This section is from the book "A Practical Treatise On The Joints Made And Used By Builders", by Wyvill J. Christy. Also available from Amazon: Practical treatise on the joints made and used by builders.
This is formed by turning up two adjacent edges of a piece of sheet lead at right angles, pinching the corners together, and then doubling back the pinched-up part against the upstand, as in Fig. 141. It is a joint used for dressing up lead against the end of a gutter, etc, instead of bossing it up, and making it is sometimes denominated pig's lugging instead of dog's earring, but even to a connoisseur in such matters there can be but little choice between the two appellations.
Double Cone Joint is a mode of connecting two lead pipes without solder and very similar to the cone joint already described, being manufactured by the same well-known firm, and intended for situations where skilled labour is difficult to obtain. It is made by opening out both ends to be joined with a tanpin of the same degree of taper as that of the two ends of a loose piece of brass having a corresponding bore to that of the pipes, and which can thus be inserted into their enlarged ends. Previous to their enlargement, however, a gland nut is slipped over each end, so that all that remains to be done to make a sound joint is to draw the nuts together with bolts in a manner exactly similar to that represented in Fig. 138.
Drip Joint is represented in Fig. 142, and is a means adopted for joining sheets of (7 lb.) lead in gutters and flats to allow for contraction and expansion. When the joint is across the current the plumbers' drip occurs about every 9 ft. or so, and consists of a low vertical step in the boarding, from 2 in. to 3 in. deep, having a rebate to receive the lower sheet, which is dressed close down over it. The upper sheet is then turned down over the upstand and dressed to within 1 in. or ¾ in. of the surface, in order that dirt may not collect at the bend and cause damp to rise by capillary attraction. When the joint is in the same direction as the current it can be formed as shown in Fig. 143. The bottle nose variety has been already explained.
This is noticed under Expansion Joint. Elbow Joint is one formed at the end of an elbow which may be either screwed for iron with or without a running nut at one end, whilst the other is tinned for lead or else provided with a union similarly tinned. Or the elbow joint may be of the kind described under Cone Joint. In lead piping elbows were formerly made instead of bends by cutting one pipe and inserting the other at the mitre, resulting in an upstand being left inside the pipe from too much overlap, besides impediments in the shape of pro-truding spurs of solder. Elbow joints are now made by cutting a piece out of the throat of the pipe, pulling it together to the proper bend, and working the lead neatly over the throat so that there may be no obstacle left to the flow, and finally soldering it up with a neat tight joint, which need not extend all round to the heel.