General

This chapter presents methods for joining the various pieces of Do-It-Yourself Aluminum to each other and to other materials. It shows many types of joints and how to make them. These joint details are collected in this chapter to avoid repeating them again and again where the same joint appears in several different items.

For projects exposed to the weather continuously, such as awnings and lawn furniture, always use aluminum fasteners to avoid dissimilar metal corrosion. If it is necessary to use other metals for certain parts such as bolts, hinges, or reinforcing angles, be sure to coat them with aluminum paint or clear lacquer before assembly. Paint or enamel is also suitable.

Joints in window-screen sections and storm-window sections are detailed in free instruction sheets available at all hardware stores handling Do-It-Yourself Aluminum, so directions are not repeated here.

Riveting is widely used because it offers a permanently tight fastening that is easy to make, inconspicuous, and reliable. To avoid movement sidewise between members joined, drill rivet holes just big enough to insert the rivet. Where several rivets are used in a single joint, drill hole for one rivet only; insert and head up that first rivet; then drill the next hole and head up that rivet; and so on. This assures correct hole alignment.

Use vise or C-clamps to hold members exactly in position desired. Then drill through both members to be joined. Avoid attempting to drill matching holes before assembly. After drilling, clean off any metal upset or turned up around the edge of hole.

Every rivet comes with a head already on one end .... the "formed" head. You must make the head on the other end .... called the "driven" head. Insert the rivet, and position the work with the formed head against a heavy solid object such as a vise or metal block. Obtain a block of iron or steel for this purpose from your local scrap yard or any welding shop . . . . 1" x 2" x 4" is a convenient size. Hold this backup block against the formed head while you upset the driven head. For easy access, put the formed head inside when working on box sections.

Obtain the correct amount of metal to make the driven head by cutting off rivet shank so that it extends through the work a distance 11/4 to 11/2 times the rivet diameter.

Be sure parts to he joined are clamped together tightly before upsetting the rivet.

Start to form the driven head by strik-ing on the end of the rivet several blows directly in line with the rivet shank. This upsets the rivet shank to make it fill the rivet hole completely. Use flat face of hammer for this operation.

Now use the ball-peen face of the hammer to strike blows directly in line with the rivet shank but around the edge to form the metal down and around the work. Make the driven head look like the formed head.

Invisible Riveting of sheet to bar or angle is accomplished by countersinking the heavy member on the surface next to the sheet, which is then forced down into the depression so formed. The driven rivethead then fills this depression, giving a smooth level surface on top. See Fig. 4-1 for details.

In another method (Fig. 4-2) used with leather-embossed sheet, cut the rivet shank off close to the sheet and work edges of rivet over hole in sheet with a small ball-peen hammer. Touch up with steel wool. Done carefully, the pattern on the end of rivet will blend with the embossed sheet pattern.

Removing Rivets

A misplaced or badly driven rivet is removed easily by center-drilling through the head of the rivet with same sized drill used for the original rivet hole. To locate the hole accurately, file a flat on the top of rivethead and carefully center-punch exact center to start drill properly.

Self-Tapping Screws

To join sheet to sheet with self-tapping screws, drill top sheet with hole large enough to clear screw. Punch hole in lower sheet, as this will provide double the holding power as compared with drilling. Figure 4-3 indicates punching with a nail. An ice pick is also excellent. Use a wood block for backup to avoid deforming sheet.

To fasten sheet to a plaster wall, first drill all the holes in the sheet large enough to pass a #8 x self-tapping screw .... the size recommended. Then position sheet on wall, and drill into plaster through the center of two of these guide holes, going clear through the plaster with a #32-size wire drill.

Then insert screws in these two holes, being careful to hold them steady and guide them straight into the hole. Exert a steady pressure while screwing into hole. Do not set up screw too tightly, or it will break plaster. If drilled and the screw driven properly, plaster will not break out and the screw will provide excellent holding power.

With first two screws in place, drilling and driving the remainder are easier, as the sheet is now held securely in position.

Slots and Tabs (Fig. 4-4) are handy for joining many sheet parts. Cut slot with 1/4" chisel as shown. Use shears and chisel for cutting tabs as directed in Fig. 2-5. After inserting tabs, lock joint by bending them over in opposite directions, wherever possible.

Sheet Edges

To join two sheets, turn up a flange and fold it part way down along the edge of both sheets. Interlock the two folds and hammer flat with a wood block (Fig. 4-5). In this joint, one sheet is at a higher level than the other at the joined edge.

To keep the sheets at the same level, turn both folds up and use a slide clip to join them as in Fig. 4-6. Lock either joint by dimpling or riveting or with sheet-metal screws.

Corners Of Box Sections

Many projects employ box sections where the bottom of the box, the two ends, and the two sides are cut from a single piece of sheet. After flanging up the sides and ends, locking the corners completes the box section.

The most widely used corner connection (Fig. 4-7) employs bolts or rivets to hold a flange on one member to the adjacent member. A corner lock that uses neither rivets nor bolts is the double-bend lock shown in Fig. 4-9. Make this connection in two stages as shown.

A third method (Fig. 4-8) employs a simple corner clip locked to the members to be joined on the inside of the corner by means of folds as shown. Make this assembly first with folds only partly closed; then hammer them tight, using a wood block to prevent marring the metal. Dimple with punch.

To make the clip, cut a piece of sheet 11/2" wide and as long as height of the corner of box. Bend in middle with form block, and then bend back 3/8" from each edge.

Continuous Hinge

Make two sets of interlocking tabs by first marking out one set on the edge of one member. Make tabs 3/8" long, 1" wide, 11/8" between tabs. Cut with shears and chisel as in Fig. 2-5. Use this set of tabs to mark outline of matching set of tabs on the other member. Cutting just inside this outline provides proper clearance between the two sets of tabs in the hinge.

Now flange up both sets of tabs 90°, and interlock them with a piece of wire coat hanger or aluminum clothesline wire between them as in Fig. 4-10. Turn down tabs over wire with screwdriver as shown. Complete the forming with pliers (Fig. 4-11) to make the finished hinge.

Tips For 3/8" Rod

Rubber crutch or cane tips of 3/8" inside diameter make excellent tips for end tables and other projects using rod for legs. Obtain them at your local hardware or variety store. To modernize the shape, slip the tip over a short length of 3/8" rod and rotate the rubber tip against a sanding disk to cut off extra rubber, leaving a smooth cone-shaped tip. Shorten the tip in the same manner where desired.

Small tack-type hard-rubber glides or bumpers also provide fine tips for use on 3/8" aluminum rod. Drill 1/8" diameter hole 1/2" deep in end of rod. Drive in a hardwood plug. Then drive tack-type bumper or glide into the wood.