CHAPTER XVII 
HINGES AND JOINTS 
Chenier joints—Joint tool—Soldering—Brooch joints. 

The hinge to the lid of a metal box is composed of a number of short lengths of tube, or " chenier," soldered alternately to the box and the lid. A piece of wire, called the " joint pin," running through them all, keeps box and lid together. The strips of metal, or " bearers," soldered on both box and lid, when the metal of which they are composed is not strong enough to bear the strain of the hinge, have the effect of strengthening the joint. If they are put on the outside of the box they sometimes form also a convenient stop, by means of which the lid is kept from opening too far. 

To make chenier. Take a strip of the metal which you are to use, measuring three times the width of the tube you wish to make. Carefully remove any burr or rough edge—if left on it would give you trouble later. Make a point an inch long at one end of the strip by cutting little triangular pieces from the two sides. Lay the strip lengthwise over the groove in a swage block, Fig. 20, or even in a semicircular notch cut across a piece of wood. Tap the strip into the groove with a narrow hammer,Fig.21,curlingthe edges upasmuchaspossible— the middle will take care of itself. Then put a drawplate in the vice and draw the strip through a suitable hole. When it has passed through a few holes its edges will meet, and the strip has become a tube. To make sure that the tube is true inside take a piece of copper wire of suitable size, oil it and put it inside the tube. Draw the tube down hard on to it. It is only necessary now to reverse the drawplate and put the end of the wire through a hole which will only just admit its passage, and the wire may be drawn out of the tube. If the chenier is not quite straight it should be annealed, and a number of little nicks made with a needle file along the side upon which the seam comes;—for this crack shows very little, and it is important later on that there be no doubt as to which side of the tube it comes on. Roll the chenier on a flat stake till it is quite straight. See also Chapter VI. page 46. 

You must decide whether you will have the hinge pro jecting from the back of the box, flush with it or sunk a little way below the surface. In the two latter cases the bearers are soldered inside the box and lid; in the former they are outside. Fit and solder the bearers accordingly. Next make the groove in which the " joints " or " knuckles," i. e. the pieces of chenier, are to lie. Take a good deal of care to make this run truly across the box. If it is inclined ever so little the lid will not look straight when the box is open. The groove is to be cut partly in the box and partly in the lid, and it must be just large enough to hold the chenier when the lid is in its place on the box. Fig. 244 shows a joint of five knuckles with bearers, A and B, soldered on outside. Fig. 245 is a flush joint, the bearers being soldered inside in this case. The edges C and D meet when the lid is opened to about a right angle, and keep it from going back too far. In Fig. 246 the joints are sunk below the surface. The bearers are inside in this case also. The wide edges E and F form the stop. They are wide because a clear space of at least 90° from the centre of the pin is always necessary to allow the lid to open as far as a right angle to its position when shut. The joint for the back of a watch is of this sunken type. You will notice the wide bevel near the centre. Fig. 247 shows a hinge which would open beyond the right angle. It would go right back, as it has no stopping edges. The groove may be cut with a file, followed by a round scorper, and finally trued up with a joint file, This is a flat file roughened only on its edges, and these are rounded. Try the chenier in the groove from time to time. When it fits decide as to how many pieces the joint is to be made in. An odd number is always chosen; and the box always has one more piece than the lid. If the joint is of three pieces only, it is well to make the one for the lid rather longer than either of the others, that it may be as strong as the two opposed to it. If the joint is of five or more pieces, they are made of equal length. Cut each knuclde just a shade longer than it will be required, using a piercing-saw. The ends of each piece must now be filed quite truly at right angles to its length; otherwise there would be uneven gaps between the different pieces, and the lid of the box would not open smoothly. 

