There are a number of ways to join the different shapes and sizes of aluminum stock using rivets, clips, tabs and slots, grooved seams, screws and nuts and bolts.
RIVETS – First choose the proper size drill to make the hole for the rivets. The shank of the drill should match the body of the rivet for a good tight fit. The proper length for the rivet to hold properly and firmly should be approximately one and one half times the thickness of the rivet.
Insert the rivet into the drilled holes and make sure that the sheets being joined are drawn together. Back-up the rivet with a piece of steel and with the ball end of your ball pein hammer, mushroom the end of the rivet. Follow this procedure until you have completed joining the sheets. Smooth all rivet ends with a power tool, fine sandpaper or emery cloth.
TABS AND SLOTS – Mechanical interlocking of various pieces in an aluminum project can be accomplished by cutting the tabs and slots carefully with a ¼” wood chisel. If you go through Junior’s toy box you will find a good many of his toys joined in this fashion and you can see how it is done.
GROOVED SEAM – The simplest method of joining two pieces of sheet metal is the grooved seam. To do this, first fold over the corresponding edges an equal amount, hook the lips together then with a mallet and block of wood, hammer them together. A few dimples along the seam made with a hammer and center punch or nail will prevent the seam from working loose.
In working on some of your projects, you may find it necessary to join a bar to a rod with a rivet. Your joint will be simple and strong if you form a shoulder on the rod by sawing or filing a flat surface on the rod then joining the two pieces and drilling a hole for the rivet.
The procedure just mentioned is followed to make a swivel joint on two rods, except that both rods are filed flat and then drilled and riveted.
Angles can be joined to metal sheets with self-tapping screws, sheet metal screws or in some cases nuts and bolts.
There are a number of methods of joining sheet metal to tubes. One is to slit the tube lengthwise, insert the sheet metal into the slot and secure with a sheet metal or self-tapping screw. The sheet metal can also be kept firmly in position by inserting dowel rods into either end of the tubing.
Tubing can be used for a leg or stand by making four flaps in the end of the tube, bending them over and placing screws through the flaps into the piece of wood or metal to be supported.
Comer gussets can be used to join angles or bars with rivets or nuts and bolts. When you bend a piece of angle aluminum to make a corner, the wedge of metal cut from the angle leg can be used as the reinforcing gusset for that corner.
When it is necessary to join two ends of a bar as in trimming counter tops a dovetail joint will hold firmly and neatly. Mark the joint carefully and accurately with a scratch awl, then cut with a saw on the inside of your markings, then carefully file away excess metal for a perfect, tight joint.
A hinge may easily be cut and bent, using a piece of wire coat hanger for the hinge pin. Many intricate designs and antique hinges can be easily made of aluminum for any of your projects. When measuring the tab allowance, mark off 31/2 times the diameter of the wire on each side. Always make an odd number of sections to equalize the strain.
In many cases, for decorative effects, you may wish to join two sections of sheet metal together with a clip. To make this joint, bend back both edges an equal amount, from another piece of metal form a clip by determining the amount of bend necessary to draw the two sheets firmly together. Force the clip onto the bent sheet edges with a mallet, level and tighten the clip by.malleting over with a smooth block of wood and dimple with a nail or center punch for added strength.
A favorite woodworker’s joint, the cross-lap, can also be utilized with Do-It-Yourself aluminum bars and rods. Here again as with the dovetail joint extreme care is necessary for an accurate joint. Mark the pieces with a scratch awl, saw inside the awl marks and finish with a file, checking frequently for a proper fit.
Aluminum tubes can be joined to many flat surfaces such as wood, angle metal, sheet metal, bars and other material by squeezing the end of the tube flat in a vise and drilling for screw holes. Tubes can be joined to wood for legs by using the above method or by inserting a section of wood dowel in the end of the tube and running a screw through the tube, dowel and into the wood. Tubes can be lengthened by inserting a plug part way into one end of the tube and forcing another section of tubing over the wood plug. Screws can be driven into the tube section to give added strength.
A “T” joint or other butt joint can be made with aluminum tubing if the tube end is fitted with a dowel. This tube end is then marked and cut with a scroll saw and a half- round file to the outside dimensions of the tube it will be joined to. A long wood screw is then driven through the tubes for a long-lasting tight joint. A variety of joints and fastenings can be devised for the Do-It-Yourself Aluminum. You will find that as you begin to work with this metal you will develop special joints and fastenings to suit the particular projects you are working on. There are also special elbows, T-butt and flanges available, made of aluminum, to fit all sizes of tubes.