When a cast breaker part failed, we machined a stronger one.

The challenge

The part shown is from the operating mechanism of a Siemens SF6 circuit breaker. The original is an OEM aluminum casting, and during operation it failed catastrophically, fracturing clean through the splined hub. When a cast mechanism part lets go like this, the breaker is out of service, and a like-for-like replacement often isn’t sitting on anyone’s shelf.

Our approach

With the OEM casting in pieces, we reverse-engineered the component directly from the failed part, capturing the spline, bore, and lever geometry, and machined a replacement from solid billet stock instead of casting it. A machined billet part is more homogeneous than a casting, without the porosity and weak grain boundaries that can drive this kind of fracture, so the replacement is not prone to the porosity and weak grain boundaries that drove the original fracture.

The result, a full turnkey repair

Because Southern Switch & Contacts runs both a machine shop and a substation field crew, we didn’t just ship a part. Our team installed the new component on-site and returned the breaker to service, one vendor, one point of accountability, from the broken casting to power back on. That is the difference between ordering from a parts catalog and working with a machine shop that can make what failed and put it back in service.