Method for contracting a cylindrical body

A method of sealingly fitting an element to a hollow cylindrical body, which method comprises the steps of:

• providing a hollow cylindrical body containing an element inserted therein with a clearance therebetween,
• grasping said hollow cylindrical body from the outside thereof with a plurality of elongated grasping members arranged to surround said hollow cylindrical body, one end of each grasping member being fixed to a column member,
• providing a cylindrical drawing die having an opening at one end thereof, the inner bore of said die having a part thereof tapered in a direction extending away from said opening, wherein an inside diameter of at least a portion of said die which defines the tapered part of said bore gradually decreases as taken along the longitudinal axis thereof in said direction away from said opening,
• drawing said grasping members together with said hollow cylindrical body into said drawing die through said opening,
• applying a compression force to said hollow cylindrical body through the intermediary of said grasping members by drawing the grasping members through said portion of said drawing die to thereby diametrically contract said hollow cylindrical body into a sealed fit with said element contained therein,
• prior to said drawing, coating a brazing flux on one of an inside surface of said hollow cylindrical body and an outside surface of said contained element, and
• brazing said hollow cylindrical body to said contained element by applying a heat treatment thereto after said drawing is completed.