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Member postings for John Baguley

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

Thread: super Heaters
28/10/2015 20:02:17

Hi Ron,

I am a big fan of superheat, the higher the better, and woudn't build a loco without it. It does make a big difference to the performance of the loco despite what the negative people will tell you. Less water and coal used and much livelier performance. With an unsuperheated version you get a shower every time you run, especially in cold weather, and you can't see where you are going half the time. Fully radiant versions that extend over the fire are far more effective than ones that just sit in the flues. They just dry the steam a bit but don't increase it's temperature very much. Go for it! Superheaters are not difficult to make. Forget the coax type though. Doug Hewson did some tests that showed they were pretty useless compared to the proper hairpin type.


Thread: Lathe paint
25/10/2015 16:33:38

Another vote for Tractol. I got mine off Ebay as Smith and Allan have a shop on there. May be cheaper direct. Take care if you use the industrial etch primer as it's quite nasty stuff. You need to wear a mask and have plenty of ventillation. I got a very good finish just using a brush.




Thread: What did you do today (2015)
15/10/2015 20:28:48

Spent the day at the Exhibition on the National 2½" Gauge stand. Very busy. Left home at 06.15am to avoid getting stuck in the works traffic. Got there for 08.00am. Last year I left at 07.00am and it took me 2½ hours! Same again for the next 3 days. No traffic though on Saturday and Sunday so can leave home later thank goodness!


Thread: 3 1/2" gauge wheel casting indentity help
12/10/2015 19:57:12

Just happen to have a copy of this on the computer:

stuart wheel codes.jpg

Thread: 08 Shunter in 2 1/2" Gauge
05/10/2015 18:58:39

HI Simeon,

Following Jason's suggestion have a look at Technobots website. They sell small chain and sprockets. They also have a sister company with a greater range.


Thread: ME 4517
17/09/2015 11:26:50

Arrived this morning


17/09/2015 00:13:54


Thread: Black 5 Boiler well under way now
16/09/2015 12:21:52

Looks good Ron smiley


Thread: Steam Injector for my Black 5
16/09/2015 00:29:00

+1 for the Ted Crawford book. I got a copy some time ago and if you want to delve into the theoretical side of injectors then I think it is the better book. However, by following Derek's original articles in ME I did manage to make some 4oz and 8oz injectors that actually worked smiley

It's always surprised me that so far as I know no one has supplied the necessary reamers commercially. Must be a market there for someone wink


Thread: Coloured lamps
13/09/2015 19:33:12

Yea, not exactly cheap. If they are that hard to source now they can probably charge what they like for them frown


13/09/2015 18:32:31

These seem to stock the bulbs you want? Unless you've tried them and they are out of stock



Thread: Stafold Barn Railway
09/09/2015 10:14:57

Hi Ron,

Won't be going this year but have been 3 times now. Fantastic place if you like narrow gauge locos. You'll enjoy it smiley There's usually loads of road vehicles there as well - traction engines, vintage cars etc.

I think they have an open day 3 times a year but you have to apply for tickets - you can't just turn up on the day.


Edited By John Baguley on 09/09/2015 10:17:44

Thread: Too much steam going up the chimney
07/09/2015 22:07:38

Hi John,

Here are a pair I made for a chap at our club. They are for a 3½" gauge 75000 class loco which originally had plain stainless bobbins that leaked badly:

valves 1.jpg

valves 2.jpg

The valves consist of a central bobbin made of bronze, stainless, or even brass. The heads are rings of PTFE held onto the bobbin by threaded caps. You machine the PTFE heads to a push fit in the liners and the fit sorts itself out as soon as you steam the loco.

The bottom photo shows that I altered the method of valve adjustment to a much better method. The originals were adjusted by altering the nuts on the threaded valve rod which is a right pain to do. In my method the valve floats on a central 'bush' threaded onto the valve rod. To adjust the valve you just rotate the bush and secure it with a locknut. Think I got the idea from an article in an old ME

There's a bit of a description of these valves here:


Unforunately, I didn't take any photos of the bobbins before I assembled them but hopefully you get the idea. I might have done a CAD drawing before I made them, I'll have a look.

It might be an idea to see if you can check the valve liner bores to make sure they are truly round and parallel. It's possible they may have distorted when they were fitted to the cylinder block? PTFE heads will accommodate slight ovality etc. in the bores though but better if they are true.



Edited By John Baguley on 07/09/2015 22:14:16

07/09/2015 17:25:15

Hi John,

There's a very good chance it's the piston valves leaking. It's very difficult to get plain metal bobbins to seal well enough. Even if you machine them to as good a finish as you can and a good fit, the high spots soon wear off and the valves soon start to leak. Don's method is to make them a very tight drive fit, coat them with Molybdenum Disulphide greae, force them into the liners and keep knocking the valve from one end of the liner to the other until they become free. The idea is to remove all the high spots and leave the liner bore and the valve bobbin with a very smooth surface. I have to say I tried that some years ago but didn't have a lot of success with it!

I've given up with solid bobbins now and use PTFE heads with complete success. The only problem is that once you run on steam the valves will leak if you try and run the loco on air cold. No problem on steam though.

There are another couple of possible causes. The piston packing may be leaking allowing steam to blow past or the valve liners may not be sealing into the cylinder block and allowing the steam to pass straight from the inlet to the exhaust.


Thread: Bristol Show 2015
17/08/2015 00:05:33

Hi Bazyle,

Think it's the Tin Turtle built by Des Adeley that's hopefully going to be 'serialised'.

John (that JB)

Thread: 2 1/2" wheel profile
05/08/2015 18:01:17

I hope we are not divided, just catering for the different aspects of 2½" gauge smiley


05/08/2015 14:54:57

Just to add to Ian's post here's the wheel standards used by the N25GA:

2.5 inch gauge wheel standard.jpg

As we run mostly on passenger hauling raised tracks our standard is a bit coarser than that required by the G3 Society as we don't need to run through points etc. The width of the wheel tread is wider than the G3 standard, which can be useful when running on some raised tracks which are a bit over gauge in places! Some people with G3 standard wheels do seem to have problems running on some raised tracks as the wheels sometimes tend to fall between the rails due to the narrower treads.


Thread: Allan Brothers Lampless Oil Engine
22/07/2015 16:55:53

I give up! I'll go and do some gardening instead cheeky


22/07/2015 16:18:15

Just had a go at drawing it out and it seems impossible. To me, there seem to be some vital dimensions missing. You really need the position of the cylinder bolting face from the datum point. You can work it out from the drawing for the base. I reckon it should be 60mm. That makes the length of the slope at the datum end to be 32.45mm.

Can't understand why it's been dimensioned like it has. Don't like to be critical but It's a dreadful drawing.


Edited By John Baguley on 22/07/2015 16:23:51

22/07/2015 15:39:12

The cylinder centreline should be 62mm - 20 + 17 + 40/2. That is also the dimension given for the height of the crankshaft centre.

The co-ordinates do give X and Y - the decimal points should be commas! Yes, C1, C2, C3 are the centres for R1, R2, R3 and C4 is the crankshaft centre.

The 62mm length for the cylinder also seems wrong as it's much longer than the height of the cylinder centreline. Maybe the drawing has been distorted in printing?


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