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12mm gauge loco chassis width


Baldwin30762
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Hi all I am after a bit of advice, I am about to build a number of Isle of Man Railway 2-4-0T in 00n3 but I have been told by various friends that the chassis kit from Branchlines is a bit too wide, so I am looking for the ideal width of a brass chassis in 12mm gauge that will allow for a bit of movement in the back to back.

 

I hope to leave a bit of slack width wise in the chassis to allow for a little bit of wiggle room, I was just wondering if there is an Ideal width for a 12mm gauge chassis any suggestions would be welcome.

 

 

Colin     

Edited by Baldwin30762
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I recall the back-back measurement in 12mm gauge is 10.5mm and the old Triang chassis were about 9mm wide [i have sold all mine]. If you set the bearing bushes to no more than 9.5mm width you'd have 0.5mm each side for play and current collectors if required. Or just go for 9mm and use a washer each side as a spacer if need be.

 

Hope this helps.

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My own experience is 14.2mm gauge, but I do have a couple of 12mm gauge chasses. These seem to use spacers between the frames of about 8.5mm. Each frame is 0.4mm so width over the frames is 9.3mm. Then if you use top hat bearings (or Straw Hat from Branchlines) then you need to add the thickness of the bearings each side. Then add whatever sideplay you're looking for.

 

The 3mm Society standards are at:

https://sites.google.com/site/3mmpublic/technical-notes

E.g. 12mm gauge intermediate standard gives a back to back of 10.3mm

 

However, it is probably best to start with whatever wheels you're going to use (Romfords?) and find out the back to back of those, then work backwards.

 

Remember that model wheels have a bit of slop in them (you can slide them sideways over the track) which helps going round curves, so that even chasses which have little side play in them can go round quite a lot of curves. 

 

Nigel

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I use Tri-ang standards and as Dava says the chassis's are around 9mm wide but the back to back measurement is 10mm for the driving wheels. Having said that their coach and wagon wheels were split so they could move further out to 10.5. As I am replacing the plastic wheels with metal ones I set them at 10. If you look at my videos on YouTube, via links from another thread from here, you will see this is not an issue. The back to back will need to be greater as NCB says to go through modern Peco track, in my case as I use Tri-ang track as well I have modified the Peco points to accept the Tri-ang standards.

 

Garry

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3mm Society standards are https://drive.google.com/file/d/0B0KD5_ptqrd7bFJVeUNXeXJQd2s/view

 

Back to back for 12mm gauge is 10.1mm for Triang wheels, 10.3mm for "Intermediate" wheels, which are like RP25 standard. You need at least 0.2mm side play though if you don't want your chassis binding up though, more for six-coupled chassis and even more for tight curves.

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3mm Society standards are https://drive.google.com/file/d/0B0KD5_ptqrd7bFJVeUNXeXJQd2s/view

 

Back to back for 12mm gauge is 10.1mm for Triang wheels, 10.3mm for "Intermediate" wheels, which are like RP25 standard. You need at least 0.2mm side play though if you don't want your chassis binding up though, more for six-coupled chassis and even more for tight curves.

I know it is not much, 0.1, but the 1957 Tri-ang standards state the Back to Back is 10.00mm.  Wheel thickness 2.75, Flange thickness 0.5mm, Flange depth 0.75mm

 

Garry

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I know it is not much, 0.1, but the 1957 Tri-ang standards state the Back to Back is 10.00mm.  Wheel thickness 2.75, Flange thickness 0.5mm, Flange depth 0.75mm

 

Garry

 

 

Is this just a hope or are Slaters going to do these kits in 4 mm scale again ?

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I know it is not much, 0.1, but the 1957 Tri-ang standards state the Back to Back is 10.00mm.  Wheel thickness 2.75, Flange thickness 0.5mm, Flange depth 0.75mm

 

Garry

 

There might be a bit of history there, but if there is I don't know what

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I know it is not much, 0.1, but the 1957 Tri-ang standards state the Back to Back is 10.00mm.  Wheel thickness 2.75, Flange thickness 0.5mm, Flange depth 0.75mm

 

Garry

 

Is the Triang flange thickness really only 0.5mm?  Don't know, just interested.

 

Nigel

Is this just a hope or are Slaters going to do these kits in 4 mm scale again ?

 

What kits are we talking about?

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Those are just the 1957 Tri-ang quoted figures Nigel. I have not measured any apart from the back to backs but may do tomorrow out of curiosity.

 

Garry

 

Just measured a Jinty, Merchant Navy and BrittanIa. Pretty inconsistent. Metal driving wheels are about 10.0 btb but can be wider. Plastic wheels much greater variation. Flanges anything from 0.5 to 0.65. I assume the track was designed with high tolerances!

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