OVERHAUL 2015 - 2022
Notes from information supplied by Darrin Crone, Locomotive Engineer.
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January to March 2017.
26 March 2017
Painting has now progressed to the application of white gloss on the inside of the mainframes. As the frames are being painted work has continued away from the loco for most of the week. The superheater has been revisited this week with the studs examined to see if they are suitable for further use. The wasted and worn ones were removed and the good ones die-nutted to clean the threads. The superheater flanges were cleaned off and the cover plates retrieved from store for inspection and cleaning. Meanwhile the bogie frames have received further needle gunning.
The safety links removed from the tender last week were stripped of paint this week, descaled and wire brushed. After cleaning up they were measured and the results tabulated on a copy of the LNER drawing. The main tender drawbar pin received similar treatment.
The air pump overhaul continued with the inspection of the piston rings completed. We had hoped to hone some of the marking from the cylinders this week with the honer borrowed from NELPG, however our drill broke on another job so elbow grease and abrasive paper were used instead. The coupled horn lubrication oil boxes and pipes were retrieved from store. The pipes and oil boxes received a final cleaning and the oil boxes were fitted to the loco on Friday. The steam sands filler guards have also now been fitted.
Now that the gauge frame refurbishment has been completed we have moved on to the clack boxes. The main clack seat in one of the clack box castings is worn out and requires replacement. We tried to get it out while on the loco but it wouldn't budge so will have to be machined out. We have a replacement ready to go in.
The replacement of worn fasteners continued this week with a fitted bolt in the trailing right hand hornblock casting. The hole was reamed last week and the new bolt made this week. However the surface of the casting was very uneven resulting in little surface contact with the nut on the bolt so the spotface was re-cut. The new bolt has now been fitted. A similar worn fitted bolt was removed from the leading right hornblock casting and the hole reamed. Again the surface under the nut was poor again requiring the spotface to be re-cut.
At the front of the loco reaming of the cylinder holes began this week using the boring jig used over the last few weeks to dress the holes true. The reaming is done by hand and is hard work but the Engineering Team have now demonstrated that the method we are using will produce very good holes.
The final set of coupled wheels was receiving final profiling at the South Devin Railway by the end of the week. The new lining plates for the thrust faces of the bogie wheels have been made and are ready to fit. At Llangollen the steel for the left outer wrapper side of the boiler is being fitted and the heads of the right hand combustion chamber stays have been removed.
19 March 2017
The bogie has been out of the news recently so it's time for an update. The bogie axlebox inspection has now been completed and we await the report from our CME. He has now moved on to examine the bogie horns. The bogie frames have been needle gunned and the outside of the frames are down to bare metal. There is still work to be done on the inside of the frames before they can be fully examined.
The combined brake and spring bracket is doing very well at the works of K D Flavell. It has now been removed from the borer and will be put on a milling machine to do the final skimming of the bracket edges. The boss that holds the brakeshaft bearing is now true to the bracket section and the bracket is truly flat and square. The recess in the lower side of the bracket which accepts the Spenser spring box is yet to be rebuilt with weld and machined, however we were very fortunate that due to the careful machining of the boss section that this can now be retained without building up or replacement. During inspection at Flavell's a number of cracks were found in the bracket and these have now been repaired. When the bracket is completed it will again be fully examined for defects before refitting to the loco.
The pistons have been measured accurately and examined for defects. It was decided that one of the tapers that fits in to its crosshead could be improved by a little lapping to remove some marking. So with the piston rod stood vertically the overhead crane was used to support the crosshead and it was carefully lowered on to the rod. A little fine abrasive paste was put on and the crosshead carefully rotated. The lapping immediately showed good contact between the rod and crosshead and that the marking would not affect the fit.
