We have recently completed work on Tornado's superheater header which has been refurbished as part of the locomotive's major overhaul.
This particular job included reconditioning of all 86 superheater element seats and re-threading inspection plug bores and making replacement bronze plugs.
Machining the casting, which has spent more than 10 years in the harsh environment of the locomotive's smokebox, has not been as straightforward as machining a completely new component would be. This is mainly due to localised distortion and oxidation.
The most difficult feature was to re-cut the taper on an inclined axis through the main flange to a more suitable angle of 23.8 degrees. This should result in a perfect fit with the main steam pipe. The task involved using an optical protractor and sine bar to set up the workpiece precisely. We designed and manufactured a special tool to cut the prescribed angle assuring the best achievable finish.
Here are some pictures showing the before and after state of individual machined features as described above.
