Proof machining of the Coupled Driving Wheels
With the completion of the casting, the six coupled wheels were transferred to ADA Machining Ltd (Ashton under Lyne) for proof machining towards the end of June, this being the preferred company for that task by William Cook Cast Products (WCCP). ADA were initially visited by the Trust to explain the scope of work, agree an outline programme and review the working methods, facilities and personnel to be involved. Proof machining involves the removal of material to achieve near final dimensions, demonstrating integrity in the casting and prepare each one for subsequent Non Destructive Testing by WCCP at their Sheffield Works.
Another visit to ADA in mid July, to oversee the start of proof machining work on the first wheel shown, in the initial set of photos was made.
The ‘proof’ bore through the centre hub and the crank pin boss will follow.
Non Destructive Testing (NDT) will be applied to each wheel to determine if flaws or imperfections are present and if detected these can be pin pointed for detailed investigation and further action. Tests will involve Magnetic Particle Inspection (MPI,) Radiographic Test (X-ray,) Ultrasound Test (UTS) and Final Inspection Measurement, leading to the product release. The Trust will then arrange final machining to precise sizes and tolerances in accordance with the design requirements.
In the meantime, machining of the Hornblocks at CTL Seal has commenced.