My 7mm dabblings

[7mmMick]

Fantastic work Mick. All is now clear, it's a good way of cutting parts out if you have instant access to CAD and are proficient in its use. It's definitely something I would like to get into when I have more time. I keep promising myself a CAD package and some training time, it will happen..... Std 5 looks great and as you say some of the lines of the smokebox/frame gap on the real thing are shocking so yours looks great. A very enjoyable thread an certainly one I'll refer to
In the future. It's a shame I'm working this weekend as I'd like to see them in the flesh at WMHQ but it will be the new year when I get down,

ATB Mick

 

[Len Cattley]

Hi Mick those photo's are great lets hope that one is being repaired near one of us , looks like you would have to live near it as it would take a long time to see it finished.

Len

 

[mickoo]

And now with boiler, just tacked onto the firebox for alignment testing and the smokebox is just pushed on, it all just about fits and lines up and'll only need some minor tweaks to the mounting bolts/holes to let it all settle down nicely.

Next step may be some front footplate and buffer platework. In reality I need to tackle the firebox shoulders and their radii, I've been putting that off for months now but like the taper boiler will probably not be the chore I'm dreading, it'll be a slowly slowly catchy monkey process though LOL

The cab base needs some fillets adding to make good the holes where the firebox goes in under the cab and hopefully some more of plate work for the rear buffer beam before Sunday's meet.







Sorry for the drop in photo quality, big bess is at work during the week so it's back to the handy cam I'm afraid.

 

[mickoo]

And now with wheels

Tried something different here, CSB in as basic a format as I could, no fancy hornblocks guides or what ever, just slots and top hat bearings, whether it'll stand the test of time will be another matter but thus far it ticks all the boxes in that there's little side play, up and down movement is free, it's simple and it's cheap.

First task is to stick the bearings to a piece of 25 thou brass with double sided tape.


Next stick in vice and file a slot where you want the CSB tube to go


Apply tube in one whole length and solder profusely




Cut each individual bearing off and retain as much of the tube as you wish, I kept as much as possible working on the theory that the tube will just touch the inside of the frames and stop the bearing moving out, in hindsight there's no need as side play is determined by frame spacing and wheels/top hat bearing flange.


I've opted for under slung as over slung will be seen through the large slots at the top of the axleboxes on the 1:1 frames. In theory the longer CSB tubes at the base of the top hat bearing should stop it rotating, it'll rotate a little but not round and round.





Seems to sit right and rock in all the right places, I may need to fiddle with the position of the intermediate tubes to get the balance right as at the moment it's best guess. On the 08 I followed the spreadsheets and found the loco still rocked about the centre axle (even though it was 10% less than those either side) so ended up moving the intermediate fixings to suit by reducing the % load on the intermediate axle even more.

I finally did the firebox shoulders, initially dreading the very large radius I'd seen in photos, however before taking the plunge I decided to visit the image store once more and noticed a loco whose shoulder radius was virtually non existent, very Fowler square style radiused corners, further investigation reveals two major types of sheet metal work on the firebox shoulders, those with very large radius and those with virtually none, there is a third which seems sort of between the two but edging more toward the smaller radius. I've no idea why there are differing types, a quick look at other BR types find them all to be the same through out the class...which ever style they have. It's not just one or two locos either, I've over 40 photos of the smaller sharper radius fireboxes....of course I've opted for one of these, which means in due course there will be much finger pointing by those that proclaim to know better


F105-022 by vsidlow, on Flickr


F040-148 by vsidlow, on Flickr

Above has the small radius firebox shoulder as compared to below with the large


It would appear that you stand a higher % of having the smaller radii if it's a Southern or Scottish loco but I've seen locos at Crewe/WCML and York with the smaller Radii. On hindsight I've probably added to much radius to mine so it's more toward the intermediate style.

 

[Heather Kay]

I'd give Slater's a call on Monday morning and see what they say. If you ask nicely they may swap the set out, even though they've been opened.

