Mickoo's BR modelling

mickoo

mickoo

Western Thunderer
It's slowly getting there :headbang:

The splashers, well, the outer face has nice little slots in the footplate for the tabs to fit in, they are correct at 6 mm from the rear edge, but, the splasher top is only 5 mm wide :eek: The footplate has a nice little half etch recess at each end for the splasher brackets, again only 5 mm wide.

So, chore #1, fill all the footplate half etch recesses with 10 thou shim, then make all new wider splasher tops and finally new fixing brackets....not yet done, I still have to add the splasher rears to enclose the driving wheels, but I knew I had to do that before I started the rest.

Frames, these have nice half etch dimples for pressing the rivets out and very helpful half etch markings for the variations in frame lightening holes, problem is, you can see some of this under the boiler, so a new inner skin was made to cover all that up and then it was obvious that I'd need some horn guides etc. For no other reason other than I can, I made some new ones, I have got some hobby horse ones on order but I'll keep those for a later date as I'm moderately happy with these.

The scrap etch bin has grown from previous attempts but finally I have a workable solution, read, if you do something enough times you'll get it right once in a while!

There's no inner skin behind the aft stretcher which leaves a small gap at the top of the horn guide, I'm fairly sure this area is almost invisible once the boiler goes on so may just opt to fill the small gap with 2 part epoxy and have a slightly thicker base plate. In hindsight if I'd thought I'd be doing this now when I started out, then the whole frame area around the drivers would have had a new inner skin, rather than the patch work I have now, none of this helped by the previous builder cutting out all the axle holes.

Still to do, well, the same on the other side, then some splasher rears and pseudo brackets, a new inner cylinder casting, or at least some sort of rough facsimile, some more stretchers and plate work and some of the larger pipework and some axle boxes to cover the hornguide rear face, then I'll see how that looks before doing any more in there.

Before
IMG_6043a.JPG

After
IMG_6045a.JPG

Most of the hornguide is brass but I gave up trying to solder in the side fillets.....more scrap brass in the scrap bin!..... and had about given up (hence order to Hobby Horse...which are not strictly right for an A3 or any of the other Pacifics I've looked at truth be told) and begun to consider making them out of Plasticard when it struck me, I only need to make the fillet from Plasticard and glue in with 480, it's not load bearing but the adhesive is so good you can trim the Plasticard afterwards and I've not had one break off yet. Once painted I don't think I'll notice the difference, especially down in there.
 
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Steve Cook

Steve Cook

Flying Squad
Nice job Mick :)
Not sure if it would have been easier, but rather than fiddle with the tiny fillets, I've read of a technique where you would make a cut through the hornguide bearing face (ie in the same plane as the axles, right down to the frame mounting face), right where you want a fillet to be. You can do both sides of the hornblock at the same time, then fit in a strip of brass across the whole guide and solder in place. The strip can then be filed to shape on the outside to create the fillets, the centre can then be cut free. I don't think its ideal if you have working hornguides as it means the bearing face has been cut, soldered and filed, but it can be less sweary than trying to hold and solder tiny bits of brass.
Steve
 
mickoo

mickoo

Western Thunderer
images.jpg
Steve, of course, hadn't thought of that, it's how Finney and some other kit makers produce the small fillets on the smoke box saddle front and rear, long strips longitudinally that poke out the end and trimmed to suit the required shape. I will need to do that with the A3 as the supplied smokebox saddle casting is......wrong :( All I need to find now is a 20 thou thick needle file or a way to cut 'straight' 20 thou slots LOL.

You could us a variation of the above, in that you make the fillet strips first and file the curve at each end, then solder the fillet strip to the back piece and then cut the middle out and add complete guide faces, still a little messing around but maybe easier. The one down side with the Gresley hornguide is that the fillets are not even, the top two are in alignment with each other, but the bottom two are not.

Here's a rough photo of the evolution of mine, but not showing the final version, as they're all fitted to the loco.

Image1.jpg

Starting from the left

#1 wrong size so didn't get any further
#2 right size but top radius much too excessive and rivets wrong location
#3 right size but top radius still too large but carried on regardless. Here the top part is one strip with the top fillets angled up from it, each fillet is filed from below so that the centre section drops into the axle box guide, easier to hold and solder. Then there are two vertical guides soldered on and four individual fillets. Again the rivet pattern is wrong and the lower fillets are in line....incorrectly.
#4 right size, better rivet pattern but mis-formed as the GW rivet punch had moved a fraction and was not in line with the anvil, the top strip is as before and is as on the final copy, for the side guide I bent over the top to form the top side fillet which required only two individual fillets at the bottom. However, this placed the top side fillet hard up against the top angled one....incorrectly, there should be a small gap.

