Part number 4471-B is a cast iron gearbox housing for a paper machine drive. We machined the first batch of twelve in 2011. This spring the last of them came back for the third time, and this time we could not save it. Here is what happened to one casting over fifteen years.
First life, 2011
Cast at a foundry in Belgium, machined here in two setups. Bore diameters to H7, faces flat to 0.02 mm. Dimensional report in the box. The housing went into a drive that runs three shifts.
Second life, 2017
The bearing seats had fretted. The customer’s first instinct was to order new. We asked to see the part first. Stripped, cleaned and measured against the 2011 drawing, the casting itself was sound; only the seats were worn. We bored them oversize, fitted sleeves and machined the sleeves back to the original H7. Same drawing, same tolerance, same report. Forty per cent of the cost of new.
Second life again, 2022
Same story, five years later. Sleeves out, new sleeves in, re-machined. By now the housing had run eleven years and been re-certified twice.
A part is not worn out when it is worn. It is worn out when there is no material left to bring it back.
Third life, 2026
This spring the housing came back with a crack through the mounting foot. A crack in cast iron is the end. The housing was weighed, sorted into the grey-iron stream and returned to the mill with its certificate of origin. Eighty-four kilograms of iron, back into the melt. The customer ordered a new one from the same drawing, and the tooling was still on the shelf.
