ROAD AND WORKSHOP by Handyman
Page 41
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Arc Welding Hints—Fillet Welding, Downhand
VILLET welding refers to the joining 1 of plates at angles to each other, where the edge of one plate rests on the aat of another. On light work, a single fillet is run along the inside of the angle --for a stronger job, a T-fillet weld provides a run along both sides. This work may be tackled in two ways, either on the bench with one plate vertical, or positioned in V formation. On the vehicle, Of course, the welder may be faced with positional runs, which could be downhand, vertical or overhead. The task at the moment is to fillet weld a a vertical i-in. plate to a On. horizontal 3ne.„
The first job after cleaning is to position the plates, and tack them together. If the run is a short one, end tacking
will do, but if more than I ft., +-in. tacking runs should be made. When set up on the bench, this task may look a simple one, yet for the beginner it can be anything but simple, and he will need considerable practice to place the deposit equally on both plates. If he is not watchful he will tend to pile the deposit against the vertical plate without obtaining good penetration.
The important factors are the electrode angle, which should be 40'; also a short and really crackling arc to bite right into the root of the angle (see Fig. I, which shows a single fillet weld and Fig. 2 which is the T-fillet weld). If the vertical plate in Fig. 2 is to be welded at the edge of thc bottom plate, as in chassis repair, a single bevel is advised along the outer edge of the vertical plate. The centre fine of the electrode should be aimed at the join' line which will now, appear slightly inboard of the edge, and which will then give equal penetration of both plates. Again, a short arc is most important.
In certain instances of fillet welding, it is pOssible to position the work and this is done in V form—the method now used is the same as the V butt weld. Again, care must be taken to obtain sound root penetration and so avoid .slag intrusion. Where there is poor root penetration slag will collect, and can cause .premature failure. In fig. 3 it will be seen that root penetration is good and the joint sound. In Fig. 4, however, the fillet merely bridges the gap with no penetration. This joint will fail under load.