The issue with soldering the fillets was that everything else ran the risk of starting to unsolder so to #5

#5 the side guides are bent up from the base plate, it's almost impossible to bend something that thick, even with score lines on the back, that small and with rivets close by accurately, another non starter.

The final solution was basically #3 but with side fillets made from Plasticard and glued with 480, the shape was refined and made more accurate. I'll take some photos of the next three as I go along so the basic shapes can be seen. None of the above have the tapered guide face, #6 does, detailed below.

One thing to watch with Gresley hornguides are the guide faces, that which you can see on a fully assembled loco are not parallel, one face is tapered out at the bottom, there being a corresponding and counter tapered wedge hidden inside to make the bearing surface parallel.

Image3.jpg

In red are the fillets, guide faces and support structure of the hornguides, note tapered face to the right (front of loco) and lower fillets not in line with each other, the right being lower. The blue area is the tapered wedge to provide a parallel bearing surface, it is bolted to the tapered web on the right with the green bolt, this green bolt passes through a slotted hole in the red plate, the wedge rises up and down to take out any fore/aft slack the axle box may develop, the outer face of the axle box is marked in yellow. I have to confess my plate work is not as angled as the drawing suggests so any gap at the bottom will hopefully be hidden by a slightly wider than 1:1 axle box face ;) or I'll end up adding some scrap in there to make it look like a wedge affair. As I've opted for rigid chassis it won't be much of a drama.
 
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adrian

adrian

Flying Squad
Steve Cook said:
Not sure if it would have been easier, but rather than fiddle with the tiny fillets, I've read of a technique where you would make a cut through the hornguide bearing face (ie in the same plane as the axles, right down to the frame mounting face), right where you want a fillet to be.
Click to expand...
You mean like this?
http://www.westernthunder.co.uk/index.php?threads/casting-process-advice.3872/page-2#post-102852

I used half slots from either side to hold it all together before soldering.
 
OzzyO

OzzyO

Western Thunderer
Mick, could you make the fillets in a U shape and solder them to the horn cheeks? Down side it would make the horn cheeks a bit thicker than they should be but in the depths would you notice this too much?
Some nice looking work going on there.

OzzyO.

PS. how much of them will you see when the boiler is in place?
 
mickoo

mickoo

Western Thunderer
Ozzy,

I get ya :thumbs:, that could work, as the extra thickness to the horn guides/cheeks would be covered by the outer flange of the axle box. I'll try that as a trial on the next one.

How much will you see? No idea truth be told, Richard would be better able to answer that as he has a finished Finney one and could look 'inside' as see what can be seen. The trailing one I think will almost invisible from above but partially visible through the lightening holes, the intermediate will be seen quite a bit more and the leading should be easily visible at the right angle. I'll mock up a cardboard boiler tonight and see what I can see.

In reality you could just not bother, it's more an exercise of 'I am because I can' and if your going to add anything, then it may as well be as close to the right shape as you can. Having said that, I haven't gone to the trouble of adding for example the wedge nut or keep plate nuts, much the same as the reverser bracket fixings ( V shaped array of blobs between the leading and intermediate drivers at the top of the frame) are punched rivets but should be nuts in reality. If I can see these easily on the final loco I know it'll drive me barmy LOL, so the next one will have to have nuts! I already know the rear Cartazzi extensions have to come off as the shape behind the rear driver isn't quite right, and, I've punched very visible rivets which should be nuts. In fact on the next loco I'll probably go for a whole new set of frames, probably etched and correct for an A3 build and not an A1 rebuild which this one is.

The skill set will probably be more applicable when I get to the Britannia and 9F (though both of these have massive flat plate stretchers which virtually hide the hornguides) or other locos with more exposed frames. I certainly won't add them to the A4 or the Peppercorn A1 as those are almost totally invisible unless you turn the loco upside down or look up at from very low angles. In the latter viewing case then perhaps just the lower portion with keep plate and springs would be benificial visually.

I think the effect I'm more looking for are basic light blocking shapes rather than a totally void gap under the boiler or an exact copy of a real loco, something to suggest a 'busy' look under there. How much is really seen in the end is as yet undecided, but I'd rather add it now and not see it than have to add it all later.
Theres still the inner and outer sand boxes to fit and probably the inner slide bar, I may even go for the middle crank, but getting it in and out wih a rigid chassis is taxing zee leetle grey cells at the moment ;) I may slot the middle axle hole and drop it in and then solder the top hat bush when all done, or solder in a keep plate affair.

