- With the engine’s frames erected, all the major frame stays, brackets, horn blocks, axle boxes & buffers have been cast and fitted using around 1,000 driven bolts. With the tender tank undercoating complete it has been possible to remove the wheelsets from under the engine frames. This has permitted fitting of the remaining driven bolts and cold turned rivets in the outside motion brackets and the spring hangers.
We now have the profiles for the “shelf” under the back of the cab and Ian Matthews has started making some special tooling to facilitate hot bending of the 20mm thick plate to form the flanges on each end which mate with the outer Cartazzi frame plates. Normally, shaping like this is carried out cold using a brake press forming a series of small bends, however, the radius required in this case is equal to the thickness of the material necessitating the bending to be undertaken at red heat. In this condition the metal, which is 20mm thick, will be sufficiently pliable to be bent using form tools in our 30ton press. As it is important that the finished article is a good fit between the outer frames, doing the work in house as opposed to by a plate bending firm will enable subtle adjustments to be made to ensure a tight and parallel fit.
The "shelf" bending jig - Leigh Taylor
When fitted to the frames, the shelf will complete the frame structure and enable Ian to start fitting the electrical trunking under the cab which is relatively complex as the 3D CAD view shows.
3D CAD view of the trunking on the shelf. – Alan Parkin
- Steady progress with the tender frames continues at Ian Howitt’s works at Crofton. The initial machining of the hornblocks has been completed, the hornblocks dispatched to NVES in Darlington for welding on manganese steel liners (NVES, thanks to our activities over the years, maintain a welding procedure for welding manganese steel to cast or mild steel), and are now back at Crofton for final machining. Many details for the brake linkage and hand brake mechanism have been made including the brake cross stay and brake cross shaft.
Tender hornguides with manganese steel liners welded in place. - Daniela Filová
The hornguides being set up on the tender frames. - Ian Howitt Engineering