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Annie

An Interesting Variation on a Terrier.

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Seaforth in 'O' would certainly keep me happy.

 

L85vxSD.jpg

 

 

 

 

 

I have a suggestion for the 4mm version.

 

The driving wheel diameter is 5'6". 

 

The driving wheel diameter for another small tank prototype is the LSWR 298 Class, Beattie well tank, is 5'7".  On the Kernow model, it is the central axle or lead driver that is geared.  Given that Kernow chose to represent the class in modern times (from 1935), I suspect this rebuilt form will have a higher pitched boiler than originally, and the Kernow might not fit Seaford's profile, but it might be worth a look.

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Trouble is, the beattie is a bit pricey! If I bought one I would be attempting to backdate it, or even leave it as it is, but not use it as a chassis donor!

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Trouble is, the beattie is a bit pricey! If I bought one I would be attempting to backdate it, or even leave it as it is, but not use it as a chassis donor!

 

It is, and being a retail commission, it never gets decently discounted (and it's not that great a model for the price).  I had a plan to use the chassis of one to build a GER No.1 Class 2-4-0.  When I added up the cost of all the castings etc I needed to the high price of the RTR Well Tank, I realised that it would be cheaper to buy the wheels, motor, gears etc and the Peter K kit.

 

To be frank, to consider such a prototype, I'd want to master building a motorised chassis.

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The driving wheel diameter for another small tank prototype is the LSWR 298 Class, Beattie well tank, is 5'7".  On the Kernow model, it is the central axle or lead driver that is geared.  Given that Kernow chose to represent the class in modern times (from 1935), I suspect this rebuilt form will have a higher pitched boiler than originally, and the Kernow might not fit Seaford's profile, but it might be worth a look.

Can I suggest that on a single driver you really, really want to have a compensated chassis. Otherwise you can find yourself with the driving wheel spinning gently in the breeze.....

Best wishes 

Eric

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Can I suggest that on a single driver you really, really want to have a compensated chassis. Otherwise you can find yourself with the driving wheel spinning gently in the breeze.....

Best wishes 

Eric

 

As good a reason for not attempting a Single as I have heard!

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Oh great!

 

Now I need to work out compensated 3D printed chassis!

Edited by sem34090

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With smaller Drivers, Seaford would not be a huge departure from 'milford'

Edit: whilst were on the topic of single driver tank locos, converted Sharpies, saddle or well tanks, are quite pleasing

post-29975-0-48442300-1520278949_thumb.jpg

post-29975-0-61714900-1520289720_thumb.jpg

post-29975-0-95668900-1520289731_thumb.jpg

post-29975-0-65990500-1520289739.jpg

Edited by Killian keane
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All these lovely pictures of single driver tank engines   :heart_mini:  :heart_mini:  :wub:

 

A trick with single driver locomotives is to drive the two outer axles and leave the big wheel to idle along.  Or set the chassis up so it has a pony truck at the front and the model rests on the centre and rear axles.  I remember Mike Sharman discussing such things in RM hundreds of years ago when I was but a young slip of a girl.

 

A gratuitous drawing of a Sharpie well tank just because.

raDHzd9.jpg

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People better be careful what they wish for. We are currently working on the Furness or more correctly Sharp Bros/Sharp Stewart 2-2-2WT in 7mm. We might have the prototype ready for the NEC. Along with a 2-4-2T and 2-4-0.

 

Marc

My only concern if you excuse me saying so Marc is that I might have to sell a kidney to buy one.  ueOQWcg.gif

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To be perfectly honest I am not sure. The holes are 3mm in diameter, so what that is in inches I couldn't tell you, unfortunately, as although I work in feet and inches for large things (Baseboards, Full scale CAD models, etc) I work in mm for small scale stuff, including chassis (I work these out after scaling a model down.).

 

In truth, I have yet to build a chassis in the real world, but appreciated from the outset that some wouldn't be happy with the compromises incurred with an RTR chassis. I myself don't mind, but I know some people do.

 

Please forgive me but I am a little bit confused with this reply, reading it I get the impression that this chassis has not been tested as there is no mention of which wheels it has been designed for, no real issues with certain compromises providing the chassis works

 

Most 4 mm wheel suppliers use 1/8th  (3.17 mm) axles, for me 3 mm would not be an issue as I could use a parallel 1/8 reamer. However this causes another issue, with any chassis made from soft material, including thin walled brass sheet a top hat brass bearing is used. The thin part of the bearing has an OD of 3,7 mm and the wider part which extends on the outside the frames by about 1mm.

Photo of a top hat bearing

https://www.google.co.uk/search?q=Brass+model+railway+1/8+bearings&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjSrp-Em9fZAhVMJcAKHUn2AusQ_AUICygC&biw=1366&bih=637#imgrc=1Mg3ZihdxD4OzM:

 

There is one company which sells 3 mm axles (used on converting RTR chassis). My one concern is the longevity of the chassis without any form of hardened bearings. 

 

As for compensation of the wheels mentioned in a later reply, the normal way of doing it is to use hornblocks (a form of bearing which slides up and down in/on a plastic hornguide or brass plate or guide)

 

Link to Brassmasters web page on hornblocks

http://www.clag.org.uk/brassmaster.html

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A gratuitous drawing of a Sharpie well tank just because.

raDHzd9.jpg

 

There is already a thread about building one of those!

post-9472-0-57873900-1520327376_thumb.jpg

Come on: some one else have a go!

Best wishes 

Eric 

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Please forgive me but I am a little bit confused with this reply, reading it I get the impression that this chassis has not been tested as there is no mention of which wheels it has been designed for, no real issues with certain compromises providing the chassis works

 

Most 4 mm wheel suppliers use 1/8th  (3.17 mm) axles, for me 3 mm would not be an issue as I could use a parallel 1/8 reamer. However this causes another issue, with any chassis made from soft material, including thin walled brass sheet a top hat brass bearing is used. The thin part of the bearing has an OD of 3,7 mm and the wider part which extends on the outside the frames by about 1mm.

Photo of a top hat bearing

https://www.google.co.uk/search?q=Brass+model+railway+1/8+bearings&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjSrp-Em9fZAhVMJcAKHUn2AusQ_AUICygC&biw=1366&bih=637#imgrc=1Mg3ZihdxD4OzM:

 

There is one company which sells 3 mm axles (used on converting RTR chassis). My one concern is the longevity of the chassis without any form of hardened bearings. 

 

As for compensation of the wheels mentioned in a later reply, the normal way of doing it is to use hornblocks (a form of bearing which slides up and down in/on a plastic hornguide or brass plate or guide)

 

Link to Brassmasters web page on hornblocks

http://www.clag.org.uk/brassmaster.html

You are indeed correct in that the chassis has yet to be tested, and as such I will need to go back and check a few things. Unfortunately all CAD progress has stalled for now due to the memory stick it was all saved on giving up the ghost.

Any recommendations that you offer will be put into practice at the next possible opportunity.

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I would imaging that the material used in the chassis could wear over time so provision to fit a standard 1/8th inside diameter brass bearing would be wise and also give the builder a wider choice of wheels, perhaps designing the chassis to use either the Alan Gibson or Markits units. Happy to chat this through with you, though there are far more accomplished loco builders on this forum.

 

As for having some form of suspension unit for the drivers, I think you would have to buy a hornblock set and see how these could be fixed in place perhaps within a rebated area

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That would be very much appreciated!

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