Of course making a middle crank is another whole new skill set to learn!
 
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OzzyO

OzzyO

Western Thunderer
Hello Mick,
when I did this lot for a F.R. Baltic (scratch build) I made the centre axle hole a key hole shape and made some top hats with a larger outer rim so that I could screw it in place using some 14 or 16BA counter sunk screws (two per bush).
valve gear.jpg
Them apart I think it was about two more screws and the valve gear came out.

OzzyO.
 
mickoo

mickoo

Western Thunderer
That's a neat idea :thumbs:

I can beef the frames up behind the top hat easily as it'll be covered by the axle box face and flange and can soon turn up a new bearing or modify one I already have with maybe a inner flange and maybe retaining screws underneath.

I need to at least get the new inner frame in on the drivers side and then look at some stretchers to make the frame more rigid, it's a bit 'flexible' at the moment and I need to sort a motor mount as well, I'm trying for a flat motor mount with flywheel but at the moment it's sticking through the cab face, no problem as I can cut that away inside the fire box and cover the protrusion in the cab with the back head.

The kit allows for a vertical fitting but I'm not comfortable with flywheels on vertical mounted motors, they tend to be noisy in one direction, if there's any end float then in one direction the motor tries to 'lift' the flywheel and thus generate noise, as well as appearing to require more power to get going in one direction. I.E to the left it moves off at 10% power setting, to the right it's 25%.
On the 08 it was horrible, but turning the motor to about 10-20° off the horizontal solved all that. Probably a placebo effect but it certainly seemed to help, the noise has certainly gone and skiming the weight true helped a lot with any vibration.

The other issue with the vertical motor is that it goes through the first section of the boiler, right through the area I've spent so much time opening up to get the correct daylight behind the wheels and frames! Plus, there's now a big hole in the bottom of the boiler...which will need to be filled, sigh ;)
 
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Steph Dale

Steph Dale

Western Thunderer
Mick,
Your ongoing references to cannon boxes has me intrigued. Does the prototype have them or is it a 'Mickism'? If the latter, can you explain why your taking that route; with a rigid chassis they're pretty much superfluous I'd think.
If you're putting the inside crank in I like the approach Paul has described. The bearing doesn't need to be retained though, the flange ('brim' of the top hat) will be trapped between the frames and the backs of the wheels when it's all assembled so nothing can drop out.
Steph
 
mickoo

mickoo

Western Thunderer
Steph, I thought cannon axle box was a standard term?, google throws up plenty of images and text to describe said item, having said that, it does seem a more popular term for enclosed axle boxes such as those fitted to BR roller bearing axles (Britannia, Std 5, BR Black fives etc) where the two axle boxes are joined together by a tubular spacer (splitable) which protects the inner bearing from grit between the frames etc.

So yeah, maybe some 'Mickism' involved, I'll go back and edit all the posts correctly. In defense I've been reading several detailed books on US steam locos (another simmering interest bubble) and the term had stuck in my mind and thought it a common term globally, on reflection all those locos I'm looking at have roller bearings and thus would have cannon boxes and not axle boxes, or more correctly.....I think, axles boxes joined with a cannon box? Is the cannon box the whole assembly, or the tube between the axle boxes, is the tube part of the axle box housing even, I.E cast as one part top and one part bottom? I fear another plunge down a rabbit hole looms ;).

I'm simply adding mine for visuals, at the moment all you can see is an axle going into an inverted U, it needs to have some sort of representation of the inner and top face of the axle box to make it look right.

Paul is right, his modification does not require a retainer because the top hat is it's self retained by the 'keyhole' and their own retaining screws to stop the top hat spinning in the frames. The only downside is that to remove the axle one has to pull off the wheels, that may be a problem if you have wheels fixed to the axles, tight clearances between motion and other plate work etc. It might be easier to change the intermediate crank pin from one screwed from the back of the driver and thus fixed, to one screwed from the front, therefore you only need undo the two crank pins and the whole axle and wheels can drop out easily, you can't do that with a keyhole slot so it'd have to be a full slot with a lower retainer with screws accessable from below, make sense? Or, just accept that once it's in, it's in, in which case you may as well just solder up the top hat once it's all in.
 
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Steph Dale

Steph Dale

Western Thunderer
Mick,

Okay, we're in violent agreement about the keyhole jobbie - I've not used screws to prevent rotation when I've done it - just soldered a piece of wire on the bearing. The trick, which you're picked up on, is getting all the cosmetic stuff (such as cosmetic springs) to fit round it easily so the axle can be fitted/removed.

