I now had two options; one was to make eight new liners, the other to bore the original liners out again fractionally bigger, the latter making it necessary for me to make another twenty-four valve rings, plus some extras for those that I might break! I therefore opted to make new liners and in doing so move the exhaust ports to the extreme end of the liners so all three valve rings would always make an effective seal whatever the position the valve was in the steam chest.
The extractor ready to remove the first of eight steam chests.
I now also decided to dispense with the reamer and cut out the ports last. I have a 1" roller bearing, that I think came out of a Class 47 diesel axle box when I was at work, and it now came in very useful as a gauge during the boring out of the liners. I allowed the tool to run out several times in the final boring until the roller went through like silk. When I removed the liner from the lathe, with a drop of oil on the roller bearing it would hold itself in the liner by the vacuum in an upright position if I held my hand over one end. So I was now quite happy that the liners would be alright when refitted. Only then were the ports cut out.
The first two liners were then fitted to the cylinder block and the valve inserted into the steam chest. With the air supply now turned on the valve made an excellent seal, despite the fact that they had not yet bedded in. Moving the valve from one end of the steam chest to the other also produced a significant, and welcomed, exhaust beat up the chimney. What a relief that was! Although, I now had the difficult task of removing the inside cylinder block from the chassis to change the liners on that.
I did feel hopeful that the inside cylinder casting was likely to come out of the frames if I first removed the front buffer beam and associated parts. However, further disappointment was to ensue, as the cylinder block just would not come out, the inner steam pipe flange fouled the bottom of the smokebox by just about an eighth of an inch. Regrettably, the smokebox now had to come off; this obviously was to do little for my many hours of meticulous painting, or my blood pressure!
This was indeed to be a drawn-out task, but there really was no alternative. I wrapped a nylon strap around the leading end of the boiler barrel and attached it to the hoist. Just taking the weight of the boiler on the strap I was able to start dismantling the smokebox connections. Fortunately, this kept any damage to the boiler paintwork to a minimum.
The new liners showing the 1" roller bearing used as a gauge. The distance between the steam port and exhaust passage needs to be the width of the valve head. Original liner on the right rear of picture.
After many more hours’ labour, the work was eventually completed on the left-hand outside cylinder also. I now had the valve timing to reset again, and this in itself was an enigma. With a four-cylinder engine you never can quite tell whether one engine is retarding the other. I had in fact discovered this earlier, the engine would actually run with the timing well out of setting on one of the engines, as the other three cylinders tended to carry the sequence over.
I now decided to set each pair of engines individually on compressed air, starting with the inside cylinders piped up only. When satisfied that these two valve settings were right, I piped up the two outside cylinders and set these two valves independently also. This meant quite a lot of time spent making adaptors for the air-lines, but this time, I felt, was well spent.
Finally, the whole reassembly work was done and I was then able to run the engine on air again with all four cylinders working. Thankfully, I now only had four crisp exhaust beats!
The appalling December weather was a further frustration to a second test run. However, when the snow cleared, undaunted, the lads from the society were very eager for another run. Although it was still bitterly cold and I questioned my own wisdom at venturing out in such conditions at my age. Nevertheless, I was able to retire to the club house for the occasional warm whilst James Gorton did the steaming up. There was a good side to the weather conditions; it did discourage too many onlookers!
James Gorton steams up, very closely scrutinised by Trevor Shortland. The bitter cold morning kept away too many onlookers.
With steam raised and everything checked, I ran a complete circuit of the track and the valves were now fine. In fact, she was now like our ‘Black Five’; you could drive her with the regulator wide open and just alter the valve cut-off to suit the gradient. Everything else also seemed to be functioning well, the injectors picked up every time by just opening the water wide and turning on the steam. She made steam extremely freely, the fact it was unnecessary to close the firehole doors an indication that perhaps the blast pipe nozzles needed opening out to soften the draught. But there again, I was yet very much on a learning curve. I have also since agonised over whether the original valve design may have perhaps been quite satisfactory and the problem was solely down to the steam chest liners!
Almost inevitably, there had to be a downside, and with a circuit almost complete the front bogie derailed, and regretfully, this was not a one-off situation. At some point earlier I had attached some scales to my hoist and just to get the smokebox end of the engine off the ground took 209lbs, without any water in the boiler. Whilst the younger members were able to get the engine back on the rails, I was very much afraid of someone suffering a back injury. So yet again, I was to endure utter frustration and it was back to the proverbial drawing board for me.
At first I felt that the bogie problem was just due to weight distribution, however, I was again under a misapprehension. The curves at Wythall have a 50ft radius and I guess that when we first towed the engine round with our petrol locomotive, the towing action must have kept my engine in line with the track. The whole purpose of me building this engine was for it to run at the Wythall Museum, it was going to be a sad day for me if I couldn’t eventually get it to run there reliably.
Foremost, my decision was to put more pressure on the bogie by making new spherical bogie-to-chassis bearings by increasing the size of both the ball and the cup slightly to give another 1/8" downward pressure.
