7820 Dinmore Manor - The Blog

This blog will follow the heavy overhaul of 7820 through to its return to steam. The chassis is being overhauled at Tyseley Locomotive Works whilst the boiler is being overhauled at Ian Riley's workshops.
We are working hard every weekend to bring together the hundreds of small pieces that require refurbishing to get the loco back into working order. Follow us to keep up todate with the weekly progress and who knows if you like the look of what you see you may even be tempted to join us and help put 7820 back in action.

Sunday 29 January 2012

Tyseley working party 28-01-2012

Front sandboxes being cleaned down ready for painting.

Dissolving 10 years of oil and grease off the sandboxes. At least they haven't rusted!

The driving wheel axle boxes have had new bronze liners riveted in place. The plates are then machined to give a perfect fit in the horns.

Whilst work continues on overhauling 7820 our running loco 3850 has not been forgotten above is the refurbished tender clevis rescued from one of the unrestored tenders. This will be fitted to tender 1761, which is currently running behind 3850, as the existing one is showing signs of wear. A straight swop will be quicker than removing the old one, refurbishing it and then refitting, thus ensuring 3850 remains available for traffic.

Lastly the refurbished (new bushes and grease nipples) weighbar shaft bearings ready for refitting to the frames with the shaft which will enable the inside motion to be installed after re-wheeling.

Monday 23 January 2012

Repairs continue in preparation for re-wheeling

Making new bushes for the T-links in the lathe. These are made from thick wall tube of the appropriate grade skimmed down on the outside to have a few thou interferance fit in theT-link hole and machined out internally back to drawing size ready for new pins.

New bushes are pushed into the T-links using the flypress. The old bushes and pins were worn oval from 80000 miles supporting the weight of the loco.

Refurbished T link ready for use in the bottom of the axle boxes. The new pins shown in an earlier posts (19th Dec and 10th Jan) fit through the top of the T link and connect the link to the axle boxes, with the bolt seen in the above picture locating in the dimple machined in the centre of the pin.
Meanwhile the leaf springs hang from a pin (yet to be made) which passes therough the buckle in the centre of the spring and the new bush in the lower end of the T-link thus connecting everything together.

Wednesday 18 January 2012

The boiler, a little history on the wear and tear found!

The boiler for 7820 came out of Barry with the locomotive. In order to get it steaming again in essance all that was required was replacement of the tubes, some stay and rivet replacement and off she went. Having completed a ten year ticket and never having had a major overhaul since BR days certain areas of the boiler had reached the end of their life. The photos below, whilst looking like a horror wall, show the issues which arrise in an old boiler and need adressing periodically. Whilst these more major repairs do not occur every ten years like tubes, stay and rivets they are longer term repairs which have to be addressed.

The main area of repairs on the copper box has concentrated on the laps. After years of tooling and caulking the laps get thin and eventually they crack at the weak points around the rivet holes. Here you can see how two holes in the door plate have cracked out to the edge of the plate.

At the lower edge of the door plate rivets connect the inner door plate to the foundation ring and the outer plate. These rivet heads waste away over time and are replaced at overhauls if the heads have reduced beyond acceptable limits. Each time a rivet is replaced more strain is placed on the platework as the rivet cools and contracts. In addition each time the loco boiler goes through a heat up and cool down cycle or a fireman misses a bit of the grate and the fire goes thin resulting in cold air being drawn in to the fire box more stress is placed on the platework. All this stress shows up in corners and around fixing points such as rivets, stays and tubes. Above the result of all that stress has manifested itself as a crack radiating off from a foundation rivet hole.

The above shows a very wasted and thinned section of lap. The only solution here is to cut out the offending section and then weld in a new section restoring the material back to its proper profile. Quite a lengthy and costly process when you take into account the cost of copper, the intricacies of welding copper and the labour involved in shaping the plate and redrilling the holes to line up with the sister plate.

As mentioned above with all of the heating a cooling cycles a boiler goes through it moves, each time it moves parts flex, repeated flexing of a component causes fatigue and eventually stress cracking. The above photo shows the cracks from the stresses occuring in the tube plate where one element is restrained by the tubes and the other is riveted to the side plates.

Moving onto the steel firebox, this has not escaped from repeated stressing. Above a crack in the throat plate can be seen after polishing of the steel to make it show up. Again this has occured at a corner where stresses are concentrated. Taking into account wastage and grooving found in the remainder of the throat plate, the decision was taken to manufacture a new throat plate. More on that later.

Lastly; probably the worst bit of copper lap I have ever seen. What was originally a thick piece of copper has been reduced to fresh air leaving little material around the rivet heads. Again time for a new section of lap.

Monday 16 January 2012

Progress at Tyseley on 7820, motion and other parts.

With the rear half of the frames ready for wheels attention turns to the front end. The bogie will come out for overhaul at the same time the main drivers are installed.

Meanwhile by the container work continues on cleaning, checking and painting the hundreds of motion parts ready for reassembly.

Some parts reqire more cleaning than others, here one of the spring hanger dics is subject to heavy duty cleaning.

The copper pipework is all being cleaned in preparation for annealing. This process softens the copper preventing vibrations, which it is subject to whilst in use, from causing cracks to form in the pipes.

Is that green topcoat I see on the rocker arms? Is this a clue to the livery or a plot to fool everyone and actually it will go black..........

In the sunlight you could be mistaken and think we are overhauling an LNER loco.

Friday 13 January 2012

More progress towards re-wheeling

More progress has been made towards re-wheeling 7820 with the production of new spring hanger bolts to replace those which were found to have corroded beyond being suitable for reuse.

Thanks to some hard work by volunteers and their associates some of the existing nuts were salvaged for re-use. It all helps to keep the costs of a heavy overhaul down.

Tuesday 10 January 2012

Return to work after the holidays.

The lads get back into the cleaning and painting of the cladding. Work on most of the small pieces has now reached the stage of undercoating with the final two large pieces of cylinder cladding being cleaned and prepared for paint in the shot above.

Meanwhile in the workshops the axle box pins were being completed. Here one of the new pins in being pilot drilled using a gash bolt in the T-link to keep everything centered.

After pilot drilling the pin is removed from the T-link and drilled to put a lead on the holes

The result: 6 new pins ready for the dished hole for the securing bolt to be machined in.

The last operation using a specially ground shaped cutter to make the dished locating hole for the securing bolt.

At last the six new pins are finished and ready for installation when the loco is rewheeled.