As the boiler overhaul progresses apace in Llangollen we are working our way through the refurbishment and repair of the boiler fittings. We must make sure that these are completed for when Llangollen need them for reassembling the boiler. This week the gauge frame refurbishment was completed. This has included the replacement of one of the gauge glass fanged valve units along with most of the gauge glass nuts and some of the plugs. All new spindles have been made and new packings fitted. They look good enough to put on the mantelpiece. I did get a shock though when I couldn't get our gauge glass spanner to fit the nuts. However when I cleaned up the spanner it fitted perfectly. We must remember not to keep the spanner on the warming shelf where it gets covered in grime that then gets baked on.
The right hand splashers were fitted this week. They required some shimming under the end brackets as the right hand footplating slopes very slightly down toward the loco frames. The old packings were discarded as they were unsuitable for further use so new single piece packing pieces were made. They fit perfectly. The assembly of the splashers was completed by putting in all of the remaining fasteners. There are pipe clips to put up on the splashers and a start has been made on this.
Painting at the ends of the loco continues. The repaired brackets in front of the 2:1 lever stretcher were painted this week, only leaving the back of the front bufferbeam unpainted. By the end of the week the inside of the frames have been rubbed down ready for undercoat. At the back of the loco the dragbox has been primed. As part of the dragbox refurbishment we are also now examining the intermediate drawbar and safety links and their pins. These have now been removed from the tender.
The air pump overhaul continues with examining and cleaning the atomisers and testing the lubricator. All of the studs were removed from the steam cylinder and this has now gone for contractor repair.
The boring of the cylinder bolt holes continued this week with excellent results. There are only a couple of holes to do that are accessible with the present jig, then there are three to do that will require a modified set up.
12 March 2017
The dragbox bolting has been completed with the last couple of nuts torqued up. The dragbox was then di-pen inspected. Not an easy job on such a complicated component so one level at a time was done. The areas around the draw bar and safety link pins has also been inspected and no defects were found. Then on Friday the first of the primer was applied.
The safety critical air brake components were retrieved from store this week. They were given a clean up and we made sure the ports were sealed. These will be sent away for contractor refurbishment so that when they are returned to us they will carry certification and a guarantee.
There is still painting continuing of the loco frames and major castings around the front of the locomotive. The final coat of gloss was applied to the outside front bufferbeam area. Priming continued of the middle cylinder and the saddle casting.
The boring of the cylinder mounting holes in preparation for reaming continued this week. About half are now completed, however there are some particularly awkward ones yet to do. Depending upon the amount of reaming the cylinder flange holes require we may have to revisit them with the borer, but we will see what we get when we ream them.
The coupled wheel springs were given a clean off this week and the spring buckle pins and retaining boxes removed. The springs will be sent for contractor refurbishment and quotes have been obtained. The pins and retainers were tagged and put in store, and a start made in moving the parts from over the adjacent pit in to the GUV. We are clearing this area as it is planned to move the tender in to this space. Other parts have been moved to the other side of the loco.
In Devon the wheelsets are progressing with the crank axle on the wheel lathe. At Crewe the tubeplate has been formed and will be sent for machining shortly. Repair work to the firebox copper side sheets continues at Llangollen and an access platform is being assembled so that work can commence on the top of the firebox.
The splashers on the left of the locomotive were refitted this week. As they are secured with dozens of bolts it was decided to fasten them by bolting through every other hole for the present. When they are all up we will put the rest of the bolts through.
During inspection of the air pump it was noticed that the clack valve springs show signs of wear, so it is planned to replace them. A suitable, commercially available spring specification has been identified. The cylinder end covers have now been di-pen inspected and no defects were found. That just leaves the steam cylinder requiring repair and the other cylinders will be honed to clean them up. The studs are being removed from the steam cylinder to aid repair.
The pistons have received a detailed inspection prior to their refurbishment. Particular attention has been given to the end of the piston rod where it meets the head and to the cotter slot and taper that fits in to the cross head. No cracking was found but one of the tapers shows some marking. This will have to be carefully removed.