To true up the ends of the joints you must use the joint tool, Fig. 252. It is a flat piece of hardened steel, perhaps 1 inch square and J inch thick, with a small handle. A triangular or kite-shaped hole is pierced through the middle of the blade. The sides of this hole are filed accurately at right angles to the flat surfaces of the tool. The end of the piece of chenier is put through the triangular hole, and clamped in position with a small set screw provided for that purpose. The extremity of the tube is allowed to project just a shade above the surface. This small amount of metal is now removed with a fine file. You continue filing till the file slides across the surface of the joint tool without being able to remove any more metal from the chenier. The extremity of this is now quite truly at right angles to its axis. Level up the extremities of all the joints in the same way. Take off the burr left by the filing. Bevel off also the sharp corner at the ends of the tube near the crack. Do this to the extent of about a third of the distance round the end of the tube. Now lay all the knuckles in the groove prepared for them, and see that box and lid come together fairly all round. Put a little mark opposite the end of each of the joints, Remove the lid, leaving all the chenier in the groove on the box, Fasten with a clip, or a wire round the box, the alternate pieces which are to be soldered to the box. Remember that tho two end pieces always belong to the box, never to the lid. Take particular care that the crack or seam, left up the side of the chenier when you made it, is in each case turned down into the groove, where it will be soldered safely. If you do not attend to this the joint will be liable to open out later on. You can always find the seam if put the file-nicks in, as suggested above. If you lay the joints which belong to the lid between the others you will be able to see that they are all in their right places. 

Now very carefully put borax to each of the pieces which belong to the box. Takecarethat the boraxdoes not spread, or boil up later, to quite the ends of the pieces of chenier. It might catch the lid chenier, and where it goes the solder will go also. Apply the solder, and fire it just enough to tack the knuckles in their places. Remove the knuckles which belong to the lid, and solder all the others quite soundly. You will now see why the corner of the chenier was bevelled off, as above suggested. The solder has crept round the end of the chenier where it lies in the groove and has filled up the little gap which you. made when you bevelled off the corner near the crack in the tube. If you had not done so there would not now be room for the lid knuckles to go home. For they filled the whole available space before, leaving no room for the solder to trespass on their ground, as it were. Of course you would not bevel the corner of the chenier all round, for the knuckles would not seem to touch in that case. You bevel the tube only at the part which fits in the groove. Some workers stop the solder from running too far by painting the work there with rouge, loam, tripoli or whiting. Always put just the correct amount of solder to fill the joint: not too much nor too little. When the soldering is completed, boil out the box in pickle. See that none of the knuckles have shifted. Then fix and solder the lid knuckles in the same way; and boil that out. Then carefully put box and lid together and run a wire through all the joints. See that everything goes truly. You may like to smooth out the inside of the joint with a broach. Smooth up the chenier both inside and outside the box. Finally take a brass wire which fits, wax it, and push it home. If the box is a silver one it is usual to plug the extremities of the joint with pieces of silver wire, the brass wire being cut correspondingly short. In a good joint the lid should gently close itself when tilted. It should not stick or drop. To make sure that all the knuckles are in a direct line with each other, it is a good plan to run an oiled steel wire through them all, and to leave it in while the soldering is proceeding. You will find this steel wire a great help when wiring the knuckles in their places. 

For a lightly made box the bearer is often made from a section of the tube called the port-chenier or the counter­chenier. You proceed as follows. Draw down a piece of tube till it will fit tightly round the chenier from which the knuckles are to be cut. Force the chenier inside and anneal both together. They will then fit each other exactly. See that they are quite straight. Roll them on a piece of plate glass to ensure this. Then withdraw the chenier. Split the other tube in half, lengthwise, with the piercing-saw and file the edges of each piece true. Cut the joints from the other chenier, true them all in the joint tool and bevel their corners near the crack. Lay them in place within the two halves of the split tube, taking care that the cracks in the knuckles in each case are turned against the split tube, where they will be safely soldered. You may now tie all together with binding wire and solder each alternate knuckle to its own piece of the split tube. In applying the borax take great care to prevent its spreading from one knuckle to another, for it would take the solder along also when the work was heated. Fire the work till each knuckle is just tacked in place by the solder, then separate the two halves of the joint and thoroughly solder all the knuckjes, Bojl out before you try to put the two halves together again. When the joint is complete you may solder each half in place on the box. 

