Abstract: A mandrel assembly is utilized to cold work a hole in a structural member which is present in a confined area. A mandrel and sleeve are slipped through one end of the hole. The mandrel length is threaded so that a nut may be turned along its length. Between the nut and the structural member are jaws which retain the sleeve within the hole while the nut is turned. The outward end of the mandrel is fixed by means of clamping flats formed on the outward end so the mandrel may be drawn through the sleeve within the hole as the nut is tightened against the intermediately positioned washer and jaws.

Abstract: A portion of a hole drilled through various layers of structural material may be cold worked by forcing a mandrel through a sleeve lining the hole. In order to precisely fix the projection of the sleeve within the hole of one layer, the thickness is first determined by ultrasonic measurement. Then, a micrometer assembly is employed to project the sleeve outwardly from a tool nose piece by the dimension prceisely equal to the ultrasonically measured thickness. The present tool enables cold working of a hole within only one layer of material while avoiding disturbance of the hole continuation in other layers.