Electric Soldering Iron: Miner, 1890

Earlier electric soldering irons heated a hollow copper head from inside, through finely divided carbon pressed against the tip, so the whole outside of the head lost heat to the air. Willard M. Miner of Plainfield, New Jersey, patented the alternative in 1890, US 421,185: keep the copper head solid, which holds its heat longer, and wind the heating resistance round the outside of it, under a shell that concentrates the heat on the copper and stops it escaping. The coil is German silver wire, wound round a reduced part of the head without touching it, with one end connected to the head and the other to the supply.

中级

Workshop process

说明

Turn the head

Turn a solid copper head with its point. A little back from the point, cut the head down to a smaller diameter for some distance, leaving a shoulder, and thread a shank at its rear end.

此步骤所需材料：

铜圆棒1 个

所需工具：

金属车床

Wind the coil

Coil German silver wire round the reduced part of the head, the coil slightly larger than the head so the two do not touch. Connect one end of the coil to the head at the shoulder; the other end goes to the supply.

此步骤所需材料：

德银电阻丝1 as required

所需工具：

钢丝钳

Shell

Slip on the shell, of brass lined with non-conducting material. Close its inner end with an insulating disc held by a washer and nut on the threaded shank.

此步骤所需材料：