Onsite Grinding of Steam Boiler Manholes
When Mighty River Power’s steam boiler at the Penrose Power Generation plant was leaking due to corrosion on the manhole covers, they called in Otahuhu Engineering’s expertise to grind the faces true.
Due to the space restrictions, the machining could not be done with a conventional flange facer. After exhausting all other possibilities in NZ they contacted Tony Cranch at OEL.
We flew over the only Oval Manway Grinder in Australasia and were on site the next day to grind the six oval manholes. The job was completed within the projected time and this enabled Mighty River Power to achieve a 100% sealing, with minimal disruption to their schedule.
Line Boring of 200 Ton Digger
We were asked to build up and re-machine two swing box holes on a 200-ton Liebherr 994 excavator at the Rotowaro Coal Mine at Huntly. The job was very successful and we were contracted to do their second 994 excavator.
Line Boring 50 Metre Superyacht
When working on a $32 million superyacht it is paramount the quality of work carried out is to the highest standard. Otahuhu Engineering was entrusted to complete the line boring of two stern tubes and rear supports for a 50 metre alloy superyacht. It entailed accurately machining the bores and flange faces (using our purpose built variable feed facing head) to enable the 150mmØ prop shafts, driven by two 3000hp Caterpillar engines, to be accurately supported. Any misalignment could cause vibration of the prop shafts when under load so the set up was critical. Using our alignment gauge to set up the supporting bearings we could ensure the accuracy of the completed job. The machining was completed within the tight time frame of the customer.
Manufacturing 3 Metre Motor Spacers
When we were asked to manufacture two 3 metre square spacers for large motors at the ARC sewerage works we had to put our thinking caps on. The spacers were fabricated, stress relieved, and machined on the faces, in our workshop. It required us to modify our milling head to fit on our 4-metre lathe hence, enabling us to machine the top face and o-ring groove. Being able to complete the job in house enabled us to produce a cost-effective job for our customer.
Racking Access Cranes
We have been involved in two projects for installing racking access cranes. Both consisted of cranes that are 24 metres tall and work in the racking of a storage facility. They both involved setting the machine to very close tolerances – typically ±1mm over 50 metres, and required the installation of over 1km of rails for each project. Both projects were a challenge for us and we are proud of the achievements we made on them.
Restoring 1880 Cannon
We were commissioned by The Department of Conservation and Salmond Reed Architects to help restore and remanufacture two breech blocks, for an 1880 Cannon at North Head in Devonport. This consisted of casting the breech block head from bronze, manufacturing a new galvanised breech block from scratch, restoration work to the barrel, and designing and building a new supporting framework, to enable the gun to be fired for the first time in nearly 100 years. The project was completed on time and within budget.