Short answer
A breaker tool is not welded. The reason is neither cost nor warranty but the material itself: the tool is alloy steel heat treated to give a particular balance of hardness and toughness. Welding heat destroys that balance where it touches; a hard, brittle band forms around the weld. That band does not flex under impact, it cracks. A tool extended or built up by welding does not last longer, it breaks sooner and more dangerously.
Why the tool material is special
A breaker tool takes tens of blows per second. To carry that load it has to hold two opposing properties at once: hard enough to resist wear, tough enough not to fracture. That balance comes not from the chemistry of the steel but from its heat treatment; the same steel with a different treatment is either glass brittle or soft.
Welding applies very high temperature locally and then leaves it to cool fast. That is an unintended quench: the area hardens but loses its toughness. It cannot be seen, it cannot be measured with a caliper, and it shows up only at the first serious blow.
Three site remedies and why they fail
- Extending a shortened tool by welding: the weld sits at the most highly stressed point of the tool. The tool breaks there and the broken piece flies out onto the site.
- Hardfacing a worn tool: the deposit is hard but the zone beneath it has been embrittled. The deposit holds for a while, then lifts together with the crack underneath it.
- Welding a mushroomed head back into shape: mushrooming is removed by grinding, not by welding. Welding leaves the cause of the mushrooming untouched and adds a brittle zone on top.
The only legitimate intervention is grinding
The only operation allowed on a tool is grinding away a mushroomed or burred edge, and even that has a limit. Grinding must be done in short passes without letting the area glow, with water or air cooling; an area that changes colour has already lost its heat treatment. We set out the method and the limit in the mushrooming guide.
The safety side
This is not only an economic matter but a safety one. A breaker tool works under impact and when it fractures the pieces separate at high speed. A fragment breaking from an embrittled zone carries enough energy to reach a cab window or a person standing nearby.
For that reason "let us try it and see" is not a sound approach to a welded tool. The cost of the trial is not the price of the tool but what happens at the moment it breaks.
Do and don’t
Do
- Replace a worn tool; the tool is a consumable you can plan for.
- Grind mushrooming early and with cooling rather than waiting for it to grow.
- Investigate why the tool finished quickly: angle, blank firing, lubrication, tool type.
- Set aside a tool that has reached its length limit so it cannot be refitted by mistake.
- Choose the tool type to suit the site; the right type already lasts longer.
Don't
- Do not weld, extend or hardface the tool or its shank.
- Do not let the area glow while grinding; a colour change means the heat treatment has gone.
- Do not try to weld the pieces of a fractured tool back together.
- Do not use the tool as a lever or pry bar; a bent tool cannot be repaired anyway.
- Do not fit a welded tool "just to see".
So why is the tool finishing early?
- Wrong tool type: a chisel in abrasive hard rock or a moil in soft material shortens the life.
- Wrong angle and prying: side load damages both the tool and the bushing.
- Blank firing: blows continuing after the material has broken load the energy back into the tool itself.
- Long insistence on one spot: a heated tool softens and mushrooming starts there.
- The lubrication routine: a shank running dry and dusty wears both itself and the bushing.