A 'cannon' box is simply a tube which holds the outer parts of the bearings in alignment (i.e. it's shaped like and probably was originally made in the same way as a cannon!). It runs from the bearing on one side the whole way across the frames through to the bearing on the other side and is commonly used with roller bearings to preserve alignment and lateral load limits on the bearings. They are occasionally used with plain bearings where they're needed to preserve alignment in locos with articulated axleboxes, I can think of several examples in German practise and one I'm not to sure about in the UK - interestingly in a Gresley design (the P1s or P2s did have Krauss-Helmholtz front trucks didn't they?), which is why I was asking.

To add to the confusion there are split cannon boxes which is a refinement to ease servicing. The wear surfaces of a cannon box are on the outside, where they meet the axle guides (of whatever form - not necessarily 'hornguides') and so being able to remove them from the axle/bearings is useful.

I think what you're describing is a conventional split journal in the case of your A3, but you nailed the description in your last posting...:):thumbs:

Steph
 
mickoo

mickoo

Western Thunderer
Steph, agreed, some quick.....after the horse has bolted....refreshing zee leetle grey cells shows cannon boxes as you likewise describe, often associated with roller bearing axles. The main advantage with a cannon box is that it only has two lateral guide faces, as opposed to normal axle box set up which has four, I.E. two axle boxes, each with two lateral guide faces. The other advantage is the exclusion of debris from the bearings, especially useful for axles under fireboxes.

On the cannon box set up the bearings do not move on the axle and any lateral play is governed by the lateral guide faces of the cannon box I.E the box moves in unison with the wheels, on a traditional set up the axle box usually has no side play, but the axle inside does.

If y'all know this then apologies for the blatant egg sucking exercise ;) but the refresher is important to me, as I do need to model these when I do get to the Britannia and revisit the Std 5.

I knew these boxes were already fitted to Britannias and Std 5's as well as the later BR Black fives, they're also fitted to Tornado, which I don't think the originals had on the drivers. They are also fitted to C&O Alleghenys, N&W Y6b (I really must order the GA's and detailed diagrams from them soon) , UP Challengers, Big Boys and SAR 25NC (drawings already acquired)

Cannon axle box.jpg

These are Britannia cannon boxes, copyright with original owner.

Of note, the bogie one has outside lateral guide faces, the drivers have inner lateral guide faces, both are formed of one complete casting, which includes the cannon and axle box, I've not seen any that are split into three, I.E. the tube and two axle boxes, but, do accept there may well be cases of such that I know nothing about.

In the instance above, the bearings are inserted from the outside and retained by a cover plate who's bolt heads can be seen on the rear face of the bearing casing.

It'd be interesting to see how Tornado uses this set up with an inside crank, I assume there will be two 'half' cannon boxes each side of the crank webs?

My mistake was assuming canon box was a generic term.

Regarding keyhole bearing installation, no violence intended? I accept there are many methods to achieve the same result, most down to personal preference :cool: you use a wire strap, Ozzy uses countersunk screws, me? I've not used anything yet, but all options are being considered :thumbs:

I'd actually forgotten about the springs and hangers underneath, they'll be a PITA to take on and off, unless fitted to some sort of removable bracket, I'll mull this all over as I progress other sundries ;)
 
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mickoo

mickoo

Western Thunderer
Just before I closed and returned my C&O book to the shelf I came across this war time propaganda photo, a cracking shot showing a split cannon box and it's bearings, I'm not sure exactly which loco this fits but it looks like they may fit the K4 Berkshires.

Image1.jpg

This is a crop and copyright exists with C&O
 
Steph Dale

Steph Dale

Western Thunderer
mickoo said:
I'd actually forgotten about the springs and hangers underneath, they'll be a PITA to take on and off, unless fitted to some sort of removable bracket, I'll mull this all over as I progress other sundries ;)
Click to expand...

Fit them to the bearing - it'll also stop the bearing turning in the frames...

Steph
 
Dikitriki

Dikitriki

Flying Squad
Hi Mick,

I have had to face this problem with inside valve gear locos, and since I normally use brass castings for springs, I find a location where I can use countersunk screws thus:

AspinallAsprings.jpg

This is my Aspinall A. The screws will be blackened and I try to locate them so they are hidden behind the tyre where they are pretty invisible. They also serve the purpose of retaining the hornblock.

Regards,

Richard
 
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