 

[Overseer]

Mick

PB = pin between, IL = in line, as in the relationship of the crank pin to the spokes.

It would be very useful if Slaters would put photographs of their wheels online, especially for those of us who build models of non British locos as well.

 

[mickoo]

I'd give Slater's a call on Monday morning and see what they say. If you ask nicely they may swap the set out, even though they've been opened.

I've sent a grovelling email to explore the possibilities of an exchange for a fee if required, I hope they can accommodate in some way, failing that, it's an expensive mistake as it's not as though I can use them elsewhere for foreseeable projects. In fact I'm trying hard to think of any locos with webbed crank spokes in BR times, if I could find one that fitted my interest I'd keep them for a later date scratch build.

Mick

PB = pin between, IL = in line, as in the relationship of the crank pin to the spokes.

It would be very useful if Slaters would put photographs of their wheels online, especially for those of us who build models of non British locos as well.

Thanks, you must have posted as I edited LOL

I'd Googled and found the answer in another supplier of 4mm wheel descriptions all places and edited the above after I'd found the answer.

Photos would be good, or, even half accurate descriptions, I've looked at the rest of the wheels and it's ok if they quote specific locos as you can go and research those, but those that do not are buyer beware as you've no real idea what your getting I'm sure they are very helpful if contacted and will answer all questions accurately, it'd just be nice if you could glance down the list and see without recourse to bothering them with fundamental questions as to some basics about the wheel.

 

[SimonT]

Mick,
join the club. I discovered that I had ordered the wrong wheels, after profiling to S7, when the con rods clouted the outside brake rods during final assembly. DOH!

The CBS looks very interesting. At the risk of missing an earlier post, what size wire do you use and what is the target weight of the finished loco? Cracking build.

Simon

 

[Steph Dale]

Mick,
Two quick thoughts:
For a Fowler loco shouldn't you have plain rather than vee rims?
You are no doubt aware that replacing the CSB pivot points with lengths of tube materially affects the weightloading and spring compression rates of the wires? Effectively it will close up the spacings through the centre of the chassis; the loco will end up resting heavily on its centre driver rather than the end ones. You may get some peculiar running as a result!
Steph

 

[mickoo]

Mick,
join the club. I discovered that I had ordered the wrong wheels, after profiling to S7, when the con rods clouted the outside brake rods during final assembly. DOH!

The CBS looks very interesting. At the risk of missing an earlier post, what size wire do you use and what is the target weight of the finished loco? Cracking build.

Simon

Simon, it's .020 spring wire (0.51mm) and the tubes are 1mm ID, thus the wire is a very sloppy fit but the larger tubes do allow you to go up in wire size if I end up with too much deflection, currently looking at roughly 1-1.5Kg loco weight and a 1 to 1.5mm deflection fully loaded, very soft I'm told.

 

[Dog Star]

Mick,
Unless I am mistaken, each Slater's wheel is based upon a prototype, somewhere. If you ask David White he is likely to provide that information.

 

[Steph Dale]

Mick,
You're comparing modern monoblock wheels (with the tyre attached as part of the wheel) as against built up wheels for steam locos. You're right that the former have a turning mark for re-profiling, indicating the point at which the wheel must be scrapped. For the latter the turning limit is usually in the region of 3" and indicates the point at which the tyre is likely to fail and so the tyre must be replaced; I guess your estimate of 4" (with a very thin tyre) might be about right for a tyre right on its scrapping limit.
I have a thread running on here about refining Slater's wheels, which involves cutting the back out of the wheel http://www.westernthunder.co.uk/index.php?threads/refining-slaters-wheels.1925/page-3.
As you say, most of Slater's wheels are nicely formed on their fronts, so they're frequently worth re-working.
Steph

 

[Len Cattley]

Hi Mick I wouldn't guarantee in slaters knowing that they would be correct on what wheels these were for as they didn't get the correct spokes for the Princess's.

