Baldwin30762 Posted March 31, 2018 Share Posted March 31, 2018 (edited) 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 March 31, 2018 by Baldwin30762 Link to post Share on other sites More sharing options...
RMweb Premium Dava Posted March 31, 2018 RMweb Premium Share Posted March 31, 2018 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. 1 Link to post Share on other sites More sharing options...
RMweb Premium NCB Posted March 31, 2018 RMweb Premium Share Posted March 31, 2018 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 Link to post Share on other sites More sharing options...
Baldwin30762 Posted April 1, 2018 Author Share Posted April 1, 2018 Thanks Guys that is just what I was after. Colin Link to post Share on other sites More sharing options...
Golden Fleece 30 Posted April 2, 2018 Share Posted April 2, 2018 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 Link to post Share on other sites More sharing options...
whart57 Posted April 2, 2018 Share Posted April 2, 2018 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. Link to post Share on other sites More sharing options...
Golden Fleece 30 Posted April 10, 2018 Share Posted April 10, 2018 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 Link to post Share on other sites More sharing options...
hayfield Posted April 10, 2018 Share Posted April 10, 2018 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 ? Link to post Share on other sites More sharing options...
whart57 Posted April 10, 2018 Share Posted April 10, 2018 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 Link to post Share on other sites More sharing options...
RMweb Premium NCB Posted April 10, 2018 RMweb Premium Share Posted April 10, 2018 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? Link to post Share on other sites More sharing options...
Golden Fleece 30 Posted April 10, 2018 Share Posted April 10, 2018 (edited) 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 Edited April 10, 2018 by Golden Fleece 30 Link to post Share on other sites More sharing options...
simonfish45 Posted April 11, 2018 Share Posted April 11, 2018 1/16" frames soldered either side of a 1/4" brass bar, leaving a gap for the driving cog, gives you +/- 0.5mm wriggle room on a tri-ang back-to-back wheel set. Simon Link to post Share on other sites More sharing options...
whart57 Posted April 11, 2018 Share Posted April 11, 2018 From what I recall, the earth pin of a broken 13 amp plug was just the right size. Link to post Share on other sites More sharing options...
RMweb Premium NCB Posted April 11, 2018 RMweb Premium Share Posted April 11, 2018 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! Link to post Share on other sites More sharing options...
hayfield Posted April 12, 2018 Share Posted April 12, 2018 Is the Triang flange thickness really only 0.5mm? Don't know, just interested. Nigel What kits are we talking about? I had hoped the 4 mm range of coach kits would be back in circulation Link to post Share on other sites More sharing options...
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