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Member postings for Bob Youldon

Here is a list of all the postings Bob Youldon has made in our forums. Click on a thread name to jump to the thread.

Thread: Dick Simmonds Loco Centre Erith
09/09/2016 14:42:52

Good afternoon Colin,

I knew Fred Stone quite well, and as people have said, a bit of a character. The shop always reminded me of being a greengrocers/ nursery in a previous existence. Previously the model engineering business was owned by Dick Simmonds, who used to advertise as the original back yard foundry. There was no water laid on, so no facilities etc; Fred always collected rain water in a big tank out the back. Fred didn't live too far away so he would often pop home, you could never find him during Saturday afternoons, he would always like to watch the wrestling on the television, home we'd all go and his wife, May, would ply us with tea and cakes!

I don't think the shop ever got cleaned, at high level all around the shop were shelves on which there were piles of Model Engineers dating from the year dot, vast cob webs and some enormous spiders! at low level there were wooden bunkers filled with castings of every description here again there were some seriously big spiders lurking in some of the cylinder castings. The door stop was a 71/4" gauge cylinder casting.

Fred's boiler making skills were first class most of which was carried out at the in a small workshop at the rear.

Someone mentioned Fred's wooden leg, he would frighten the youngsters as he hammered in drawing pins to hold his socks up!

Fred built a number of fine locomotives, I seem to remember a nice 5" gauge GNR Atlantic and I think he built a 71/4" LNER mogul amongst others.

Great days.


Bob Youldon

Thread: Another Speedy valve gear design?
08/09/2016 19:39:06

Good evening all,

Bill Perrett was an excellent engineer and a leading light in the Southampton Model Engineers, his locomotive wasn't a LBSC speedy, it may have started out based on one but Bill built it much more like the full sized machine and to do a job of work and that included a different valve gear design I think in it's time Bill wore out more than one boiler, several sets of wheels and won IMLEC on more than one occasion. His locomotive appeared on the cover of ME many years ago and his comprehensive design for passenger cars was published in ME some time ago.


Bob Youldon

Thread: Petrol tap thread
29/08/2016 21:15:28

Whato Baz,

Try 1/8" BSP



Thread: Whats the least expensive 7 1/4 build?
15/08/2016 20:58:31

Good evening Fizzy,

I must be one of the most tight fisted model engineers around, the only castings I'll shell out for these days are wheel castings. Some of the prices quoted today for cylinders are astronomical and frankly I'll provide my own blow holes! There isn't much on the stock designs that cannot be fabricated, in fact some of the cast items offered are very poor; cylinders are a reasonably easy to replicate, see the current series in ME by Terrence Holland, even the new build Brighton Atlantic at the Bluebell Railway uses built up fabricated cylinders. By careful choice of prototype, say the little L&Y 0-4-0 pug, even the wheels can be fabricated. If its a stock design you'd prefer then there are a number that'll lend themselves to fabrication with perhaps the only investment being wheel castings.



Thread: GWR Number Plates
12/08/2016 20:42:28

Hello Mike,

The chap you were thinking about was: - I was vert impressed when I saw the plates etc at an exhibition a few years ago.



Thread: Loco built in 9 months
17/07/2016 09:03:46

Good morning all,

A very good friend built his first locomotive, a 5" gauge Butch in just under twelve months followed up with a 5" gauge Springbok, again in twelve months; he puts me to shame. The quickest locomotive I've ever built was a Don Young designed 3.5" gauge 4F which I built in just under sixteen months, incidentally the only bought in items being the castings for the wheels, cylinders and a pressure gauge.

Old LBSC would quote his "two hour hand pump" It takes me that long to find the materials these days!



Thread: How do I make a steam operated valve?
06/07/2016 20:33:35

Hello Fizzy,

For lapping I'd suggest a product called Timesaver, take a look at I've never had a problem using it, it does what it says on the tin! I also keep a tin of Ajax scouring powder, always useful in the workshop. It always helps if you use dissimilar materials for each face, e.g.. phosphor bronze or monel disc on a gunmetal face; yet another idea, a chap on another forum is insetting the disc faces with a PTFE insert,


Bob Youldon

Thread: Everlasting Blow Down Valve ?
14/06/2016 12:31:57

Good afternoon Stewart,

I didn't think I was going mad, in the 1954 edition of "The Live Steam Book" pages 205 - 209 contain drawings and a description of the construction of an "Everlasting" blowdown valve; whilst it is for a 3/4" scale locomotive it could easily be enlarged to suit a 5" gauge locomotive.

A very good description and drawings for a similar valve for a 11/2" scale locomotive appear at

Incidentally, I have an early copy of Shops, Shed and Road in which someone has indicated it was published in 1929 and it would appear to have been J N Maskelyne's own copy as he has signed the fly leaf; on the first page there is a note and poem by LBSC, it's signed Curly, Purly Oaks locomotive works, August 1949, also there's a rubbing of his LBSCR cap badge and a rubbing of the numberplate of his little 31/2" gauge single Grosvenor. For the record the "Everlasting" blowdown valve doesn't appear in that edition.


Bob Youldon

13/06/2016 19:43:47

Hello Stewart,

The" Everlasting blowdown valve" as specified by Don Young is a larger version of that described by LBSC in his Live Steam book. The valves were excellent as the operation was by simply a lever and by design the valve was kept on it's face by boiler pressure until operated. In this country Riddles fitted his standard designs with the Everlasting blowdown valve, no doubt made here under licence, the valve being positioned low down on the throatplate and the valve operated by a pull handle. I think Doug Hewson in both of his 5" gauge BR standards, the standard 4 4-6-0 and the standard 4 tank, described the construction and installation of an everlasting type blowdown valve.

