. The Bell System technical journal . Fig. —Examples of headed phosphor-bronze wire. The most recent development for wire supports involves the use of headedphosphor-bronze wires as worked out by A. W. Ziegler. In this procedureindividual wire lengths are cut and one end upset in a cold heading toolwhich provides a Uttle cone-shaped head with a base of about 22 mils asshown in Figure for 6-mil diameter wires. The head is carefully pre-tinned, leaving a small globule of solder at the end. Depending upon thesize of the crystal plate, globules of 1000, 3000 or 7000 cubic mils of solderar
. The Bell System technical journal . Fig. —Examples of headed phosphor-bronze wire. The most recent development for wire supports involves the use of headedphosphor-bronze wires as worked out by A. W. Ziegler. In this procedureindividual wire lengths are cut and one end upset in a cold heading toolwhich provides a Uttle cone-shaped head with a base of about 22 mils asshown in Figure for 6-mil diameter wires. The head is carefully pre-tinned, leaving a small globule of solder at the end. Depending upon thesize of the crystal plate, globules of 1000, 3000 or 7000 cubic mils of solderare used. The attachments are made in a wire soldering tool which attachesthe wires to both sides of the plate simultaneously. This tool is illustratedin Figure The prepared wires are fed into positioning guides, which PLATED QUARTZ CRYSTAL UNITS 249. 2 fe 250 BELL SYSTEM TECHNICAL JOURNAL are aligned with respect to the crystal plate, which is properly located andheld between sliding jaws as shown. Prior to the operation the silver spotsare burnished and fluxed. The wires in their guides are then slid into con-tact with the plate. The hot blasts are raised from below so as to aimdirectly at the work. The solder is melted and the attachment completedin about 10 seconds when the bjasts are withdrawn. Slight pressure ismaintained on the wires during this operation by springs in the guides toforce the head of the wire to seat on the spot. A small fillet is obtainedaround the head making the solder cover an area of about 3S to 40 milsdiameter. Crystal units using headed wire attachments have many advantages overthose made with straight or hooked wires. The pull-ofF strength is moreuniform and averages shghtly better than that of hooked wires, despite thefact that only a fraction of the amount of solder used with hooked wires isemployed
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