A status report
At the end of August, following the removal of the J72’s inner firebox, Douglas Pegler, from our insurer Bureau Veritas (BV), met with Paul Hutchinson, and with Danny Dymott from Northern Steam (NSEL), to present the proposed form of repair for the J72 boiler.
A key decision, given the extent of the work required, was how the repair would be classified (i.e., was it a like for like repair, or was it a new design needing to be submitted to an approval process?). Whilst there will be some welded elements to the boiler barrel and outer wrappers, verification of the boiler will be demonstrated by working to the 1949 J72 boiler drawing. BV has confirmed that the work constitutes a repair.
On the basis of this insurance examination, NSEL is to provide costs for the additional elements in relation to the copper firebox and outer steel firebox. In terms of the copper renewal, we are seeking prices both for a complete renewal of the sides and crown as one piece of copper, and for an option to retain the copper crown with side sheet renewals. The copper backhead is in good condition and is to be retained. We are also looking to retain the outer steel crown, subject to NDT testing. The dome has been removed from the old barrel and minor welding repairs to the dome will be required.
Once these costs are received, we will be in a position to evaluate their impact in relation to the project costs, present these to the Trustees for acceptance, which in turn will allow the preparation of a motion for members to (hopefully) approve the necessary additional expenditure.
Pattern making by South Lincs Foundry (SLF) has taken longer than expected, but should be complete, by the time you read this. Consideration of the chemical composition of the casting itself continues, with input from a respected metallurgist.
Material costs for the casting itself have increased, in common with increases across the engineering sector. However, on recalculating the volume of the pour, SLF has found that it exceeds their capability and the actual casting will be subcontracted by them.
Good progress has been made on fixing the fitted bolts (both plain and countersunk types) to the horn guides. The horn stays are being welded up and machined back to size, to deal with some slackness in the fitting.
The axles have had a UAT (Ultrasonic Axle Test) carried out. This is to check for any cracks in the axle and under where the wheel is pressed on. They have also been tested using Eddy Current - this is to test for any surface cracks in the axle. All results came back clear.
A number of other parts requiring NDT have also passed testing.
The wheel sets have been prepared for transportation and are now ready for despatch. Potential contractors for the tyre turning and boss face skimming are being considered.