Paddington Platework

[Gary L]

Apr 6, 2022 20:45:50 GMT Roger said:

Looks great Gary. I'm not so sure about the Expanded Polystyrene though. I did a test with some of it that's backed with a thin card, holding it against the surface of the test boiler, and it melted. You might get away with it if there's another insulator between it and the boiler, but I'd hate for it to stick to the boiler barrel and spoil the paint.

Oh, I thought that’s what you had decided on! Oh well, the stuff does melt, obviously, but there is ¼” of insulation and metal cleading round the boiler, and an air gap too, so I don’t think it will get so hot as to be a real problem. If it does melt, it will just contract locally; there won’t be rivers of plastic running everywhere, and it won’t be visible, so if the paint is damaged it will be out if sight. I’m relaxed about it.

Gary

[Gary L]

Following the DOH moment, I wondered if the (very) difficult access to the leaky nut on the Balance Pipe had meant it was not tightened as much as it should be. I couldn't get any further with a standard spanner, because it was too long, nor a box spanner or socket set because the top of the frame was too close. Nothing for it but to make a Special Tool, seen in the photo below alongside a standard 6BA spanner:



It was made from some ⅛" gauge plate milled down to 0.100", then oil-hardened, tempered, and the other end slotted to take a swivelling brass strip riveted in. And it worked! It was possible to wiggle the special spanner over the nut and pull with the brass strip, and it turned out that the leaky nut would take another 1.5 turns, and the others could be nipped up a little tighter too. It seems to have stopped the leak, thank goodness...

[stevep]

Your home-made one probably fits better than the commercial item, if mine are anything to go by.

[Gary L]

Apr 9, 2022 17:09:59 GMT stevep said:

Your home-made one probably fits better than the commercial item, if mine are anything to go by.

The one in the picture is one of a set I inherited, stamped 'Bedford Vanadium" on the back and they are rather good. Ditto a single Britool that came from I don't know where. Never heard of Bedford as a spanner maker. I wonder if Britool still make BA spanners? Certainly the stamped ones commonly available from 'the trade' are very inferior by comparison.

In some BA sizes, metric spanners work well, and there are some BA hex sizes (I forget which) where I understand some manufacturers use metric stock where the correct size stock is NLA. Needless to say, this practice doesn't sit well with properly made spanners, and I have some 'BA' nuts that my Bedford spanners won't fit on.

I'm sure the sensible way is to stick rigidly to metric sizes, like Roger does. Too late for me though!

Gary

[andyhigham]

Pipe nipple nuts are a prime example. For a given pipe size the hex size could be metric, AF or BA

[Gary L]

Apr 9, 2022 20:14:32 GMT andyhigham said:

Pipe nipple nuts are a prime example. For a given pipe size the hex size could be metric, AF or BA

Very true Andy. I wouldn’t like to try and count the time wasted trying to find the right spanner size. (Don’t forget that BSP fittings, which we might come across in the smallest sizes, probably have Whitworth hexagons to add to the fun. )

My Paddington project was begun by somebody else, and I didn’t want to end up with a mix of thread standards so I carried on with BA as per the drawings. That was before I found that all the threads on the boiler were metric anyway! And of course, the majority of proprietary fittings are imperial…

Gary

[Gary L]

The tanks are on, the fillers and vent pipes assembled, and an hour or three spent 'spotting in'... first priming, then dobbing some black on the most visible screw and bolt heads:



I've also painted black (by hand) most of the bare steel handrails, because that is the official Swindon painting style. Since the handrails are mild steel, the paint is desirable anyway for protection, however there are some 'funnies'. Officially the cab door handrails are left bare "except for 1" at each end". I don't know how that translates to the welded handrails on the 15xx, and the odd inch translates to ⅛" in this scale, so hardly worth bothering with, so I didn't. I've left the whole of the cab door handrails bare; I can always touch them in later if more infortmation comes to light. Visually, they balance (to some extent) the other 'funny', which is the distinctive GWR smokebox handrail. By rights this should also be black, as should the smokebox door handles and boss. However the latter gets a lot of handling and I doubt if paint would stay on for long, even if they were not stainless. For the smokebox handrail, I used ready-made stanchions, and these too were stainless. At first I tried to form the handrail itself from stainless, but it was very difficult stuff to bend, and I decided that I didn't like the garish appearance anyway, so those too are BMS. I don't think I will attempt to paint them, on practical grounds; i.e. if ever it is necessary to remove them, it will make a horrible mess as they slide out through the stanchions...



The loco might look close to finished (if they are ever truly 'finished') but there are still a few outstanding things to do. First is to uprate all the suspension springs, because the loco is on the stops with the Adams-recommended 70 lb/in springs; it certainly can't be run in its present state. Then there is the safety valve bonnet. This is not needed from the functional POV, but it is worth taking some time and trouble to get right, and it is likely to take quite a lot of both, so several more posts about it will be coming in due course. Finally, the removable sections of the cab roof and rear will need to be tackled, though these are very low priority.

[Deleted]

That's looking fantastic Gary... great job sir..

