01 Free tool
Read any weld symbol on a print.
Nine symbols and one reference line. Learn these and you stop guessing on a drawing for the rest of your career. Use the reference below.
Fillet
Right triangle
The most common symbol in the trade. The perpendicular leg is always drawn on the left.
Square groove
Two short parallel lines
Thin material butted together, square edges, little or no preparation.
V groove
V
Both members bevelled. The standard preparation on thicker plate and pipe.
Bevel groove
Half V, one leg vertical
One member prepared, the other left square. The vertical leg points at the prepared member.
U groove
U
Thick material. Takes less filler than a V for the same thickness.
J groove
J
One member with a J preparation, the other square.
Plug or slot
Rectangle
Filling a hole or an elongated slot in one member to fuse it to the member underneath.
Back or backing
Semicircle
A weld on the reverse of the root. Back goes on after the main weld, backing before it.
Surfacing
Wavy line
Building a surface up rather than joining anything. Hardfacing and buildup.
Shapes per AWS A2.4. The two that get mixed up most are plug or slot, which is the rectangle, and back or backing, which is the semicircle. Below the line means the side the arrow points at. Above the line means the far side. The number on the left is the size, the numbers on the right are length and pitch, so 3-6 is three inches of weld every six.
Symbols are the easy part.
Which ticket opens which door, what the work pays and how to not waste three years in the wrong shop. That is the rest of the book.
