News and Views from the
TYNESIDE SOCIETY of MODEL and EXPERIMENTAL ENGINEERS
The much-anticipated relaxation of CV-19 restrictions on June 21st didn’t happen but, thanks to a continuing run of fine weather, life outdoors carried on with plenty of activity on and off the tracks. The next “big” date is July 19th, but I’m not holding my breath …
AGM (Linda Nicholls)
As we are coming out of lockdown, several members are getting back to running their locomotives. Please remember to check your boiler paperwork to ensure it is still in date.
If you need a boiler test please contact one of the Boiler Inspectors beforehand to agree a date and time. Do not just turn up expecting them to drop what they are doing to test your boiler. If you do not have the contact details please contact the Secretary (firstname.lastname@example.org or 07761960788) and she will book it for you.
There are four different types of examination, these are relevant to all boilers (16mm to 7 ¼inch).The boiler will be examined for leaks, distortion or damage to ensure it is safe to be used under pressure
A Shell Test – This is a one-off test carried out on all new boilers to twice working pressure. If you have purchased a professionally-built boiler it should come with a certificate. This will need to be presented to the Boiler Inspector and there will be no need for them to do another shell test unless you have modified the boiler.
If you built the boiler yourself the boiler must not have any fittings in place and all bushes plugged. One bush is used to connect the test gear which requires ¼ BSP or 3/8”x 26tpi male threads. While the Inspectors have some adapters, you should check with them before the test.
A Written Scheme of Examination – This is completed for new boilers or boilers of purchased engines new to the Society. A copy of the Written Scheme is sent to the Southern Federation of Model Engineers as part of the Club’s insurance scheme.
A Hydraulic Test – Required every 4 years, (for steel boilers every 2 years after the test at 4 years) the boiler is filled with water and pressurised to 1 ½ times working pressure with all fittings in place except the safety valve/s. One bush is used to connect the test gear which requires ¼ BSP or 3/8”x 26tpi male threads. While the Inspectors have some adapters, you should check with them before the test.
The pressure gauge can be left in place providing the scale is sufficient to take the test pressure. Otherwise the pressure gauge has to be removed to be hydraulically calibrated and the siphon blanked off.
A Steam Test – A steam test certificate is valid for up to 14 months at the Inspector’s discretion, (the Inspector will complete the retest date on the certificate depending on a number of circumstances, e.g. if the hydraulic test runs out before the steam test).
The pressure gauge must be removed and presented for separate hydraulic testing/calibrating before the steam test.
There must be at least two means of adding water to the boiler successfully demonstrated as part of the test.
The safety valve/s must open at the working pressure and must prevent the boiler pressure exceeding the working pressure plus 10% with the blower fully open and a full fire burning.
These are guidelines so please feel free to ask the Inspector for more information.
If you are planning to build a new boiler please talk to an Inspector before starting to ensure that it will meet current standards.
LPG Tanks A reminder that gas tanks need a safety check at not greater than four yearly intervals.
Your Boiler Inspectors are …
Ian Spencer ( 0191 284 3438 )
Stu Davidson ( 0191 253 1802 mob 0794 931 3367 email email@example.com )
Brian Nicholls ( 0167 081 6072 mob 0752 230 0752 email firstname.lastname@example.org )
Scrap Drive (Steve Lowe)
An occasional source of Club funding is the sale of scrap metals, and a trip to the Scrap Yard is planned for the end of July. Please bring along any non-ferrous scrap you may have before then.
Junior Engineer Sam Yeeles continues to produce excellent line-side photographs which make it to publication.
His latest, appearing in the June issue of Heritage Railway magazine, is a beautifully framed and perfectly timed portrait of LMS Jubilee No.45690 “Leander” storming out of the northern portal of Blea Moor Tunnel on the S&C heading for Carlisle on June 1st 2021
Members Musings …
Bending angles is always a bit of a challenge to get right and plate work is not my strong suit. So, I like to get technology to give me a hand. The Berkshire tender has four curved angles that fit to the coal boards. So, my plan was to CNC them out on my mill.
Unfortunately, it’s been over six months since I switched it on. In that time the free offering of Fusion 360 had been crippled for the hobbyist. I also wanted to try a different machine strategy by using tabs on the components so there was no second opp machining. So, what could possibly go wrong ?
The angles were 1/16” thick and I intended to machine the tabs to .375” x 0.03” thick. I planned to machine a handed pair from a 4” square block.
