Stanier 8F in S7

[DavidinAus]

I have my name on the list for a 9F.

Being new to railway modelling , I really shouldn't even think about S7 but looking at MOK & MMP kits I feel that S7 is the gauge these kits deserve.

Now where is the S7 Group membership form.

Dave

I was new to modelling (well not quite, but I hadn't done any modelling for 30 years) when I came to 7mm scale. After just a short while with FS, I changed to S7 and have never regretted it or looked back. It's easier in some ways, as "eastsidepilot" says: if it fits in the prototype, you know it must fit in S7 (just a little smaller). I've had a couple of articles accepted for publication about my efforts on the second and third loco.s I have ever made in 1:43, in which I hoped to show that if I can do it, anyone can!

Support Dave Sharp - he's doing a good job for S7. A pioneer. I hope that if we can make this work, more will follow.

David C

 

[SteadyRed]

Support Dave Sharp - he's doing a good job for S7. A pioneer. I hope that if we can make this work, more will follow.

David C

I couldn't agree more, I live in Lincoln, not a million miles from Dave Sharp & it was his standard 4MT tank which I saw part build at a Lincolnshire Poacher Group meeting, got me interested in 7mm.

Dave

 

[Wagonman]

I was new to modelling (well not quite, but I hadn't done any modelling for 30 years) when I came to 7mm scale. After just a short while with FS, I changed to S7 and have never regretted it or looked back. It's easier in some ways, as "eastsidepilot" says: if it fits in the prototype, you know it must fit in S7 (just a little smaller). I've had a couple of articles accepted for publication about my efforts on the second and third loco.s I have ever made in 1:43, in which I hoped to show that if I can do it, anyone can!

Support Dave Sharp - he's doing a good job for S7. A pioneer. I hope that if we can make this work, more will follow.

David C

You may be interested to know that there is a groundswell within the S7 Group committee to the effect that an 8F driver should be next on the list of wheels to be produced by the Group. Watch this space...


Richard

 

[OzzyO]

Hope that Dave does the same for the 9F.
SimonT

The 9F has narrow frames to start with in real life so why make them wider?

OzzyO.

PS, IIRC, the 8F had thinner flanges on the middle two wheel sets.

 

[DavidinAus]

Damn. I've just bought a set of 8F wheels from Slaters. I wish that I had known.

David

 

[adrian]

PS, IIRC, the 8F had thinner flanges on the middle two wheel sets.

Piqued by this comment I dug out the Wild Swan 8F Profile book.

Your recollection that there were thinner flanges appears to be correct but they were on the leading and trailing axles and not the middle ones. Page 68 second paragraph says

Along with most other six- and eight coupled LMS locomotives , the 8Fs were the subjects of instructions issued in July 1940 aimed at increasing the side play on the leading and trailing coupled wheels. [...] Job No. 5171 was issued for the machining 1/8" from the inside faces of leading and trailing coupled wheels as well as from the axles at the outside of the journals.

So my reading of this is that the leading and trailing wheels had 1/8" shaved off their flanges but the axles were narrowed as well, so the wheel back to back is maintained but the width over the flanges is reduced by 1/4" on the front and rear wheel set.

So I'll make sure that I shave 3 thou off the front and rear wheel set and reduce those axles by 6 thou!

 

[Overseer]

Piqued by this comment....

So my reading of this is that the leading and trailing wheels had 1/8" shaved off their flanges but the axles were narrowed as well, so the wheel back to back is maintained but the width over the flanges is reduced by 1/4" on the front and rear wheel set.

So I'll make sure that I shave 3 thou off the front and rear wheel set and reduce those axles by 6 thou!

I would read that differently- the inside of the flange would be the side adjacent to the running surface so facing outward on an assembled wheel set, the back to back would not be altered. They also turned or faced off a bit from the back of the wheel adjacent to the axle so there is more space between the bearing and back of the wheel to allow the axle to slide sideways (without any control) to ease rounding corners. So you would thin the flange from the outside (of the axle) and probably thin the bearing slightly to achieve the same aim on a model, or use a thinner shim washer. I have drawings somewhere of a different prototype showing similar narrow flanges.

 

[OzzyO]

Piqued by this comment I dug out the Wild Swan 8F Profile book.

Your recollection that there were thinner flanges appears to be correct but they were on the leading and trailing axles and not the middle ones. Page 68 second paragraph says


So my reading of this is that the leading and trailing wheels had 1/8" shaved off their flanges but the axles were narrowed as well, so the wheel back to back is maintained but the width over the flanges is reduced by 1/4" on the front and rear wheel set.

Think about it. you take 1/8" off both wheels = 1/4" then take off 1/8" off each end of the axles 1/4", that to me = 1/2" Narrow.

So I'll make sure that I shave 3 thou off the front and rear wheel set and reduce those axles by 6 thou!

