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: Mabel, lbsc|
I think you will find that the only full set of drawings for Mabel is for the 3½" gauge version which is available from Reeves.
|Thread: Simplex Superheater Details|
the superheater is a single out and back made from 7/16" x 20g stainless tube. It is a fully radiant type extending right to the back of the firebox.
|Thread: Rob Roy Boiler|
I think it would be a devil of a job to try and remove the backhead at this late stage of the game although I do see your point. I think you would probably finish up wrecking the boiler.
Edited By John Baguley on 13/05/2017 17:09:38
You shouldn't have a problem silver soldering in the bushes on the front tubeplate. Just make sure that you flux all the exising joints as they may well melt again.
I've added bushes on the backheads of a couple of Tich boilers for someone without problems and that is much harder than working on the front tubeplate.
One point about having to extend the firebox sides on such as Rob Roy boilers - offset the cut in the barrel for the part that has to be folded down to make the firebox sides such that you only have to extend the one side. Just makes it a little easier. I prefer to make the firebox wrapper as a separate piece and joined to the barrel with a joint ring or an overlapping joint. That eliminates the need for the extension pieces.
I opted to use 1/8" rivets when I built the boiler for my Helen Long. These were threaded 5BA and put in with the heads on the outside and brass nuts on the inside of the firebox. I didn't fancy trying to silver solder the stays inside the very narrow firebox so opted for the brass nuts caulked with Comsol. It's a method that I personally as a boiler inspector don't have a problem with and I think it's a much easier way for a beginner to get a good boiler until they gain more experience. The heads of the stays were siver soldered on the outside as this is relatively easy to do.
The outer wrapper and the firebox wrapper are both 1/16" (1.6mm) copper and the original stay spacing by LBSC was given as 3/4 x 3/4. I consider this too far apart for 1/16" copper sheet and reduced it to 5/8 x 5/8.
|Thread: Myford paint colour|
Not at the moment. I've got a poorly leg and can barely get up and down the stairs at all
|Thread: Using nitrile balls in clack valves|
I've used O ring seats for clack valves with success after seeing an article by Jim Ewins on his Loadstar locomotive. Just make sure that the O ring is retained so that it can't lift with the ball. They make good check valves for lubricator oil supplies.
A commercial design of clack valve uses a poppet fitted with an O ring that seals on a flat seat.
A possible alternative to stainless balls is silicon nitride (ceramic) balls. These are said to be harder than and have a better surface finish than steel. Not my idea but Roger Froud on the MECH forum is using them in his Speedy build. It will be interesting to see how they work out.
|Thread: Myford paint colour|
A bit like when you dash upstairs for something and forget why!
|Thread: Table 2 Query : The Missing 98%, ME4558|
Row 5 should read 'Heat transferred in firetubes'.
Jim's original articles appeared in ME 1966, March 18th, April 1st, and the table in 20th May.
Edited By John Baguley on 08/04/2017 15:25:20
|Thread: Myford paint colour|
1973 - Red
|Thread: Rivet and Bolt cropping|
I drill a clearance hole through a suitable thickness piece of steel, push the bolt,screw/rivet through, hold in place with a file handle or similar, and then cut off the surplus with a fine tooth saw. A rub over the end with a fine file gets rid of any burrs. If you have a lot to do it would be better to harden the steel so it doesn't get worn down by the saw so easily.
I tend to buy the longer length bolts as they are not much more expensive than short ones and it saves keeping a large stock of different sizes.
Mike Boddy in Australia designed and had made a cutting tool very similar to the crimping pliers but specifically for bolt shortening. I've got one of his prototype sets in the workshop and they work very well. I think they cover BA and metric sizes. He was looking to find someone to import them for him to keep down the cost but I don't know what the situation is at the moment.
|Thread: What Did You Do Today (2017)|
Hopefully there will be a shear pin somewhere in the drive train to the leadscrew. If so, that will probably have gone.
|Thread: Local mirror silvering services ?|
Those books were my bible as well and I still have them, although I gave up astronomy many years ago now.
I used to send mine off to be aluminised and overcoated. Can't remember where now but I presume such firms still exist?
I did silver a 12" mirror myself once which wasn't particularly difficult. The problem nowadays would be getting hold of the chemicals - IIRC silver nitrate, concentrated nitric acid (for cleaning the glass), ammonia, sodium hydroxide, and dextrose. I got my chemicals from the local chemist but those days have long gone unfortunately.
Silvering can be a bit nerve racking as you can get silver fulminate formed during the process if you don't mix the chemicals properly!
|Thread: injector problems still|
Sorry to hear that you are still having problems.
Can you borrow an injector that is known to work reliably e.g. that is taken off someone else's loco? Swap that for one of yours and see if it makes any difference. If the other injector works then it's your injectors that are the problem. If the other injector doesn't work either then there is something wrong with your pipework etc.
Your problem suggests two possible causes to me (assuming that the injectors are not at fault). Either the steam supply to the injector is restricted somehow or your clack valves may not have enough lift on the balls.
Are you using commercial valves for the steam valves? Sometimes the passages through these valves are too small, especially on the globe type valves.
Injectors often need more lift on the balls in the clack valves than those used for hand pumps and axle pumps.
What size injectors are you using? If you are using say 24oz then try an 18oz. The smaller injector will need less steam and water so may work if the supplies are not enough for a 24oz. If the 18oz does work then you need to look at the steam and water supllies.
Have you got filters in the tender for the injector supply? If not, you could be getting muck in the water supply which will stop the injectors working after a time.
Be careful not to go overboard with pickling the injectors. The acids will eventually damage the brass cones and affect performance.
Edited By John Baguley on 14/02/2017 07:21:05
|Thread: Quality digital vernier calipers|
Keep a look out on Ebay for s/h Mitutoyo. etc. You can get some real bargains for a lot less than the full price.
After using the cheap Aldi ones for years (and I've been perfectly happy with them apart from the very short battery life) I've recently bought several s/h Mitutoyo calipers and micrometers quite cheaply. Some are in almost new condition but some have the odd scratch or two. Also bought a few 'faulty' ones that just needed cleaning and now work perfectly. I couldn't believe that the batteries are supposed to last for over 2 years!
As mentioned, watch out for the cheap chinese copies. You are not going to get a genuine brand new Mitutoyo for £10!
|Thread: accurate measurement of steam temperature|
Yes, the late Jim Ewins did it on his O-6-2T loco and measured the temperatures at many points in the boiler, flues, etc. under various load conditions. His results were written up in ME for 18th March, 1st April, and 20th May 1966.
It is interesting to note that the maximum superheat temperature measured was 378°F (192°C) giving a final steam temperature of 620°F (327°C). The maximum superheater temperature recorded was 1570°F (854°C!)
|Thread: denham junior mk2|
I didn't put these pics on my website but here are a couple of the reversing gears in the gearbox - right hand side of photo:
This is part of the gear assembly that does the reversing - bottom right of the photo
I've got a CAD drawing of the gear assembly and bronze bush that I did for someone some time ago. Funny enough, they were missing the reverse gears as well. It's not the same lathe is it by any chance?
Edited By John Baguley on 19/01/2017 01:43:13
Edited By John Baguley on 19/01/2017 01:45:00
Edited By John Baguley on 19/01/2017 01:46:40
Check your pm box.
|Thread: Stirling Single|
the Greenly drawing gives the tread diameter of the driving wheels as 4.0625". The bogie wheels are 1.96875" diameter and the trailing wheels are 2.21875. The tender wheels are the same as the bogie wheels.
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