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Member postings for Bob Wild

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

Thread: Java 0-4-2 O+K De Maas Sugar Mill Locomotive
06/04/2021 15:48:33

Brilliant, I'll be watching your progress avidly.

Bob

Thread: How on earth do I build this boiler for my Fire King ?
01/04/2021 19:44:50

Thanks Nigel. More good ideas.
Bob

31/03/2021 23:03:59

Thanks Jason, this is all getting very interesting. I like the idea of a separate ring to take the rivets. In fact I have some round headed ba screws with no slot. I could use these and they would look just like rivets.

I can certainly increase the height of the shell to increase the separation of the top dome and smokebox ring.

I am considering doing away with the cone shape on the outer lower ring which would mean I could just extend the whole outer shell down to the bottom of the boiler. And as you suggest I could use an L shaped ring to hold some dummy rivets.

If I increase the angle of the inner cone I can make it butt join directly with the outer shell. I don't mind not having any rivets at the base since this is right at the bottom of the boiler and right out of sight.

I can get rid of the 12 bent fire tubes and replace them with a couple of pairs horizontally across the top of the fire box.

Not sure if Cherry Hill would approve of all these changes, but what the heck. I am starting to draw this out (slowly).

Incidentally I have spoken with Gégé and he tells me he did use a gas burner in the end. I presume this also will give a higher heat output than the spirit version. He also said he made the conical parts by wrapping a sheet round a former and the soldering the seam. I would have preferred to use a tube the same diameter as the small end, and then try and swage it up a former. Any thoughts?

Bob

30/03/2021 16:50:51

Chaps, thanks for so many constructive and detailed points. I think the general consensus is that it could be simplified' I have had a few thoughts about this and will post a sketch shortly. I do have a few specific queries:

Nigel - what is a fire hole tube? The design shows a spirit burner mounted directly below the boiler. A bit more iinfo on the spear point would help.

Jason - How do you fasten dummy rivets to the copper tube. I like this idea.

Keith - I looked up "Keith Hale" on Amazon books,

I have been in touch with Gege in France who has bee most helpful, and also Werner in Germany.

Having read up about the Fire King it seems that the boiler was not lagged. Another interesting fact is that the total time for working pressure to get underway was about 6 minutes!

Bob

Edited By JasonB on 31/03/2021 07:08:35

Thread: Merryweather Fire King
28/03/2021 23:12:42

Nearly finished the engine, and started to think about the boiler. So I posted this thread to aim at a wider audience, asking for advice on what, to me, looks like a daunting part of the build:

https://www.model-engineer.co.uk/forums/postings.asp?th=172017

Looking for any helpful advice.

Bob

 

Edited By Bob Wild on 28/03/2021 23:14:22

Thread: How on earth do I build this boiler for my Fire King ?
28/03/2021 23:08:41

Here is an assembly drawing for my boiler:

boiler assembly.jpg

There are many features which frighten me:

  1. All the various rings are supposed to be rivetted. Surely I must solder all the parts to make them steam tight?
  2. The rings are supposed to be copper, but I can't find any supplier of solid material that size (approx 4in dia). But I have found a foundry that can cast them in brass. Would that material be OK, if the price is right?
  3. What is the best way to make the conical inner part. Should I start with a piece of tube with the same diameter as the smaller section and bash it up a former. Or should I start with a tube the same as the larger diameter and try to spin it down? Or should I even prefabricate it from sheet wrapped round a former and soldered at the seam?
  4. There is a pipe in the centre called the "Steam Supply Pipe" (is this a superheater pipe?) which has a 180 deg bend. This pipe is 6mm OD with a 4mm inside radius. How on earth can you bend this?
  5. Finally, and this is the scary bit, how am I going to solder it all together? Do I need different melting point silver solder, and in what order should I try to assemble it?
  6. I've just read a biography of Cherry Hill in which it explains that all her beautiful models were built to run on air only. If that was good enough for her, then it could be for me as well. In which case I could leave out most of the internal parts and simplify things enormously, let alone worry about making it steam tight.

Any advice from those more experienced than me would be most appreciated.

Bob

Thread: Merryweather Fire King
19/03/2021 22:56:30

Finally got all the parts for the engine finished. First the crossheads:

cross heads.jpg

and with the pistons and crankshaft:

img_1117.jpg

and to show my new toy milling machine, working on the eccentric rods:

milling eccentric rod.jpg

milling eccentric rods #2.jpg

and finally the valve chest and other bits:

valve chest etc.jpg

Spent ages lining everything up and getting things to move almost freely. I've got a way of mounting the assembly on the lathe so I can then try and run it in and get it rotating smoothly.

Thread: What is running-in oil?
10/03/2021 22:44:22

Thanks chaps for all your helpful and interesting comments. They certainly have given me something to think about.
I understand that the purpose of lubrication is to reduce friction and reduce wear, which is why I wondered if running in oil had some extra ingredient. Perhaps I should have included a bit more info in my original post. I am most concerned about the three crankshaft bearings. After some considerable effort lining them up I got them to the state where you could rotate the crank by hand, but it would not spin freely. I left it running at about 500 rpm for 4 hours but that didn’t make any significant difference. Perhaps I am asking too much. I do have some grinding paste and was wondering about lapping in the bearings with a dummy shaft. Any thoughts?