5 March 2017
I visited the works where the combined brake shaft and spring hanger bracket is to be refurbished. We have produced a drawing showing the dimensions we need to match the position of the corresponding bracket on the other side of the loco, ensuring that the brake shaft crosses the frames squarely and at the correct height. During the week the section of the bracket that mates with the loco frames was removed and replaced with new material. By the end of the week the bracket was placed on a boring machine in preparation for machining.
The air pump overhaul continued, with NDT inspection of the piston rod and the three cylinder castings. The steam supply flange on the steam cylinder casting was found to be in poor condition with pitting across its face so it was put on the NRM's borer and the face skimmed. As a result of the inspection it has been found that the steam cylinder will require further repair work.
The tops of the frames and splasher brackets are now finish painted by the volunteer Painting Team. The middle cylinder front and under the saddle has also been prepared so that high temp silver can be applied. The 2 to 1 lever stretcher was di-penned this week after some needle gunning in some of the hard to reach corners. No defects were found and it has now been given a coat of primer. On Friday the front bufferbeam area received a coat of top coat black gloss.
The bogie axleboxes are now subject to detailed measurement and inspection. As the bogie wheels have been re-tyred the final sizes of the journals will soon be known and the bogie boxes can be made to suit.
Under the saddle casting we are replacing a number of worn out fitted bolts that go through the frames and cylinder flanges. Due to the restricted space and to ensure correct alignment of the repaired holes we decided to start the holes by boring them before final finishing with a reamer. So we have devised a boring jig which was trialed on Thursday. The method we have devised was proved with a hole bored in the saddle casting on the centre of the hole in the cylinder flange. This will ensure a finished hole with a centre line through the saddle, frames and cylinder flange truly perpendicular with the loco frames with the minimum amount of material removed.
In front of the 2 to 1 lever stretcher there are two angle brackets that at some time were cut through, presumably to remove the front plating above the front bufferbeam. We are guessing but it may have been during straightening out the front of the loco after a prang. The rough cuts in the brackets were welded back up equally roughly from underneath, so presumably the footplating in front of the smokebox was left in place. As we can get to the top of the angles these were welded, and also a crack in the left hand bracket found during the inspection of the 2 to 1 stretcher.
The studs that hold the front buffers on bottom-out on the castings behind the bufferbeam, This allows undue stress to be put on these castings when tightening the nuts on the studs when fitting the buffers, so the studs have now been shortened so that they correctly stop at the thread run-out on the studs. The nuts have also been loosened so they can be removed from the studs so that studs and nuts don't act as bolts.
The descaling of the dragbox was finished this week and I doubt that it has ever been so well finished, even when it came out of the foundry. We will NDT it next then paint it. The final three dragbox fitted bolts were machined this week then jacked in to position. The temporary nuts have been removed from the existing fitted bolts and the permanent nuts put on. To ensure that we provide maximum protection against corrosion for the bolts, particular attention has been paid to prevent any further water ingress between the dragbox, bolts, nuts and washers. Another fitted bolt made this week was driven home and secured, this one to the middle cylinder slidebar stretcher.
26 February 2017
Painting of the frames continued with, by the end of the week, the primed outside frames receiving a rub down prior to their first coat of undercoat. Work has also concentrated on finishing the footplating in preparation for the refitting of the splashers.
The buffer housing threads to secure the backplates have now been repaired and the plates have been fastened on with countersunk screws, as originally fitted.
The tender was worked on this week as the refurbishment of the loco dragbox job also includes the inspection of the intermediate draw bar and safety links. However, due to the location of the tender in the workshop we are unable to do much, but it is expected to shunt the tender in to a better location in the next couple of weeks. A start was made cleaning out the dragbox on the tender front.