After fitting these, with the weight of the engine back on the bogie, I noticed that the rear bogie axleboxes had lifted in the horns rather more than the front. This required correction, yet I really did not want to spoil the look of the external coil springs on the front bogie axlebox by fitting softer springs. I eventually got around this problem by carefully grinding out the centre bore of the springs. This was very much trial and error until finally the front axleboxes equalled the back by the same amount that they had risen in the horns.
Grinding out the inside of the bogie springs.
To do the grinding down of the inside of the springs I came up with a quick solution, which I feel is quite worth mentioning, as it will no doubt come in very handy in future. Yet it only took about ten minutes to make.
I took a 6" piece of box section steel, drilled a hole the clearance size of the lathe tool post bolt, and cut away a section at opposite end. In the section that I had left opposite the bolt hole, I then drilled a ¾" hole with the drill held in the lathe three-jaw chuck. By doing this, I was then able to mount my Draper mini drill in the tool post as in the photograph. With the mini drill and lathe running in opposite directions at high speed it took but a few minutes to grind the inside of the springs to a thinner section, whilst taking care not to overheat them and perhaps ruin the tempering. It is obviously also a good idea to cover the lathe bed to avoid grinding dust adding quickly to wear of the lathe. Perhaps this tool post grinder could be used in the future for producing a good finish on small taper reamers and the like? Or even used for truing up worn lathe centres?
Again trying to cover all eventualities, I did further tests on the flexibility of the bogie and discovered that the bogie frame itself was held pretty rigidly on the main centre pin by the large retaining nut underneath. As it was, any undulations in the track would have to be mostly taken up solely by the axlebox springs. I therefore now decided to enlarge the centre pin hole at the bottom of the bogie chassis castin
g where the ½" x 26 screw thread comes through to give much greater clearance for the bottom of centre pin. Doing this then allowed the bogie frame itself to roll on the centre pin in an up-and-down movement.
Looking even further for every possibility as to why the bogie derailed, I also found that there needed to be greater clearance for the engine to tender coupling bars. The main coupling particularly, did not allow sufficient flexibility, and this was allowing the weight of the driver on the tender to be transmitted to the engine rear drag beam. Downward pressure here could have a tendency to lift the weight off the front of the engine. Particularly, as excess of fifteen stones in the weight of some potential drivers is likely to be quite common. The three coupling bars were therefore all slimmed down quite a lot, obviously without compromising their strength to any degree, but they really do need to be quite sloppy. The intermediate spring buffers will still keep the distance between engine and tender.
Feeling that I had now covered every likely reason for the bogie to become derailed, a third test run was arranged. Sad to say that this again led to further disillusionment, as the same problem was to manifest itself. This utter frustration now did very little for my self-esteem; I was once again pretty devastated.
Many heads are better than one and we were all now of the opinion that the problem was almost certain to be due to the lack of flexibility between the engine and tender. We noticed that on the curves, whilst the inside intermediate buffer fitted to the tender was fully compressed, the opposite side subsidiary coupling bar was very tight and had a tendency to try to keep the engine and tender in line with one another.
Back in the workshop I made new secondary coupling bars slightly longer than the originals. Again, I did not want to spoil the aesthetics of the engine by making the gap between the engine and tender over scale. To achieve an even greater angle of flexibility on the curves I also slimmed down the intermediate buffer heads and made certain that they fully depressed against the tender drag beam.
Subsequent running tests then became quite heartening; even so, the occasional bogie derailment was still an irritation and it would now have been quite easy for me to blame the track. One derailment is one too many, particularly if passenger hauling on the museum open days. This would mean important revenue loss; looks unprofessional and children soon become restless and tend to fidget if things are not kept moving. However, in sheer desperation now I decided to re-profile the bogie wheel tyres. Reducing the near to 3-degree angle, or 2 degrees 52 minutes 51 seconds as on the drawing, to just one degree. This gives a deeper flange and I also reduced the diameter of the radius between the flange and the tyre tread.
A further setback then occurred with the tender brake, which I subsequently found had to have the adjustment very loose whenever heavy drivers occupied the seat. As the axleboxes rose in the horns, the brake blocks had a tendency to go tight on the wheels. This made setting up the working vacuum brake adjustment difficult. I learned in full-size practice that vacuum brakes are only efficient when closely adjusted to the wheel. In the old days, when we worked heavy freight trains over the Black Country gradients with small tank engines, drivers would often have the brakes adjusted on the same engine more than once in the same week. With my engine it was impossible to achieve proper adjustment and I therefore referred to the drawings again. My opinion was that the brake hanger brackets were set too high, as the brake blocks appear to be above the centre line of the wheels. I therefore decided to drop the brake hangers by 9/16" whereby the brake adjustment is now much better. When heavy drivers now take charge also, the brake blocks come off the wheels rather than bind on.
The tender axleboxes machined to take the self-aligning bearings.
