Autonopedia

A

Before starting these welding lessons, study carefully the description of fire welding in Chapter 4.

Take a NEAR WELDING heat on each bar in turn and upset the ends which are to be welded to ^1/2" thick, but keep the width the same.

B

Before starting a large scarf, the upset end of the bar should be forged to a short bevel, leaving the edge about thick like this -

The hammer blows should be delivered at an angle of 45°.

C

Next, with the bevelled edge downwards over the rounded edge of the anvil, forge the scarf as shown here -

D

Before starting to weld, remove any clinker from the fire which must be clean with a good heart.

Lay both pieces side by side in the fire with the scarf lips on top. To ensure they are both heating equally, jockey them about and, as they approach welding heat, draw each in turn to the edge of the fire to judge the heat.
If sand is being used as a flux now is the time to sprinkle a little on each piece.

E

Now work quickly take both pieces from the fire together, tap them over the edge of the anvil to knock off the dirt, and lay them on the anvil with the scarfs matching and the middles in contact.

The order of the first three blows is important

First on the centre of the top scarf so that any dirt is driven out towards the ends.

Second on the thick part of the top scarf so that it welds to the thin end of the under scarf which is being chilled by the anvil face.

Third on the thin end of the top scarf before this cools.

F

If another heat is necessary to complete the weld, take it now.

Continue welding by turning the piece to and fro, hammering both sides alternately. Take care not to reduce the section below the size of the original bar.

G

The completed weld should be like this, with no reduction of section and with the corners very slightly chamfered.

The finish of the weld should he smooth, as a rough edge or a hammer mark may cause a fracture to start.