Cutting and Sawing

After having traced or otherwise marked out the design or shape you want on the sheet of metal with the sharp point of your center punch or an awl, or scribed it with your dividers you can cut it out with your snips if the sheet is thin enough. If it is too thick to be sheared then saw it out with your jeweler's or hack saw.

Should you want to make a hole or an open design of any kind in thin sheet metal you can easily punch it in with your center punch, or cut it out with a stencil cutter's chisel, which is simply a very sharp cold chisel.21 But should the metal be too thick to punch or cut in this way drill a small hole in it and you can then saw out the part with a jeweler's saw frame and blade just as you would saw out a piece of wood with a scroll saw, though you may have to hold the metal in a vise.

Making Seams and Joints

The next thing to do after having cut out the different pieces of metal is to put them together. The way you do this will again depend very largely on the thickness of the metals, but in any event where the pieces meet, a seam or a joint must be made.

20 How to make working drawings is explained in Chapter V. Fuller directions will be found in Inventing for Boys, by the present author, published by Frederick A. Stokes Company, N. Y.

21 See Chapter VIII.

If the metal is thin the pieces can be lapped and then soldered or riveted together as shown at A in Fig. 29

A- Lap Seam

B - Grooved Seam

C - Lap Seam Riveted

D - Butt Joint Bolted

E- Box Lap-Joint

F - Box Grooved Seam

G - Butt & Pieced Joint

H - Corner Butt Jolnt Screwed

I - Circular Lap Seam

J - Circular Folded Seam

K - Circular Overfold Seam

Fig. 29. how metal seams and joints are made or you can make a folded seam as shown at B. If, however, the metal is thick you can make a lap seam and either rivet or bolt it together with screws having nuts on them as shown at C.

A strong butt scam can be made by hard soldering or brazing the edges together but it takes a hot flame and considerable skill to do a good job of this kind. Another way to make a butt seam of two thick sheets of metal is to lay them with their edges together and then rivet a strip or plate on both sides of them as shown at D.

In making corner joints one or both edges of the sheet should be bent over as pictured at E when they can be soldered, riveted or bolted together; or a grooved seam can be made as shown at F if the metal is thin enough.

If the pieces of metal are say 1/16 inch or more thick you can put a three cornered piece of metal in the corner and drill and thread it so that the pieces which form the butt joint can be screwed to it as shown at G, or if one of the pieces is thick enough you can drill and thread it and screw the other piece to it as shown at H.

When putting ends on tubes and cylinders you can make a circular lap seam as shown at I, or a circular folded seam as at J or a circular overfolded seam as shown at K.