I would advise incorporating a similar valve much as Don suggested.


Bob Youldon

Thread: Boiler Marking/serial number
06/06/2016 23:52:54

Hello Julian,

Re, Funny how many boiler inspectors don't have a set of stamps with them for the first test! Boiler inspectors should not have any involvement other than to examine the construction of the boiler, witness any testing and record that process and the inspectors findings. The stamping of any identifying marks must remain the responability of the manufacturer or builder.

Ideally in the case of non commercially constructed boilers the serial number of the written scheme document, that being the commencement of an audit trail, should be incorporated in the stamped identification together with the designed maximum working pressure; personally I like to stamp the backplate before fitting to the boiler, the idea of stamping the boiler after completion in it's relatively soft state worries me.

Thread: Crop Circles - poor surface when milling
05/06/2016 16:28:28

Hi Iain,

I still think a large fly cutter at speed and a fairly slow feed rate will give you a surface finish like the finish from a surface grinder, but you must ensure everything is spot on, no slack anywhere. I did a pair of Rover V8 cylinder heads exactly that way on my Dore Westbury several years ago and they were spot on. I will often use a fly cutter, far cheaper than end and face mills etc.


Bob Youldon

Thread: Experience
01/06/2016 16:38:51

Hi all,

When in doubt give it a clout was a local saying here in wet and windy Sussex.


Bob Y

Thread: injector problems
11/05/2016 21:00:11

Good evening Ron,

May I be as bold to suggest you get yourself a copy of Miniature Injectors Inside and Out by D A G Brown; read it from cover to cover and then again, as it will provide the comprehensive answers you're seeking.


Bob Youldon

Thread: Bad day & a pigs ear with a reamer
16/04/2016 20:55:22

Hello Sam,

I'd rebore the casting, but use the stoutest boring bar you've got with a nice round faced cutting edge, take out a couple thou at a time until you reach almost finished bore size, then don't alter anything, go up and down the bore on the same topslide setting several times using the self act and you'll have a nicely finished bore, It's not too important if it's up or down a couple of thou, it's more important it's parallel.

Best of luck,

Bob Youldon

Thread: CE Marking ( again)
08/04/2016 17:26:03

Good afternoon Brian,were

I would as Fizzy has suggested, your first approach should be to your club boiler inspectors. It is an interesting question as the original paperwork is the start of any audit trail. The revised test procedures were promulgated in 2012 and the paperwork differs considerably to that of previous test regimes; as someone has already mentioned there was no statutory requirement on the part of Polly to retain copies of the paperwork, certainly beyond seven years; further I think the Polly who may have constructed the boiler may not be the same Polly Engineering we know today, the original company/supplier being taken over/bought by the present owners. Paperwork can and will get lost or destroyed, It won't be the last time I've seen a grate dropped into a tool box at the end of a days run, the test certificates being almost totally destroyed. So there has to be a starting point and that's your boiler testers, tease out the situation with them, they can always take council with the Northern Association and come to a decision as to the way forward.


Bob Youldon

Thread: Excellent service
02/04/2016 15:39:32

Good afternoon all,

I must also congratulate Macc model engineering on their speedy service; I ordered on Wednesday at 21.02pm and all the goods ordered were with me in less than twenty four hours, now that's what I call great service.


Bob Youldon

Thread: Snapping taps
21/03/2016 20:38:38

Good evening,

Arm yourself with a Eclipse 141 chuck type tap wrench for the smaller taps and a 142 and 143 for the larger sizes. Don't take the drill sizes for gospel check and check again, you don't need 100% engagement; also use Trefolex tapping paste for anything but cast iron or brass. Turn up some tapping bushes, something to keep the tap square to the hole at all times. Generally in the home workshop carbon taps are more than adequate provided you keep them well lubricated and don't buy cheap rubbish, there are still good makers of carbon taps and dies out there. Good advice from KWIL



Thread: Centre of a cylinder casting.
04/03/2016 15:49:31

Good afternoon George,

When you're ready to get started on your boiler let me know and I can send you a series of photographs how I construct mine also some words and music that'll make the job that much easier to achieve. Are you a member of a club? It is always helpful as there is always advice.



02/03/2016 11:52:48

Good morning George,

I think most people have given good advice, what I would say it is essential to work from a datum and I make that the port face, Put a rule all over the casting to determine roughly how much is to be taken off each face, I then carefully set the casting up in a 4 jaw to run as true as possible and face off what will become your port face, that is then your datum for marking off all the other dimensions. What you will need also is a small supply of say 13 gauge annealed copper sheet, cut just smaller than the finished faces, this will protect those newly machined faces from any damage from chuck jaws etc. As for marking out the bores then a couple of pieces off a broom handle forced in the bores, I will pin a couple of odd pieces of brass or copper sheet on the end of the wood plug as it is easier to mark out than the wood.

Having built three of the Don Young designed 4Fs I can safely say it's an excellent design, if you can get hold of the words and music, read it and read it again, you'll find it a great project.

If you need any advice on their construction etc then drop me an e-mail.



Thread: Rosebud
13/02/2016 11:47:34

Good morning all,

The so called "Rosebud" grate isn't that new; recently looking through an edition of Don Young's Locomotives large and small he describes a very similar grate for his design "George" The full sized locomotives designed for Rosebud Lignite had a vast grate area in comparison to those locomotives operating on the more normal bituminous coals, I think it was a yard foreman on the Northern Pacific commenting on Rosebud lignite reckoned it needed another million years in the ground!



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