Len

 

[SimonT]

Simon, it's .020 spring wire (0.51mm) and the tubes are 1mm ID, thus the wire is a very sloppy fit

Thanks Mick, I have a David Andrews 52XX on the bench at the moment and fancy doing something other than the usual individual sprung horn blocks.

I agree it flies in the face of S7 but my objective is a smooth running loco

As long as it works and runs beautifully, looks spot on and makes you happy then, as a S7 modeller of 20 odd years I think it hits the S7 ethos. But then I am known to be heretical in such maters - S7 diesels than can be converted back to finescale, current batch of steam engines ditto.

Simon

 

[SimonT]

The beauty of the 52XX is that you cannot see into the space between the frames!

 

[Scale7JB]

I'll admit, I do like the idea you've had though I didn't get a chance to see it yesterday.. Something I might well try in future with the B17 and/or B2.

JB.

 

[mickoo]

Small update visually but a lot of work to fabricate and if I'm honest, not overly happy with some aspects, it's been close to being drop kicked over the garden fence a couple of times! Problem is to fix the faults will need a whole new running plate and front drop valance, I may just end up picking the valance off and doing a new one but the footplate will have to be.....discretely weathered 'bodged' to hide the faults. I did um and ah about adding the small inner kick fence to the running boards, fiendishly awkward to accomplish but the over all effect from something so small far outweighs the pain to achieve the result. Despite all the issues, it is amazingly...!! straight, level and parallel in all the areas it's supposed to be

Still some odd little bits and bobs to do to this side before moving to the drivers side, hopefully that one won't take three weeks like this one did! The interest bubble deserted me on several occasions and I only kept going due to sheer ignorance and bloody mindedness LOL



Might try and take some better photos like with the big 'un' rather than the point and shooty pocket rocket camera tomorrow.

 

[Len Cattley]

Still looking good Mick

Len

 

[mickoo]

Couple of coffee's and a round of honey on toast and a revisit to the front valance....it had to come off....really it did, it'd only been on a few hours and it was annoying the out of me already.

On the left the new one, on the right the original, not a lot of difference you might think, the original one had the rivets punched first and then the panel lines scrawked on which obviously didn't go straight, this time the panel lines were done first and then the rivets punched from behind, which can.....and has led to some of them not being perfectly in line above and below the scribe, even though the compound table was used on the rivet press. What isn't obvious on the original is where the scrawker slipped off line on the lower left panel line, and scratched a nice gouge in the brass, which due to the rivets could not be sanded smooth of filled and sanded effectively.

I also took the liberty of adding in the vertical lines of rivets missing off the original, and as yet, have to add the two clusters of triple rivets near where the hand holds will go on the front platform. I'll sleep on this and....may even do it again, to get the rivets perfect above and below the panel lines now that I have a better template to work from. The original I'd give a generous 6/10, the newer a tentative 8½/10.

 

[mickoo]

Time for a little change in era and to drag another interest bubble to the fore, the Std 5 is at a position where it can be put into warm storage for a brief hiatus like the Fowler 4P and 08.

Finally managed to get the last measurements from the 1:1 loco this week so that the cab can started, at the moment it's just CAD to paper etch to test angles and dimensions, the cab roof shape looks simple but is far from it, the angles and panel sizes vary and the cab tapers to boot, getting all the dimensions correct so that the cab is square and tapered in the all right places is quite difficult. Next stage is a cab rear bulkhead to ensure the cab rear is formed to the correct shape and a dummy cab front bulkhead former to make sure the roof profile is correct.

Then it'll be back to CAD and begin work on the other detail parts like windscreens, horn cowl, front valance and light cluster housings, this'll then be sent to the etches for Nickle Silver kit format. The rest will follow once I'm happy the cab area is correct.

In the flat


Folded up




The critical part is ensuring the cab roof peak is perfectly parallel with the cab base, I.E doesn't tip up or down at one end. Windows are just rough holes to give a better idea of shape and form.