Pete

[Gary L]

Thanks Pete
Gary

[terrier060]

I would love to see that running Gary - the 5" version is one of the best 5" locos in my opinion, transportable in the average car, yet very powerful. Your 7.5 inch version will be great, and a large locomotive and VERY powerful.
Ed

[Gary L]

Axlebox Springs

As noted previously, all the suspension springs needed to be changed, because the David Adams-estimated 70lb/in spring rates proved to be significantly too light. The platework in total has added significant extra weight to the loco, so it would not have been possible to finalise the springs before now. I don't think my Paddington has any reason to be significantly heavier than if built strictly to the drawings. (Hmmm! If built strictly to the drawings it would be pile of parts of which many wouldn't fit together! ) The few pounds of lead in the bottom of the tanks is an extra, but the tanks themselves contain slightly thinner sections of brass than the drawings specify, as does the cab (though in the latter case only the difference between 1.5mm and 1/16" plate thickness). So these few notes are included for the benefit of any Paddington builders following after me...

It probably won't surprise many of the old hands that after investigating other suppliers, it was only Lee Spring that had sufficient range of stock and competitive pricing. Even then I wouldn't describe them as cheap, but their 'competitors' were without exception, way out of sight. I haven't used Lee Spring before, but their service was prompt and efficient, and they will be my choice again if I have to buy more springs in future. I'm therefore quoting the Lee Spring product codes below.

The prototype loco has a ton or so less weight on the rear axle than the other two (18T 16cwt versus 19T 14cwt to be exact), so it seemed reasonable to expect a difference in the model too, especially since at one end the cylinder assembly is certain to be proportionately heavier than full size, and at the other end, the bunker carries no coal. So for the rear axle I chose 4 off LC 095J 04 M with a rate of 95.43 lb/in. These are music wire, with a zinc plated finish (I think I'd have preferred plain black steel, but couldn't find the option in the list).

For the front two axles, my first choice was 8 off LCD 250SK 02M with a rate of 100.8 lb/in, also with plated finish, but they were not in stock and a delivery delay quoted of a month. So I substituted LHL 750A 03 with a rate of 115 lb/in. These are from a different range (die springs) and have a grey powder coat finish. I'm not troubled by the difference in finish, as the axlebox springs operate in a dirty environment and are impossible to keep clean, so they will quite quickly get covered in a black paste of thick oil and track dirt. It will also help anybody dismantling the supension in the future to identify which springs go where. Here is an inside view of the driving axle:



My first thoughts are that the slightly increased rate of the substituted springs was a happy accident, and my first choice might have been a smidgeon too light. It was all very much a matter of guesswork not calculation, but it seems to have worked out about right. I haven't adjusted the springs at all yet, just assembled them all with about half a thread protruding below the adjuster nuts for the time being. The axleboxes seem to be just a little below mid-travel in the horns, so some judicious tightening of the nuts might be needed, but probably not a lot (what do others think?)

There is no means of locking the adjuster nuts in position once set. Is this normal? The spring pressure is likely to inhibit any slackening, but is it safe to rely on this?

Gary

[Gary L]

Apr 13, 2022 22:04:23 GMT terrier060 said:

I would love to see that running Gary - the 5" version is one of the best 5" locos in my opinion, transportable in the average car, yet very powerful. Your 7.5 inch version will be great, and a large locomotive and VERY powerful.
Ed

Thanks Ed, I hope you are right! I am quite keen to see her running myself, but I'm not going to rush things or take silly risks. But I'll be sure to video the first run and share it on here.

I think your comments about choice of prototype are spot on. I've never fancied inside cylinders for a model subject, because of the maintenance issues. In 7¼" gauge, most tender locos present significant transport challenges, so a tank engine it had to be, indeed a six-wheeled tank engine to keep the length sensible (I've nowhere to park a trailer). So for a Western fan, the 15xx is the only show in town apart from a couple of classes of very small tank engines, which are comparable in capacity to Bridget, my other loco. Bridget is a fine design, and can be lifted conveniently by two men (which is out of the question for Paddington) but this does significantly inhibit her haulage capacity (two carriages max on our club track).

LBSC's Speedy has a number of 'issues' as Roger will testify, but once properly 'sorted' it is a reliable performer on 5" gauge, and I enjoyed my Speedy for a number of years. By reputation Paddington is similar in 7¼", I certainly hope so!

My car (Toyota Verso) is perhaps a touch above 'average' size. Paddington fits inside very conveniently in her travelling 'crate' though the weight might be an issue- I've not yet transported her 'fully assembled.' It will all be very interesting!

Gary

[terrier060]

Yes - my Terriers are not much bigger than a 5" Speedy - very small for a 7.25 inch gauge loco - but a very pretty engine both in Stoudley's and British Rail livery. The only thing I think spoils the A1X version is that ugly brake pipe which seems like an afterthought. I am sure they could have made a better job of that! Stroudley would have hated it and propbably made it run along the top of the side tank.

