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Grotnes Expanding logo


Grotnes full body, single or double ended Expanders size and/or form cold/hot a wide range of hollow components, such as cylinders, cones, squares and polysided shapes.  The part to be expanded is positioned around the outer forming dies.  As the cone moves the dies are pushed outward and stretch the metal part beyond its yield point and form the desired shape and size.  Applications range from small light gauge metal parts such as appliance housings, bearing retainer rings, blower and fan housings, metal containers including conical shapes, drums of all sizes 55 gallon and lower including ISO open head, to heavy jet engine rings, slewing bearings, flanges, motor and generator frames and pipe couplings.

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