Tin, sheet iron and copper plate worker

The present is a new and thoroughly revised edition of one of the most popular books on sheet-metal working ever published in this country. It having been found necessary to make a new set of electrotype plates and new engravings the old ones having been worn out by actual use it was determined to have the book re-edited and to add to it, in the different departments, new, recent and necessary matter.

In as much as geometrical problems never become obsolete and as pattern cutting is based on that science, the original problems are as correct and useful as ever and have therefore been retained. These have been augmented by the supplementary problems which have been incorporated to emphasize the modern system of triangulation and to give some knowledge of modern skylight work. As a result, that department of the book, valuable heretofore, is now considerably improved.

The portion treating on metallic alloys and solders has been entirely rewritten, so as to have a more systematic arrangement and to bring it abreast with the best modern practice in this interesting and important field. Experts have carefully gone over the recipes and tables to insure their accuracy.

In all the other departments new matter has been added and every effort has been made to render the entire work, in the future, if possible, even more useful to the tin, sheet-iron and copper-plate worker than in the past.

Reference to the many subjects treated will be rendered easy by the very full table of contents and the complete index.

The following are the more important seams or joints used in metal plate work.

Fig. 170 shows the various methods of making joints at angles of sheet-metal. A and B are .or the thinnest metals, such as tin, which require a film of soft solder on one or the other side. Sheet lead is similarly joined, and both are usually soldered from within.

C and D are the butt and mitre joints used for thicker metals with hard solders. Sometimes D is dovetailed together, the edges being filed to correspond coarsely; sometimes they are partly riveted before being soldered from within. These joints are very weak when united with soft solder.

E is the lap joint, the metal being creased over the hatchet-stake. Tin plate requires an external layer of solder; spelter solder runs through the crack and does not project.

F is folded by means of the hatchet-stake; the two are then hammered together, but require a film of solder to prevent their sliding asunder.

G is the folded angle joint used for fire-proof deed boxes and other strong work in which solder would be inadmissible. It is common in tin and copper work, but less so in iron and zinc, which do not bend so readily.

H is a riveted joint, which is very commonly used in strong iron plate and copper work, as in boilers, etc. Generally a rivet is inserted at each end, then the other holes are punched through the two thicknesses. The head of the rivet is put within, the metal is flattened around it, by placing the small hole of a riveting set over the pin of the rivet, and giving a blow ; the rivet is then clinched, and is finished to circular form by the concave hollow in the riveting set.

In IK one plate is punched with a long mortise, the other being formed into tenons, which are inserted and riveted. K, however, has tenons with transverse keys, which can be taken out and the plate released.

Fig. 170 also illustrates straight joints. L is the lap joint employed with solder for tin-plates, sheet-lead, etc., and for tubes bent of these materials.

M is the butt joint used for plates and small tubes of the various metals. When united by hard solder or brazed, such joints are moderately strong, but with soft solder they are very weak from the limited superficies of the adhering surface.

N is the cramp joint. The edges are thinned by the hammer, the one is left plain, while the other is notched obliquely with shears for one-eighth of an inch deep, each alternate cramp is bent up, the other down, for insertion of the plain edge. They are then hammered together and brazed, after which they may be made nearly flat by the hammer, and quite so by the file. The cramp joint is used for thin work requiring strength. Sometimes the lap joint (Z) is feather- edged. This improves it, but it is still inferior to the cramp joint in strength.

O is the lap joint, without solder for tin, copper, iron, etc. It is set down flat with a seam set, and is used for smoke-pipes, and numerous "works not required to be steam and water tight.

P is used for zinc works and others. It saves the double bend of the preceding. It is sometimes called the "patent strip over lap."

Q is the roll joint, used for lead roofs.

R is a hollow crease, used till recently for vessels and chambers for making sulphuric acid. The metal is scraped perfectly clean, filled with lead heated nearly to redness, and the whole united by burning with an iron also heated to redness. Solder which contains tin would be attacked by the acid. This method of soldering is now superseded by autogenous soldering.

ST are joints united by screw bolts or rivets, for iron and copper boilers, etc.

U, united with rivets in ordinary manner of uniting the plates of marine boilers, and other work requiring to be flush externally.

V is a similar case, used of late years for constructing the largest iron steam-ships, etc. The ribs of the vessel are made of T iron, varying from about 4 to 8 inches wide, which is bent to the curves by the employment of very large surface plates cast full of holes, upon which the wood-model of the rib is laid down, and a chalk mark is made around its edge. Dogs or pins are wedged at short intervals in all these holes, which intersect the course. The rib heated to redness in a reverberatory furnace, is wedged fast at one end, and bent around the pins by sets, and sledge-hammers, and as it yields to the curve each pin is secured by wedges until the whole is completed.


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