhole risers