It Failed Again.
A component that fails repeatedly in the same way is showing a design or material problem, and a machined replacement can be changed to address it rather than reproducing the original weakness.
- Situation /
- Planned work
- Steps /
- 5 to get moving
- Bring /
- 4 things
- Call /
- 337-837-2314
A component that fails repeatedly in the same way is showing a design or material problem, and a machined replacement can be changed to address it rather than reproducing the original weakness.
You have replaced this part before. Maybe more than once. It fails in roughly the same place, in roughly the same time. Buying another identical one buys another identical failure.
What to do
- 01
Keep the failed parts and look at where they broke
Fatigue failures start at a stress concentration and leave a distinctive surface — smooth beach marks spreading from an origin, then a rough final tear. Where the origin is tells you what to change.
- 02
Check the fillets first
On a rotating shaft, the radius at a shoulder is very often the deciding feature. A sharp corner concentrates stress and is where cracks start. Increasing that radius is frequently the single highest-value change available.
- 03
Then question the material
Not always a strength problem. A part failing by wear needs surface hardness; one failing by corrosion needs a different alloy; one failing by shock needs toughness rather than hardness. These pull in different directions.
- 04
Consider the surface finish where it matters
Tool marks in a highly stressed fillet act as crack starters. A better finish in that one small area is cheap and can change fatigue life substantially.
- 05
Change one thing at a time
If material, geometry and finish all change at once and the part survives, you have learned nothing about which change mattered — and nothing about what to do when the next one fails.
Questions People Ask
Why does the same part keep breaking?
- Repeated failure in the same location almost always indicates a stress concentration, a material mismatch, or a fault elsewhere in the machine overloading the part. Fatigue failures leave a characteristic surface that points to where the crack started, which is where the fix belongs.
Can a replacement part be made stronger than the original?
- Usually yes. A machined replacement is not bound by the original production method, so material, hardness, fillet radii and surface finish can all be improved. The improvement has to target the actual failure mode — simply making it harder can make a shock-loaded part fail sooner.
Send us the part.
337-837-2314 — or send photographs and we will tell you what we can do.