The basic machine strategy was two roughing passes using a 10mm roughing end mill and then a clean-up and tab pass using a 6mm end mill. The four-inch block was machined on the bottom then once in the CNC mill, I faced the top off to size. Crippled Fusion means that all movement is at the tool feed rate, in this case 7”/m and 10”/m for the milling so there are no rapid feeds to linking moves. So, for instance, in the above illustration the yellow diagonal linking move was at 10”/m instead of 60. This adds considerably to the machining time but as it’s CNC I can do something else and I’m not paying a £400 licence fee for something I only use once in a blue moon these days.
The first pair, shown above, was a qualified success, however the floor tended to deform due to its width 4” and thickness 1/16” when it came to cutting the tabs. Not shown here but when I came to
centre drill the holes, I got the linking safe height wrong and snapped the drill and damaged the web on the angle so badly it was a scrapper.
So, I needed to do a one off which cut far better, probably due to being a lot smaller and not deforming as much when cutting the tabs. Once all four had been finagled out of the parent metal they just needed a rub with a file and were ready to fit to the tender.
The angles were then temporarily clamped for match drilling, then the coal boards and angles were celco’d together for final drilling and riveting.
Once the coal boards are riveted that will be the riveting completed. There is still a fair bit of detail work to do. But with a fair wind I hope I can bring the tender to the Club this year and get a tow round to see if the Buckeye trucks take the curves.
How Staffa got its Hexagonal Columns (A Cautionary Tale)
Shortly after the Earth had formed, the ground was still warm under (non-existent) foot. Floating in the primordial soup was a lone jellyfish. Sex was not yet invented and this creature lacked drive, ambition or empathy. God, realising that a considerable number of versions of Earth were forming, decided that a uniform plan was desirable.
He designed an Earth of blue seas, green pastures and intriguingly shaped continents. Observing the protoplasmic nonentity in the soup he realised that in a few aeons this could develop intelligence, insight, and communal kindness.
Only one difficulty presented itself. The elements of the Earth, of landscape, fauna, seascape and mountain were all so beautifully coordinated that design would be unrecognised. God reflected for several eons. Perhaps he should design something so original that intelligent design would be obvious. A signature range of mountains lacked authenticity; pyramids were rather triangular though the idea of a trinity was attractive. Finally the hexagon was selected. An island composed of hexagonal columns combined mathematical elegance with aesthetic sophistication.
God, like many subsequent designers, left the actual execution to someone else – Basalt, a fiery being who formed much of the Earth. Although later petrified, this incandescent entity had a good grasp of practical volcanism. Basalt set to with a will. Meanwhile, God redistributed the dark matter.
Later, approaching from the west, God observed a perfectly formed island with black hexagonal columns rising in a delightfully symmetrical manner.
Rounding the southern margin, a cave issued ethereal sounds as waves echoed through the cavity. The sounds were later appropriated by an itinerant Viennese composer. God felt a glow of satisfaction which brought forth a nova and twin black holes.
Rounding the southern extremity of the island, God was appalled that vertical symmetry had been replaced by twisting spirals of frankly irregular hexagons, forming arches and spurs never envisaged in the Almighty’s plan.
He summoned the perpetrator of this abomination. Basalt, more engineer than mathematician, had initially used the hexagon of equal sides. It gradually occurred to him that hexagons could pack just as efficiently with variable lengths to the sides. He thought that God would applaud this discovery. He was frankly distressed by the Creator’s evident lack of appreciation. Retiring hurt, the resulting tectonic movements created the Andes.
God pondered. If this could arise in designing a simple island, the problems of designing a complete biosphere were enormous. He gazed into the Soup searching for the protoplasmic nonentity. Instead, streamlined fish with iridescent scales flashed about, some of which had begun to crawl onto dry land. God realised that the forces of nature had helped the jellyfish achieve the missing drive, ambition and sex.
The solution was to let nature take its course. He foresaw the drawbacks, the evolution of politicians, conceptual artists, and hedge fund managers. With the example of Staffa in front of him such horrors would have to be tolerated.
“Bother Intelligent Design”, said the Lord”, “Let’s see what Nature can do”. Brightening, he realised that he had ordained the evolution of J.S.Bach.
It’s said that variety is the spice of life, and you certainly have that in this issue. Thanks as ever to the contributors who made it possible. The Editorial Cupboard is, again, bare. You all know how to fix that …
- Newsletter Editor – Mike Maguire – email@example.com
- Club Secretary – Linda Nicholls – firstname.lastname@example.org – 01 670 816072
- Website – www.tsmee.co.uk
- Webmaster – John Rowley – email@example.com
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