When you read the it correctly, it says off the inside face of the wheel, that implies the part of the wheel that runs against the axle box. Not the back of the flange. The wheel is the casting that has the tyre fitted to it. It sound more like that you end up with 1/2" side ways ply on the front and rear wheels without having to touch the middle flanges. I may have been thinking about the star fitted 8Fs when I said about the thinner flanges.

We as model makers, make a lot of the B-B of wheels but on the real railway the important dimension is the back of flange to root of flange dimension.

OzzyO.

PS. well done the boys in red.

 

[adrian]

Agreed, to be precise, it does say wheel and not flange, but how that is implemented maybe is open to interpretation. I wouldn't like to say how the guys on the shop floor took that instruction.

However given that the tolerance on the S7 back to back and flange width is 4thou I'm not going to loose any sleep over the matter. I think I can live with the one wheelset to cover all 4 axles for my model and I'll not get too worked up if anyone tells me I've got it wrong.

 

[OzzyO]

You will always get the bloke that has the Hubble telescope eye and will say that you "have got a L/H mangelwert gromt" and it should be a "R/H mangelwert gromit" Then when you ask him, how may models have you made or a photo of one. They shut up.

Adrian, lets just do what we do and do well and enjoy.
That sound bad, hope you know what I saying!

ATB

Paul.

 

[DavidinAus]

... and to think that I am concerned about what happens to the spoke-to-rim measurement when Slaters wheels are reprofiled to S7 thickness ...

David

 

[JimG]

Seems like they were doing the same back in Caledonian days - the tyre specs for the Caledonian dock tank with a thinner tyre and flange shown for the centre, driving wheel. There seems to have been some question about the back-to-back measurement.





Jim.

 

[alcazar]

You will always get the bloke that has the Hubble telescope eye and will say that you "have got a L/H mangelwert gromt" and it should be a "R/H mangelwert gromit" Then when you ask him, how may models have you made or a photo of one. They shut up.


Paul.

What if it's Ken off RMWeb...and he produces a HUGE book...........?

 

[S7BcSR]

Don't forget that there were many variations on the BS276 standard for wheels, a number of which were for tyres with thinner flanges and also wheels without flanges (e.g. 9F). For modelling purposes, in general, one standard was chosen to suit all wheels. In the ScaleSeven world BS276A was chosen as the wheel standard at the time of setting up the S7 Group (see the standards on the S7 website) and I believe that it was this standard that was chosen for P4 back in the '60s and subsequently for S4. The variations are generally so small as to not really matter in the smaller scales.

Now to what does really matter is that we all have the same central hub size for all driving wheels whereas many locos had a considerably larger hub on the wheel where the connecting rod was fitted but do we model it. Very rarely and yet it is more visible than the flange profile changes.

Rob

 

[SimonT]

The 9F has narrow frames to start with in real life so why make them wider?

Good job that I had talked to Dave about building my 9F to S7 and not mentioned the frame width. Oh no, I have!!

 

[Dog Star]

That's why we produce three different 6' 8" GWR drivers, for instance.

I regret failing to convince David White that we needed four versions... just look at a Saint in early condition and then a Saint after about 10 years of running.

regards, Graham

 

[OzzyO]

I regret failing to convince David White that we needed four versions... just look at a Saint in early condition and then a Saint after about 10 years of running.

regards, Graham

Is this what your thinking of the two wheel boss sizes?


OzzyO.

 

[Dog Star]

Is this what your thinking of the two wheel boss sizes?

Exactly... from study of Saint photos I have come to the conclusion that the "larger" boss was first found on the driving axle with the occasional, later, occurence on the leading axle. This scenario can be seen in Paul's photo of Saint David - even though such an engine survived into BR days that was not enough to get the extra style of wheel.

I do not recall reading any explanation of this variation in wheels for the Saints... my best guess is that the original and smaller boss could not take the stress from the force on the 18" pistons so the boss was enlarged to increase the interference fit of wheel on axle... and to allow for the "ace in the hole" of the huge keyway. Why did the Stars not suffer? Probably because the Stars had 16" pistons and divided drive.

Yes, maybe I ought to get out more... however the early years of Churchward's reign are such a rich vein of engineering interest.

 

[DavidinAus]

In helping Dave Sharp with the production of the custom etch for ScaleSeven, he has sent me a pre-production etch, and is asking me to try building with it.
So far it seems excellent, as you might expect from MOK.
Here are a couple of pictures:

First shows the frame spacers attached only on one side


The second shows the frames together:


The tab-and-slot construction works so well ....
It's easily the best kit I have worked with yet.

David

 

[markjj]

Has anyone got a set of the 8f S7 additional etches? I contacted Dave at MOK yesterday to obtain a set but he hadn't got any stock for 3 weeks... I'm in the process of building up my 8F's but I need to know which etches have changed so if anyone has a set could they possibly put up a few pictures of an untouched set...
Thank you

Mark J