Bob

09/03/2021 12:20:04

Slowly getting to the point of finishing the engine for my Merryweather Fire King. I have read that it needs running in with a special running-in oil. I cursory search reveals that such products do exist, but they seam to be aimed at cars, and come in 5 litre containers. So, what is this oil, and can I get just a cupful ?

Bob

Thread: What nut and bolt material?
15/01/2021 22:31:38

Never dreamt that my simple question would provoke such a heated discussion. But apart from Hopper’s suggestion about a bit of brass bling not many other posts address my initial issue 🙁

14/01/2021 11:48:05

Thanks Hopper.

Paul - that’s a good idea. I like a bit of bling. And I have some brass nuts left over from an earlier job, so I can try those.
Bob

Thread: Merryweather Fire King
14/01/2021 00:03:43

Oh this is so hard (for me). Not much progress in the last two months, but a lot of effort. Got the leak test going on the water pump and it failed miserably. The culprit being the soldering of the cylinders to their backplates. I figured out that I was paying too much attention to appearance by putting a neat bead of solder between the mating faces. So, two attempts later I finally smothered the joints with solder and ‘Bingo’. It finally was sealed OK.

The present nightmare is getting everything lined up. Each cross head has the water pump piston rod and the engine piston rod at opposite sides. The cross head thickness is 20mm and I would have liked to thread them both from the same side. But I don’t have any taps that long. So I had to tap them separately from each side. The only way I could think of to get the two rods aligned was to hit them with a big hammer (well a small one actually) and finally they do run more or less true. The challenge now is to get everything in line. That means four rods, four pistons, four crosshead columns and two cross heads with their column guides and crankshaft slots. Added to that I’be discovered that the pump rods are 10mm short (how did I miscalculate that?). So a bit more rework again! I did manage to get the crankshaft to rotate a bit until it fouled so I’m quite hopeful in that respect. I did get a tip from another member where he suggested that you could drive the crankshaft with the mounting nuts fairly loose and progressively tighten them over a period of hours. We shall see!

And another thing, I‘ve just got round to drawing out the boiler (because it’s snowing outside and can’t work for more than an hour in the workshop). Goodness only knows how I’m going to make that with twelve curved fire tubes, a very complicated super heat tube, not to mention the conical body. But that’s for another day.
Bob

Thread: What nut and bolt material?
13/01/2021 23:12:14

I’ve been building my Fire King for a year now. I notice that many of the nuts and bolts that have been in for a while are starting to look a bit tarnished as if starting to go rusty. That’s not pretty to me. So, I hit upon the idea of replacing them with stainless steel ones. Is this a silly idea or are there any alternative solutions?

Bob

Thread: Has anyone bought and built a Myfordboy engine
05/01/2021 22:47:55

I built his traction engine. A few pics here:

**LINK**

Quite pleased with the castings and drawings although I did customise it a bit to make it look a bit better (to me). David Abbot, myfordboy, was most helpful and answered my email queries.

Bob

Thread: Workshop temperature - cold
04/12/2020 22:58:33

What a load of wimps on here. Just spent an afternoon in the workshop at 1.0 deg C. Done a load of milling with a glove on one hand to reduce the conductivity from an aluminium handle. But it was most successful 😋😋

Edited By Bob Wild on 04/12/2020 22:59:31

Thread: Lady Stephanie
27/11/2020 23:21:27

Bother. I wish I had seen this thread earlier. I built Lady Stephanie recently. No problems but the supplied drawings were almost unreadable, so I used the magazine articles. There is a funny story (now). The entablature casting was terribly distorted so I sent it back to the address on the drawings. No response after a while so I phoned Reeves. They said that they moved from that address many years ago so my parcel was lost! They refused to send me a replacement until I gave them the original. Despite the fact that they had given me the wrong address they were unrepentant and I had to give up in the end. So I prefabricated the entablature myself in the end and put Reeves on my list of non-preferred suppliers 🙁🙁

Thread: Good YouTube videos
21/11/2020 22:03:55

Where’s Clickspring. He’s very good but hasn’t posted for ages?

Thread: Cosworth V8 1:12 scale
15/11/2020 22:50:44

Very impressed!!

Thread: Merryweather Fire King
11/11/2020 23:00:44

These brackets look fairly straightforward, but they have given me a real headache. So I thought they deserved a mention in my build thread::

too big brackets.jpg

The drawing called for them to be bent from 3mm strip. But I wasn't confident in making the double bends in the right place, so decided to machine from solid. Two pieces were glued together so I could machine them as an identical pair. I chain drilled first to remove as much metal as possible:

chain drilling.jpg

This is where the problems started. Because I'm using Stuart cylinders I had to recalculate the width, and somehow while allowing for the 3mm thickness I ended up with then being 3mm too wide. I couldn't face throwing them away and starting again, so I cut off one face and screwed and glued another piece of machined angle. This gave me the opportunity to use JB Weld for the first time:

correct brackets.jpg

I painted the chassis while I was at it, and here is the pump assembly finally in position:

pump assembled.jpg

Next up, a leek test. I have learned from bitter experience not to delay this!!

Thread: Grumpy old men
10/10/2020 22:53:20

People who say “myself” when they really mean “me”

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