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Choosing a 7mm standard?





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#1 PL8180RM

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Posted 11 September 2017 - 14:18

In the past I out together a simple Jim mcgeown 0-4-0 and a few freight wagons in ScaleSeven, and build a nice long point for them to run over. I didn't pursue any further but now I'm thinking about getting a slightly larger kit as a long term project and need to consider my options.

I'm looking at the DJH LNER A3 and really wondering whether S7 is a good choice - I'm not clear how strong the society is, I can't seem to find anyone to reprofile commercially available wheels and I'm sure that the valve gear is going to be hard enough without worrying about even tighter clearance.

If it doesn't sit entirely on my shelf then it MAY feature on a small shelf layout in my garden office (maybe representing the buffer stops of a larger terminus). I don't think I'll be taking it to meet and greets or shared layouts.

Any thoughts would be greatly appreciated.

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#2 ROSSPOP

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Posted 11 September 2017 - 14:31

Hi PL......

 

I would suggest joining the Western Thunder Forum as well......... you will more likely find a link to your  S7 wheel reprofiling enquiries  there.

 

I`m 7mm finescale even though I was formerly 4mm P4. I find that Slaters finescale wheel profiles more than adequate in the `looks right` department without the extra work moving wheel splashers and smokebox bases when the majority of larger 7mm locos are designed for  32mm gauge.

 

Cheers John.



#3 ian@stenochs

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Posted 11 September 2017 - 15:08

Hi Pl.

S7 is certainly viable for big locos and there is a difference between standard 0 and S7 wheels. I moved from P4 to 0 but quickly converted to S7 because of the too narrow frames and distortions required by the narrower gauge. There may only be 1 mm in the gauge but the much narrower back to back of 0 is the problem.
I mostly scratch build but have converted kits and have a Royal Scot, black 5 and WD 2-8-0 among the bigger engines. All with no real clearance problems in the valvegear. It's just a case of working to prototype dimensions and cutting out slop in bearings.
There are a number of commercial undertakings who will reprofile or supply wheels to S7 standards. The S7 group also sell form tools if you have acces to a lathe. They also do a growing range of dedicated wheels, mostly made by a Slaters, but far superior to the 0 gauge version, with proper 3D spoke shape on the newer ones too.

Come on give it a go!

Ian.
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#4 PL8180RM

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Posted 11 September 2017 - 15:26

Thanks Ian, I did give it a go before but a piddly 0-4-0 is quite a different prospect to a 4-6-2 beast. I agree with your sentiments entirely on the look. Can you elaborate a bit more about the slop? As per John's mention on moving wheel splashers, that doesn't to be with confidence if it's going to be repeated a dozen times all over the model!

Thanks too to Rosspop, I've joined the firm and found a cheap building the same kit. Is it all S7 or is there just good representation there?

#5 PL8180RM

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Posted 11 September 2017 - 16:22

Also just had a massive brainwave that the attic in the house I'm buying is both finished and unclaimed by spousal authorities. Maybe a spot for a Pacific to stretch it's legs, assuming it would fit around the radius required:

https://i.imgur.com/H3AQDHy.png

This is the vendors picture, the Alex is only about 7' tall and around 20' deep from where the photo is taken, another 5' behind. Maybe 6 or 7' in width where the crossbeams sit?

#6 Kubes

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Posted 11 September 2017 - 16:31

I suspect a pacific in S7 would struggle with radii under 6ft. As in all modelling you have to choose where you are going to compromise.
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#7 PL8180RM

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Posted 11 September 2017 - 16:46

Understood, after a small bit of investigation it would appear around 7' is the minimum.

I'm very much oriented around a single display model that COULD run, so I think it'll have to be a modular out and back, possibly as a slice of a larger station. If it were modular I could think about exhibiting. I do have a local club who are broadly supportive but with no current 7mm scale projects.

#8 ozzyo

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Posted 11 September 2017 - 22:24

 
https://i.imgur.com/H3AQDHy.png

This is the vendors picture, the Alex is only about 7' tall and around 20' deep from where the photo is taken, another 5' behind. Maybe 6 or 7' in width where the crossbeams sit?

 

That photo is on a house selling site, it looks more like a tip or a bomb site.



#9 PL8180RM

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Posted 12 September 2017 - 11:56

Building survey picture before they move out :)

#10 Western Star

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Posted 12 September 2017 - 16:48

I'm looking at the DJH LNER A3 and really wondering whether S7 is a good choice - I'm not clear how strong the society is, I can't seem to find anyone to reprofile commercially available wheels and I'm sure that the valve gear is going to be hard enough without worrying about even tighter clearance.

Some of the members of the S7 Group offer a re-profling service for wheels...  for example:-  "East Side Pilot" on Western Thunder provides such a service.

 

The S7 Group Stores has a range of pony, bogie and driving wheels made - to S7 standards - by Slaters.  At the moment there are about eighteen different wheels in the range and the sizes have been chosen to reflect the more common sizes found on the prototype railway.  In addition to the wheels for steam locomotives the S7 Group has just introduced a 3'9" wheel for the Brush Type 4 in response to the release of the JLTRT Class 47 kit.

 

S7 wheels for 33mm gauge have a greater back to back measurement than 0-FS wheels for 32mm gauge - this does not mean that the S7 wheels are wider (over front of the tyre / boss) than 0-FS wheels for a S7 wheel is produced as a scale representation of the prototype and often that results in a S7 wheelset which is comparable in width to the corresponding 0-FS wheelset.  Hence...  moving to S7 does not necessarily mean greater chance of problems with valve gear.  My Son has built the Finney A4 to S7 and there is clearance generally in the motion - with the exception of the leading crank pin "nut" which on the prototype is recessed into the coupling rod so tight clearances anyway.

 

regards, Graham


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#11 PL8180RM

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Posted 13 September 2017 - 05:58

Thanks Graham! I gather I'll want to widen the chassis possibly?

I hear good things about Finney kits and I'm lead to believe there is an A3 one coming soon.







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