20 2 preferably non driven with bottom roll 20 2 urged by conventional pneumatic means 20 4 toward the upper roll 20 1 with a selected force as best seen in fig1 socket body 1 is provided with tower portions or projections 1 2 extending above the top surface of the socket body projections 1 2 are provided between each of the apertures in a row as well as at the beginning and end of each row the upper surface of the socket body has a transversely extending surface 1 3 which acts as a seat for transversely extending surface portions 7 2 of the contact element the profile of the circumferential surface of upper roll 20 1 is configured in order to engage contact element portion 7 2 and ensure that it bottoms out on surface 1 3 of the socket body while a cut out portion 20 3 in the peripheral surface of the roll 20 1 avoids engagement with the projections 1 2 of socket 1 after ensuring that the contact elements are fully seated the bodies pass between two pairs of staking rolls the particular number of pairs used is a matter of choice depending upon the degree of deformation desired at each pair of rollers further as mentioned supra deforming surfaces other than rolls could be employed if so desired as shown in station 20 a first pair of rolls upper roll 20 5 and lower roll 20 6 is follwed by a second pair of rolls upper roll 20 7 and lower roll 20 8 the.