I love your backhead fittings and glad you have kept the atomising valve. I know there are several modellers that say this is unessessary and leave it out, but they forget that this is the valve that shuts off the steam when the loco is coasting or stopped as well as sending the oil to the cylinders as a mist. Mine worked very well on my tank engine.
Ed

[92220]

Hi Gary.

The loco is looking good!! You say about the weight for transport. I obviously have the same problem, with a much bigger loco. I bought a secondhand Liko Golvo 9000 disabled patient lift for handling the loco. The crane has a max load of 250Kgs, so is capable of lifting quite a large loco. It looks quite heavy but I found it easy to reduce the size a bit and it comes apart, into 2 pieces with just undoing 1 hex cap screw, to become very easy to handle, It is all aluminium construction. Dismantled into the 2 pieces, it fits in my car fine, with the back seat folded down, along with the loco and tender, and the car is a standard Vauxhall astra, so your car, being larger, would take your loco and a disabled patient crane, easily. There are a lot on Ebay for very reasonable prices. The Liko Golvo is Swedish made. As well as electric lifting, the legs also spread in and out sideways, electrically, to make the crane extra stable with heavy loads. Also, the batteries seem to have a long life between charges, and there is a battery capacity indicator.

Bob.

[Gary L]

Apr 14, 2022 22:54:14 GMT terrier060 said:

Yes - my Terriers are not much bigger than a 5" Speedy - very small for a 7.25 inch gauge loco - but a very pretty engine both in Stoudley's and British Rail livery. The only thing I think spoils the A1X version is that ugly brake pipe which seems like an afterthought. I am sure they could have made a better job of that! Stroudley would have hated it and propbably made it run along the top of the side tank.

I love your backhead fittings and glad you have kept the atomising valve. I know there are several modellers that say this is unessessary and leave it out, but they forget that this is the valve that shuts off the steam when the loco is coasting or stopped as well as sending the oil to the cylinders as a mist. Mine worked very well on my tank engine.
Ed

Thanks Ed

I don’t know if ‘technically’ it is an atomising valve, because the device that did the actual atomising in Swindon’s design is absent. But it is certainly a shut-off valve. Some sort of shut-off must be needed, or the cylinders would be full of oil after a long stand. I think that without it a manual shut-off is needed, but I didn’t see any fun in that.

Gary

[Gary L]

Apr 15, 2022 8:27:16 GMT 92220 said:

Hi Gary.

The loco is looking good!! You say about the weight for transport. I obviously have the same problem, with a much bigger loco. I bought a secondhand Liko Golvo 9000 disabled patient lift for handling the loco. The crane has a max load of 250Kgs, so is capable of lifting quite a large loco. It looks quite heavy but I found it easy to reduce the size a bit and it comes apart, into 2 pieces with just undoing 1 hex cap screw, to become very easy to handle, It is all aluminium construction. Dismantled into the 2 pieces, it fits in my car fine, with the back seat folded down, along with the loco and tender, and the car is a standard Vauxhall astra, so your car, being larger, would take your loco and a disabled patient crane, easily. There are a lot on Ebay for very reasonable prices. The Liko Golvo is Swedish made. As well as electric lifting, the legs also spread in and out sideways, electrically, to make the crane extra stable with heavy loads. Also, the batteries seem to have a long life between charges, and there is a battery capacity indicator.

Bob.

Thanks Bob, and that’s a most interesting idea. Transferring the loco from workshop to car is not a problem, at least not in principle. A combination of a hydraulic lifting trolley, rails in the travelling ‘crate’ and a portable ‘bridge’ over the workshop threshold takes care of that, though some aspects need beefing up a bit I think. There are similar arrangements available at the other end too. But what is a bigger challenge is getting the loco onto a rolling road for testing; the required lift to get the rollers underneath is impossibly high. I could do it with Bridget and Speedy, but Paddington is far too heavy. So a crane like you suggest might be the answer, and come in useful for other things too. I shall have to investigate further.

I wish I had the slightest idea what 250kgs looks like in practice !

Gary

[andyhigham]

250Kg x 2.2 = 550 lb or around 10 sacks of spuds

[uuu]

Station Road Steam has an archive entry link suggesting 200Kg for a Paddington model.

I have a Golvo lift too - bought from ebay. There are sellers expecting hundreds for them, but patience will find much cheaper ones turning up form time to time.

Wilf

[doubletop]

I'd suggest that 200Kg plus is a bit on the heavy side.

Because the Dart is an 0-4-2 I built a weighbridge so that I could get the springing right and get the weight over the driven axles. Looking at Garys thread and mine the parts we've been making are so similar the overall weights should be similar. I have around 10kg of lead in the front of each tank and another 8kg slung under the cylinders. Total weight of the loco is around 110Kg. The shipping weight for the Polly plating kit was 11Kg so I can't see the weight going up that much.



(This is probably the rear axle.)



The quick test is to prop the loco on both buffer beams and then lift the each end (one at a time) with a pair of 50kg baggage scales in parallel, giving a 100kg range. Sum the results. When I weighed my loco that way I think I used an 'A frame ladder as the hanging point.

Pete

[andyhigham]

I have a Golvo lift, rated at 300Kg
It picks my Lister D engine up no problem