We have previously had sessions of riveting the splasher brackets to the frame tops, however some rivets could not be put in due to the inaccessibility of some of the holes. We borrowed a compact hydraulic rivet squeezer but unfortunately it lacked the power we needed, so we decided to attack the problem from the opposite side of the frames. The original arrangement was for rivets to be held up from the inside of the frames and closed or hammered down from the outside. Holding up from the outside meant using countersunk rivets, however the countersinks on the outside of the frames were in poor condition so using this side meant first repairing the countersinks. A special countersink had to be manufactured to give us the correct form and this was used successfully a couple of weeks ago. Next we needed rivets, but standard form countersunk rivets did not have heads big enough to fill the countersink and allow them to be held with the equipment we have. So special rivets were made from the same material our rivet manufacturer uses. As the clearance we have is small a special attachment had to be made to go in the equipment we use to hold the rivet head in place. This perhaps give you some idea what is involved behind the simple statement that we have riveted the splasher brackets back on.
The riveting team was assembled on Wednesday. The team required 5 people, this may be a surprising large number but we had one on the torch heating the rivet, someone on the tongs to move the rivet to the hole, another to knock the rivet in the hole allowing the tongs to get out of the way, someone to put the jamback in place to squeeze the rivet head in to the hole and finally the riveter to close the rivet with the hammer.
While riveting the splasher brackets on Wednesday we also replaced two rivets in the dragbox. One was 3/4" and one 7/8", which closed up very easily, a relief after the time it takes for setting up. We must thank the riveter for allowing us to use his riveting equipment and also for his foresight in saving it from the scrap man once the shipyards on Teesside ended riveting.
The countersunk side of the rivets, splasher and dragbox, were finally ground flush. The splasher brackets were cleaned and then given their first coat of primer.
The left leading hornstay returned to York on Saturday after repair and was refitted. The hornstay was returned by the repairers transport so as a return load the leading right combined brake and spring bracket was put on the van for taking to Teesside for refurbishment. After the hornstay was replaced the frame jacks were repositioned under the centre of the frames.
The coupled wheel tyres are currently being turned and our repairer was planning to light the hearth for heating the first tyre by the end of last week. As reported previously the bogie wheels have already been re-tyred.
The dragbox has received more descaling this week, with only the bottom underside now requiring finishing off. As the top is finished the first two fitted bolts were put in this week. The holes were accurately measured and the bolts made to give the correct fit. Because of their inaccessibility they couldn't be knocked in so had to be jacked. As the bolts are long and the jacks have short strokes it takes a long time to set up, jack the bolt and then insert more packing and start to jack the bolt again. A middle slidebar stretcher fitted bolt identified as requiring replacement during the frame survey was removed for replacement this week and reaming of the hole began.
19 February 2017
The RH buffer sleeve put in the lathe last week has now been finished. Very impressed by the result the LH was similarly treated. The surface skimming also involved restoring the internal radii that matches the back of the buffer head. After taking a couple of photos the ends have been taped up to protect them until refitted to the loco. We must thank Dan Holmes of the NRM for allowing us to put the sleeves on his treasured Holbrook lathe and operating the hydraulic copier to ensure accurate machining of the end radii. The buffer housings have backing plates that are screwed on to the housings. The threads on the housings have either been re-tapped oversize or have broken screws in the holes. This week the repair of the holes was started with the welding up of the oversize holes so they can be re-drilled and tapped.
The refitting of the steam sands filler pipes was completed this week. Like many parts around the engine they have been examined and repainted off the loco. Particular care was taken to ensure that water can't get into the sandboxes so new seals and packings have been fitted. Fitting also ensured that there is clearance around the pipes where they go through the frames to ensure no chafing in traffic. Very elegant they look too, much better than on another Gresley Pacific we have recently shared workshop space with, which has angular looking fabricated pipes.
The air pump overhaul began in earnest this week with the air pump being moved on to a bench where dismantling and examination began. Preliminary examination shows little apparent wear to the cylinder bores, but it is early days yet.
The countersunk rivets we need to finish the riveting of the splasher frame brackets were made this week. The long ones for the double frames were machined last week.