A brooch joint can be made in a number of different ways. We will take the chenier joint first. As a rule, several of these are made together. Take a piece of metal, size 6 on the metal gauge, and make from it a tube which you draw down till it is about T\ inch in diameter. With a fine saw make a number of cuts beginning on the side where the crack is and extending two-thirds the way through the tube. The cuts to be -j\ inch apart. You have now a number of tiny lengths of tube all attached to one another at one side. With the saw cut away as much as possible of the second, fifth, eighth, eleventh, fourteenth and so on, but do not weaken the strip so much that it breaks apart. Your tube now consists of a short length of tube, a gap, two short lengths, another gap, two short lengths, a third gap and so on, all connected on one side, Fig. 248. Next take a strip of metal size 6, as long as the tube, and J inch wide. Tie the tube on to this with its cut side against the strip. Solder the two together, taking care that every one of the pieces of tube remaining is soldered safely. After boiling out, cut away with the saw all the pieces which join the lengths of tube together, Fig. 249. You would have had a good deal of filing to do if you had soldered the whole length of tube to the strip, instead of making the saw cuts and removing every third length, or rather as much of it as was possible. Cut another strip of metal § inch wide size 6, and tie it against the tube at right angles to the other strip. It is to form the bearer or spring, against which the pin of the brooch presses. After soldering it in posi tion, Fig. 250, you can cut your long strip into lengths— two pieces of tube with a gap between. This short length represents the part of the hinge which is fastened to the brooch itself. The pin part has yet to be made. In some joints which can be bought ready made, the tube and the bearer are made from the same piece of metal. They are, therefore very strong. 

To make the pin, take a short length of the same tube which you used for the other part of the joint. Lay it flat on the charcoal with the crack or seam side uppermost. Across it, at intervals of § inch, lay lengths of the wire which you are to use for the pins. Allow | inch of the wire to project over the tube, Fig. 251. Solder each of the wires to the tube, making sure that the crack or seam down the tube is safely joined in the process. With a fine saw, cut through the tube between each pin. The soldering will have made the pins soft, so seize both ends of each pin in turn with pliers and twist it until it is quite hard. Then cut off the -|-inch projecting wire. Very little filing will be required to allow the tube to drop into the gap in the other part of the hinge. The pin or pivot of the hinge can now be slipped in, and its end expanded with a few taps from a hammer. Sometimes the bearer is soldered to the pin instead of to the other part of the hinge. And sometimes a flat strengthening piece is soldered to the pin to protect it from the pressure of the bearer. 

A hinge which will take less room than the joint above described is known as the ball joint. To make it, take a strip of metals,size 10, a full Ainch wide. Grip £inch of the end of it in the pliers and fold it back on to the strip as much aspossible, Fig. 253. Slip another piece of metal of thesame thickness between the two parts, and tap flat, Fig. 254. Cut off the U-shaped piece from the strip and bevel off with a file a little of the inner top edges (marked G) of the U, Fig. 255. The U-shaped piece is to be soldered upside down on to a little metal plate, or even directly on to the back of the brooch. The rounded part of the U is now cut off, Fig. 256, and you have two parallel plates of metal standing up. Now take the pin and solder a tongue of metal i inch deep, and T\ inch long lengthwise underneath one end of it. Harden the pin by twisting or hammering it. File the tongue to the shape shown in Fig. 257. Then push it between the two vertical sides of the U, and drill through all three pieces together. If yon had not bevelled off the inner edges of the U first, the solder employed in fixing it in position would have rounded off the inside corner against the backplate, so the tongue would not have gone home as it should. The projecting corner of the tongue presses against the blackplate and forms the spring of the hinge. With the file round over the top and sides of what remains of the U, then rivet the pin in. In another kind of ball joint the U-plate is made just as above de scribed, but the curved part of the U is not cut away. It is allowed to remain, and acts as the bearer against which the pin springs. The U-plate is soldered so that the corner H, Fig. 256, is turned round to the position marked J. The tongue or blade of the pin, of course, has no need of the projecting corner shown in Fig. 257,as the pin springs against the rounded part of the U-plate. 

A very safe joint can be made from rings of square wire soldered into position. The join in the rings should in each case be against the backplate. The bearer is added as above described. 

The catch of a brooch is generally made from a ring of half-round wire soldered to a backplate. The opening in the ring being in this case at the side, and not against the back plate. In some cases no backplate is used, the catch being made from flattened wire curled up as required and soldered to the back of the brooch.