Essential track work at Wythall delayed the next test run and it was only the week before Easter that steaming was possible. I sincerely hoped that this would prove satisfactory so that the first public passenger hauling could take place during the holiday weekend.
My heart sank when on the first circuit the engine bogie derailed yet again. To my relief this did turn out to be a problem with the track and some temporary juggling allowed me to make several runs round without any problems. Several club members also had a drive round successfully, even though the lubricator was now proving a little too generous.
A few passenger vehicles were then attached and with a moderate load she performed reasonably well, although I did feel a bit disappointed with the power output. She would stall on the rise if the pressure fell below 60 p.s.i. when our Hunslet would plod happily on with 40 p.s.i. Nevertheless, the spring sunshine brought some early visitors to the museum who soon began to show an interest. The train was also soon full and we were glad to give these free rides for testing purposes. With some regret, whilst pulling hard on the curves, the leading tender wheels again became prone to derailment. This was a mystery in itself, but it was also really disappointing that the engine failed to make a start in places where our ‘Black Five’ would easily cope. The failure to start the train was therefore not entirely due to the larger size of the ‘King’ driving wheels. With a slight nudge the engine would be quickly away and go into violent wheel slip if you were not careful, but then she just would not go from a standing start whilst on the curves. I then suspected that further adjustment of the valves could now also a probability, a problem that I had to face with some trepidation.
I slept on the dilemma of the tender derailing for several days, as yet again, I just did not know what I could do next. Could it be that the tender binding on the track was also enough to stop the engine starting on the curves? So yet again, I decided to take the bull by the horns and not only re-profile the tender wheels, as I had done on the engine bogie, but fit self-aligning bearings to the tender axleboxes. In addition, I decided to give extra clearance with regard to the side play on tender axleboxes.
The bearing supplier that I had always used in the past wasn’t at all helpful and wanted to charge me £16 plus vat for each bearing, that’s if he could get any. Browsing the internet, I found that any amount of suppliers only put a code number for every type and size of bearing on their website, which does make it difficult for any amateur to find what they want by size. You cannot tell the size of a bearing from a photograph! However, I eventually found one of the very few websites that displayed the sizes along with the bearing code. I telephoned ‘Lost Your Bearings Co Ltd’ and got excellent service. Despite the Easter Holiday, the Royal Wedding, and May Bank Holiday coming together, the bearings were in my possession in three days, this at less than half the price of my first inquiry.
The job went well, the bearings were soon fitted and also a sixteenth of an inch extra sideways movement was machined into the axlebox slides. When the wheels were spun they rotated as you would expect a cycle wheel to turn, I just hoped that they still ran so freely with heavyweight drivers sat on the tender! I also did re-profile the tender wheels, as I had previously done with front bogie.
Although the engine had been reluctant at times to start on the curves, I was equally hesitant to make any adjustments to the valve setting. I had previously set the inside and outside engine valve timing independently of each other to be sure that one engine did not retard the other. I did however eventually decide to take out each cylinder pressure relief valve so that I could listen to the exact point where steam would enter the cylinder once I had pressurised the boiler with compressed air. Doing this, I did make very minor adjustments to the settings. Whilst making these adjustments to the valves I became aware that the left-hand front outside cylinder cover was leaking slightly and therefore decided to remake the joint. With the cylinder cover off, I made a casual check on the piston head retaining nut and was pretty disappointed to find that it was slack. As I have seen other people’s engines throw a piston head in the past, together with when I had earlier seen the design stipulated on the ‘King’ drawings, without a lock nut, I was indeed very apprehensive. Whilst a small engine throwing a piston head would probably do little but lo
ck the wheels, an engine of this scale with the same problem could be catastrophic. Nevertheless, against my better judgement, I did make the parts as drawn, but did decide to ‘Loctite’ the retaining nuts in place. This had obviously been inadequate and another method of securing the piston heads was now called for.
The double row self-aligning bearings.
Although the engine had been reluctant at times to start on the curves, I was equally hesitant to make any adjustments to the valve setting. I had previously set the inside and outside engine valve timing independently of each other to be sure that one engine did not retard the other. I did however eventually decide to take out each cylinder pressure relief valve so that I could listen to the exact point where steam would enter the cylinder once I had pressurised the boiler with compressed air. Doing this, I did make very minor adjustments to the settings. Whilst making these adjustments to the valves I became aware that the left-hand front outside cylinder cover was leaking slightly and therefore decided to remake the joint. With the cylinder cover off, I made a casual check on the piston head retaining nut and was pretty disappointed to find that it was slack. As I have seen other people’s engines throw a piston head in the past, together with when I had earlier seen the design stipulated on the ‘King’ drawings, without a lock nut, I was indeed very apprehensive. Whilst a small engine throwing a piston head would probably do little but lock the wheels, an engine of this scale with the same problem could be catastrophic. Nevertheless, against my better judgement, I did make the parts as drawn, but did decide to ‘Loctite’ the retaining nuts in place. This had obviously been inadequate and another method of securing the piston heads was now called for.
The Mettle for Metal Page 9