The saddle casting was "signed off" last week by our CME, subject to some minor repair work. This allowed the painting team to work on it. After a brief visit by the needle gun a coat of high temp silver was applied. The rear flange of the saddle has been left unpainted as there are numerous holes from fastening down the smokebox, not all used, so they will be welded up and re-drilled after the refitting of the boiler.
Meanwhile in the dragbox descaling has continued. Originally planned to be a final descale around the existing bolts to ensure a good base for the fitting of new nuts, the results have been so good that it has been extended to the entire dragbox casting. It is worth doing as the cleaner we can get it and then get it painted the longer it will last. The good surface finish will also now allow a more reliable di-pen examination.
The horn castings have now all been examined and di-pen tested with the last one completed on Tuesday. The painting team were straight on to the castings and they have now all been primed. Painting continued between the frames this week. On Saturday the repaired leading right hornastay returned to York and was refitted by our junior volunteers, The 007 Gang, under the guidance of our CME. With this refitted the leading left was then removed for repair.
12 February 2017
All the footplate rivet holes have now been repaired and are ready for new rivets to be fitted, except one. The one outstanding hole is in the corner of a bracket which, though detailed as riveted on the LNER drawing, it is impossible to get a rivet of sufficient length in. The hole had a bolt in it welded to the footplate which was clearly not original. So it's a mystery how the LNER did it. The repaired holes have been drilled and countersunk back to the size detailed on the original LNER drawings.
We are now ready to fit new bolts to the dragbox and new nuts to the existing bolts. Suitable washers to match the full size Whitworth nuts were finally delivered this week, too late to be fitted. In preparation the top of the dragbox was cleaned and the needlegun used to remove scale from around where the new nuts will be fitted.
Painting continues with the frames in front of the cylinders on the outside being primed. The Paint Team has also painted the front bufferbeam. The front coupling hook housing was removed again this week and was painted. The housing shows wear, which is to be expected. This will have to be measured to examine if the wear is acceptable or requires repair. The inner sleeves of the front buffers are now being examined and refurbished to remove the decades of wear they show. The first one was put in the lathe to check for straightness and front section carefully was skimmed to remove surface marks and impact damage.
The exhaust silencer for the air pump was inspected then primed this week. The drain valve on the bottom of the silencer was stripped, cleaned out and examined. On the subject of examination, five of the six coupled wheel horn castings were inspected. The painters will be pleased to know that these can now receive their attention.
The splasher bracket rivet holes in the frames were finished countersunk with a special tool made by the Engineering Team. It worked very well and the finish of the holes is now suitable for the fitting of countersunk rivets. The rivets will have larger than normal countersunk heads so have to be specially made. The longer rivets for the brackets which are attached to the double frames were made on Saturday.
The middle cylinder cover holes received a final clean out this week, now that all the studs have been removed. They have all been inspected and are in good enough condition for new studs to be fitted.
The overhaul of the air pump began this week, after extensive cleaning over previous weeks. Engineering Team volunteers have done a great job in information gathering and we have photographs from the last overhaul. This week it was decided that we must first find a spot in the workshop where we can dismantle the pump and layout parts without them being disturbed, so an area was identified and agreed with the workshop management. The area will be cleared and the air pump moved.
5 February 2017
The last two middle cylinder cover studs were removed this week using the drilling jig. The jig has proved to be very effective in directing the drill down the centre of the stud accurately. One of the final two stud threads was actually removed intact. The stud holes now need cleaning out and new studs can be fitted.
One of the most noticeable changes to the appearance of the loco this week was the silver priming of the outside cylinder castings. Its certainly eye-catching. The Painting Team continued work around the footplating but also putting gloss top coat on to the air pump bracket.
The mechanical lubricators, axlebox and cylinder, were returned to the workshop from storage this week for overhaul. They had been cleaned before putting in store but they have required some further attention this week when the ratchet mechanisms were opened as they are packed with grease. Wear to the pawls is evident, to be expected. Both sets of pawls will be carefully refurbished to ensure future correct operation.
