Let’s get 4561 rolling

29th November 2021

A problem was found when the second piston rod was set up for machining. In the picture it is shown with a square standing on the piston head. You will notice that while the bottom of the square is in contact with the piston rod, above this there is a tapering gap between the rod and the rest of the square. This indicates that the piston head is not square to the piston rod as it should be.

It is not known how or what caused this situation but for future safety the decision has been made to replace both the piston rod and piston head for which quotations are being obtained pending approval to place the necessary orders.

Work has progressed in aligning the cylinder slide bars which have now been finally fitted with the requisite bronze packing pieces fitted between the fronts of the bars and the rear cylinder covers and also between each slide bar and its companion slide bar bracket.

Work has continued machining the new cylinder cock castings. The photo. shows how each casting is mounted in a lathe to enable the machining of centre section, which will house the actual valve when fitted. Each of the six cock castings is being machined stage by stage for conformity and to ensure that each is dealt with in the same manner where any awkward setting up is needed.

 

 

27th October 2021

A welding procedure was devised to satisfactorily repair the cracks previously found (see 9th August).

Work continued on the horn faces of the 6 coupled wheel axleboxes ready for the new bronze liners to be fitted after a delay waiting for them to be delivered. Each axlebox horn guide has been fitted with a new liner on the main bearing face with smaller liners on the front and rear thrust faces. The 6 axleboxes are seen here ready for these liners to be riveted on ready for machining to match the main horn blocks on 4561’s main frames. Also seen are the six new axle bearing bronzes.

The first of the new cylinder cock castings is seen as set up in the lathe ready to face and bore the main mounting face. Each of the six cocks will be so machined before going on to the next stage of machining the bodies.

One of 4561’s two piston rod assemblies is seen as set up in a lathe for re-grinding smooth over the length which slides through the piston rod gland in the locomotive’s rear cylinder cover. Following this the piston head can be machined to provide a running fit in its associated cylinder. The piston heads which have been recovered are being re-used but are now oversize  having previously been machined to suit the old worn cylinders that have now been replaced.

Interestingly, one of the piston rods is stamped ‘4561’; the other is from ‘5539’.

 

9th August 2021

The unwanted studs have been removed from the axlebox horn faces (see previous notes) and the holes filled with plugs screwed in and capped with weld to provide a new bearing surfaces. The stud holes that are required have been re-threaded and the horn faces and side cheeks dressed smooth as seen here.

Unfortunately this process has exposed some cracks in the angles between the faces and cheeks in four of the axleboxes. We now have to determine the procedure most suitable to enable repairs which, as the axleboxes are steel castings, is likely to involve welding.

Polishing the outer faces of the axleboxes has revealed a little of their history. It was general practice to stamp all main components with the locomotive number to which they were fitted. This is a sample showing that this axlebox was the Right Leading (RL)  on a particular 45xx originally followed by use on at least 2 55xx locomotives.

Part of the axlebox refurbishing process is the removal and re-metalling of the white metal wheel bearing surfaces. This shows ‘work in progress’ on one box where the white metal is being melted off using a gas torch. Care is taken to recover the white metal as it can be used again if not too contaminated or sold to a scrap merchant as it is relatively valuable. The axlebox faces will be re-metalled and machined to fit the axles once new bearing bronzes have been fitted.

The picture shows the front platform of 4561 in place using the original platework. Owing to the condition of the centre section this will be replaced with new but the side sections can be re-used and made to fit the slight variations in dimensions as a result of having fitted new frames under this area.

Owing to their condition the 6 cylinder cocks are going to be renewed. The picture shows one of the old cocks with some used fittings on the right and 4 of the castings required (3 on left plus a new valve on right)  which have yet to be machined for use.

New cylinder drain cocks cost around £400 each and we need 6 of them.

Can you help?  Please donate what you can.

 

18th June 2021

Having considered the options for the refurbishment of the coupled wheel axleboxes it was decided that the existing bearings and horn liner bronzes were beyond recovery and should be replaced. The unwanted 12mm holes will be plugged and sealed and the 3/8” BSW holes refurbished to allow the new liners to be fitted as originally intended.

This proposal was put to the WSRA Board for approval of the additional costs expected to be involved before placing orders for the supply of new bronze bearing castings and the liner plate materials.

Meantime the 4 crosshead slidebars have been refurbished and polished before being fitted in their respective positions on the support brackets (or ‘G’ irons) behind each cylinder. This enabled their alignment to be checked as parallel to the cylinder centre datum wires; and to ensure they are  correctly spaced to determine the thicknesses of bronze packing pads to be fitted both at each ‘G’ iron and at each rear cylinder cover before being finally bolted in position.

Shown are the two RH slidebars in position parallel to the datum wire. It is just possible to see the gap between the lower bar and the cylinder cover for which a packing pad is needed. It is also just possible to see the end of the top bar has been stamped ‘5553’ which is the locomotive no. on which this bar was first fitted by the GWR

This is another view of the RH side showing how the slide bars are supported by the ‘G’ irons to which they are bolted by the bolts recessed into each bar. The outer end of the lower bar top surface has a sloping flat machined into it to provide an adequate running clearance from the connecting rod when fitted. This is not required for the upper bar owing to the cylinder centre line being 2 ½” above the driving  axle centre line.

This photo shows the LH slide bars have also been fitted. Again it is possible to see the gaps between the front of each slide bar and the rear cylinder cover lugs waiting for their respective packing plates.

27th May 2021

Mention was made earlier about the datum wires which have been set up at each cylinder bore centre line from the front of each cylinder to behind the rear coupled axle location. In addition ground steel datum bars have been set up at each coupled axle centre line on mounting blocks carried between each pair of horn blocks. These datum bars have enabled checks to be made to ensure that the coupled axles will be located square to the frame plates at the correct distances behind the cylinder centres and from one another. They have also enabled checks to be made that the cylinder centre lines are 2 ½” above the coupled axle centres. (This is a design peculiarity of Churchward locomotives).

 The design heights of the coupled axles within the horns had previously been stamped on each frame plate during assembly. In the photo. above the square has been mounted at a datum point (circled in chalk) to enable the cylinder centre line height to be confirmed.

 With confirmation that all key dimensions have been achieved the remaining fitted bolt holes can be reamed and the bolts made and fitted. The datum wires and bars will remain in position as a basis for horn cheek grinding to designed sizes and the subsequent machining and fitting of the 6 coupled axleboxes.

As a next step a start has been made on making up the new cladding sheets for the cylinders. The photo. shows the main wrapper plate on the LH cylinder cut to size and shaped to fit the cylinder casting held in place with setbolts screwed into the front and back flanges. Ultimately this plate will encase the cylinder insulation when fitted.

Work has started on preparing the axleboxes for further use. They had bronze liner plates screwed to each horn face which were fitted to make up for past wear and tear. These in turn have become badly worn and require to be replaced. In the example shown the liner has been removed and revealed that apart from the stubs of the fixing screws yet to be removed there is also another set of unused screw holes. These are the correct 3/8” BSW thread form whereas the screws used appear to have a 12 mm Metric thread. A common standard will be adopted for the fitting of the 6 new sets of liners.