The dragbox spotfacing continued this week. It was difficult to get a good finish on a couple of the holes so a single point cutter was made and did a good job of leveling the spotface on the remaining holes. A spotface cutter mounted abrasive disc was also made to give them a final polish. The sharp edges of the holes were removed on Friday and we are now ready to fit new bolts.
While priming continues on the footplating we have also been removing the remaining loose rivets and welded up bolts in the footplating on the left hand side. Loose rivets and bolts left in place wear their holes and countersinks meaning when removed the holes need work to repair them before we can fit new fasteners. Some have been redrilled and worn so much over the years that they require welding up and remaking. Some of the holes were welded on Saturday.
This week the steam sandbox lids were refitted with new chains. A new eyelet for attaching the chain to the right hand lid was copied from the remaining one in the left hand, which looks to be part of the original lid. Also this week a new stud was made for the trailing right brake hanger bracket. The old stud was too short to take a full nut and be pinned, and when removed from the frames the stud was substantially shorter than the other studs used for securing the brackets.
The last sections of mainframes were inspected this week prior to painting. Careful inspection was made around the leading sections of the frames and front bufferbeam, where the loco may suffer from impact damage. No defects were found. Still on the subject of frames the horn castings are being subject to detailed inspection. The inside top corners, where the horn liner lubrication is introduced was detail cleaned and the lubrication pipe bushes were removed and oil ways cleaned.
29 January 2017
The boiler was visited this week at Llangollen by our CME, Richard Swales and myself. At Llangollen we met with our Engineering Team volunteer Paul Aston. Paul is doing a great job of interfacing with the Llangollen Engineering Team and provides weekly reports and photographs so we are very well informed of progress. During our visit we also met with our boiler insurance surveyor, the Llangollen Railways's head of engineering and their boilersmith.
Work on the boiler is now well underway and it has been moved in to the boiler shop, from the main workshop area, where work was initially being carried out. Sections of the outer wrapper and outer doorplate have been removed and stays drilled out. Some of the stays are at maximum size now so the holes will require welding up. As you may know each time a stay is replaced it is normal practice to increase the size of the hole as the threads need to be cleaned up to ensure a good fit between plate and stay. So as a boiler is re-stayed during its life the stay threads get bigger. This is permissible up to a certain maximum size at which the holes need to be closed up, normally welded, and remade.
Work on the boiler has also included progress with the removal of the firebox tubeplate. The tubeplate is secured with patch screws and has been seal welded in. The weld and patch screws are in the process of being removed. After visiting Llangollen Richard Swales and I went to LNWR at Crewe to see work on our new copper tubeplate. The tubeplate has been cut out from plate and has been machined to reduce the thickness of the flange, as specified by the manufacturing drawing. It is now ready for forming. On our visit it was on the former ready to be shaped.
While considering progress away from York, we have been in contact with our wheel repairers at Buckfastliegh. Work progresses on the wheelsets with the bogie wheels being on the lathe with further machining to remove the lining plates while the coupled wheels are receiving some repair work.
At York work continued with the removal of the middle cylinder studs. There are only two studs remaining that will require cutting off before they can be drilled out. A guard has been made to go round the studs to make sure when the studs are cut the face of the cylinder casting is protected. Also competing for space near the middle cylinder work continues on preparing the steam chests for final inspection and the fitting of new valve liners.
Reaming and countersinking some of the spring bracket rivet holes was completed this week, now that the reamer we needed had been sourced. All the spring bracket holes are now ready for riveting.
Work resumed at the dragbox this week. It took weeks of effort to manually ream out the dragbox holes but the uneven surface around the holes is unsuitable for tightening a nut onto when we fit new bolts. It was decided that the holes needed spotfacing. This is cutting a flat surface around the bolt holes with a special cutter. After discussing this with one of the volunteer Engineering Team members last week he brought in a spot face cutter mounted on a spindle that he had made in his home workshop. A close fitting bush is fitted in the hole and the spindle runs in it keeping the cutter square to the hole. It was used this week and three spotfaces were cut. It's another slow process due to the space only allowing a small electric drill to be used.
Painting this week continued on the frames and black gloss has been put on the mechanical lubricator bracket ready for the lubricators to be refitted. Further prep work for painting around the front right footplating managed to loosen a few more footplate rivets. The burning gear was out this week and a few more loose fasteners were removed that were identified for replacement. The holes are now being prepped for new rivets.
The air pump cleaning was declared complete this week. We will now begin to dismantle the pump and begin its repair.
The last of the hornstays were removed for inspection this week. The leading right was removed last week but needed more work so was removed again this week. When the leading left was removed that also needed a considerable amount of tidying up. Both the leading hornstays seem to have had a very hard life so it has been decided that both should be removed and will receive further repairs.
22 January 2017
The main activity of the week is the continued painting of the frames with the inside of the frame plates receiving their first coats of primer. Paint is also now being applied to the underneath of the footplating and angles. In front of the painters there has been plenty of needle gunning and cleaning to be done. The last couple of footplating fractures were welded up this week. To the side of the frames the air pump is being cleaned inside and out.
The buffers were taken apart this week by carefully removing material from the inner buffer to allow its removal from the outer housing. With these parts separated they were then cleaned out of the thick accumulations of grime that had collected and they will now be reconditioned before reassembly. The buffers have backplates that fasten to the back of the buffer housings. The fixing holes were cleaned out and re-tapped. Broken studs in the buffer housings will require removal to allow the backplates to be refitted.
The frame plate to the rear of the left hand cylinder casting, that was hidden behind the left hand leading sandbox, was "di-penned" this week. After detailed inspection is was declared defect free and was then primed. All the outside of the mainframes up to the cylinder castings have now been primed. Further areas subject to flaw detection this week included the brake hanger brackets. These were given a final clean and the test fluids applied. No faults were found.
Reaming of the spring bracket holes where loose rivets were removed from the frames has been carried out intermittently over the last few weeks. It has been difficult to obtain an acceptable finish to these holes as they have been welded up in the past and no matter how hard we try the adjustable reamers leave "chatter" marks due to the uneven hardness in the holes. This week Malcolm Bateman used the mag-drill with machine reamers and a number of holes were finished ready for new rivets. We prefer to use an adjustable reamer as it removes less material than having to increase a hole size up to a fixed size reamer. The worn fitted bolts that secured the frame stretcher that holds the vacuum lock were replaced this week. New bolts were finished machined and have now been fitted.
The horn cutout of the trailing right hand at one of the top corners was found to be quite roughly cut. This is historical, however this is also a highly stressed area on the frames so to remove any potential crack initiators the area was carefully smoothed.
The steam chests, where the valve liners were removed, have been cleaned of carbon deposits. These areas were previously made inaccessible by the liners. Careful cleaning is required to ensure a good fit from the new liners, this work will continue. Measurements have been taken and it appears these confirm no change from last time the liners were replaced. Quotations are now being sought for the supply and fitting of new liners.
The removal of the middle cylinder cover studs continued this week. A drilling jig has been constructed to accurately drill out the remaining studs. The jig worked exactly as planned and we were able to drill out a stud to tapping size and to remove the remnants with the point of a scriber.
The hornstay removal and inspection was continued this week with the leading right hand. This hornstay seems to have received quite a battering over the years so a considerable amount of time had to be spent in cleaning up the burrs from its bottom outside edge. The burrs were ground off then the grinding marks were removed to give a smooth finish. It was then visually inspected and decided that it would require further work, however so as not to leave the frames unsupported the hornstay was refitted and it will be revisited next week.
15 January 2017
Battle recommenced on the removal of the middle cylinder cover studs. Though slow, we are making progress with, by the end of the week, one full stud left, however there are a small number that have broken and will require drilling out. Of course the broken ones are the most inaccessible ones. The Engineering Team is now working on the design of a jig to ensure accurate drilling of the broken studs, as we cannot risk any damage to the cylinder casting by wayward drilling.
We haven't worked on the bogie for some time as the Engineering Team has been fully occupied on the the loco frames. In the meantime the bogie had been moved to allow Rocket's boiler to be placed where it could be dismantled for overhaul. Where the bogie was moved to was unsuitable for further work. However, with the removal of some of the racking from the workshop we identified an area where we could put the bogie and work on it. With the agreement of the NRM Workshop Manager, a trio of Engineering Team Leaders skillfully moved the bogie frames to where we have plenty of room to recommence work.
Painting has continued this week with primer being applied to the main frame plates for the first time this overhaul. In front of the painters other team members have been attending to any prep work prior to painting. With the removal of the buffers this has required descaling and cleaning around the buffer housings and the bufferbeam itself.
The front buffers carry some damage from an historical heavy shunt. They are fully serviceable but can't be fully dismantled for cleaning and inspection. So this week the repair of the buffers and careful dismantling began. Whilst at the bufferbeam the removal of the left hand buffer has allowed the replacement of a loose rivet identified during the frame survey. This was replaced by the Riveting Team on Friday. At the same time a rivet was replaced on the bufferbeam to mainframe bracket behind the same buffer.
At the dragbox, reaming was completed this week. Well done to everybody who has taken a turn on this job. A magnificent result has been obtained all by hand, in an inaccessible location. We also used the magnetic clamp drill for reaming this week to clean up some holes that were very close to available machine reamers that the NRM loaned us. The fitted bolts for the reversing shaft vacuum clutch were roughed out on Saturday but require final machining and fitting.
Next to the frames, cleaning of the air pump and preparing it for overhaul continued with the strainers and cladding being removed and cleaned.
The inspection and assessment of the hornstays continued this week with the centre/driving hornstays. Both were dye-penetrant inspected and were found to be flaw free and were then refitted to the engine. Further inspection work this week was carried out in the steam chests where the valve liners have been removed. This critical area requires careful assessment as the new liners have to be a good fit. After assessment it will be decided if any reconditioning of the casting is required.
8 January 2017
The dragbox reaming continued this week. This has turned in to a time consuming job as there are a number to do and they are deep holes. I must thank the patience of those taking their turn with this job. On Thursday I examined the results so far and I think the end is in sight.
Painting continued this week with primer now being put on to the forward sections of the inner and outer Cartazzi frames. Elsewhere the Painting Team has applied further coats to the large "+" stretcher and continued on the footplating. The footplating has also seen the attention of the welder. As previously reported the footplating has cracked in service and is being welded up. The right hand side is now complete and some prep work has been done to the left side.
The footplating has also seen the replacement of the loose rivets around the brackets where the splashers are secured. The loose rivets were identified during the frame survey and were then removed. On Friday the Riveting Team replaced the rivets on the long angles that fasten the outside of the leading splashers to the footplating. The frame/splasher brackets were also re-riveted, where we could access them. There are a number that are inaccessible with the set up we have but we have a plan.
The valve liners were removed before Christmas and the steam chests now need cleaning out and preparing so that we can take measurements in preparation for ordering the replacements. The right hand steam chest has now been cleaned out. Later in the week cleaning of the air pump continued, one of the most difficult items to get clean due to its complicated shape.
The Engineering Team is now removing the hornstays to assess their fit and to examine them for damage and cracks. The trailing set were removed and after cleaning were "di-penned". After detailed examination they were declared free from defects. They were then refitted. Their fit is good so they should not require any work, though it has been decided to fit new securing bolts at this overhaul.
On Saturday we had a productive "007 Gang" (Junior Volunteers) working day. Both buffers were removed and dismantled. A start was made on cleaning the components and the buffer housings on the loco.