Doncaster Posted November 28, 2020 Share Posted November 28, 2020 (edited) Good morning folks, This is my first constructional post in this section so please be gentle. Its about tandem points and this is my first go with separate chairs. Oh yes it's 18.2mm EM Gauge with Exactoscale chairs. I've built some standard turnouts already. I've got a Templot print for my new layout and it includes a couple of tandems. I got the timbers cut and stuck down, I even cut and shaped my first bit of rail and then I realised I had a problem. There's no gap between the heel of the first point blade and the toe of the second and thats blown my planned chair usage out of the water. Ive labelled up this photocopy with chair positions. I was expecting to use my previous practice of slide chairs in positions 1-6, then special chairs in 6-9, then small chairs in 10-12. However the arrival of the second point blade means I can't do that. I've thought about extending the base on slide chairs but thought I'd ask the question because I'm sure this is just down to my inexperience. Any help or suggestions gratefully received. Thanks. Vernon Edited November 28, 2020 by Doncaster Speeling Link to post Share on other sites More sharing options...
RMweb Gold martin_wynne Posted November 28, 2020 RMweb Gold Share Posted November 28, 2020 Hi Vernon, Did you create that tandem yourself or use the automatic function in Templot? The reason I ask is because you have the two switches too close together. There isn't room to open the second switch blade on the right-hand side (timber28). You have only about 3" between the rails at the blade tips. You need usually at least 8" between the rails at the switch tips (say 3 rail widths). The prototype switch opening is 4.1/4" and in EM you need more (1.75mm = thickness of 20p coin as a setting gauge). Add on the width of the blade foot, plus the outer end of the slide chair and its fixing, and you can see that you need at least 2.75mm for the blade to open (plus some space for the stretcher bar fixing). I suggest you re-create the tandem with a greater distance between the two switches. You will then be able to arrange the chairing. p.s. if you re-arrange the order of the templates in the storage box, with the switch templates at the bottom of the list, the rail edges at the switch will print correctly. cheers, Martin. Link to post Share on other sites More sharing options...
Doncaster Posted November 28, 2020 Author Share Posted November 28, 2020 31 minutes ago, martin_wynne said: Hi Vernon, Did you create that tandem yourself or use the automatic function in Templot? The reason I ask is because you have the two switches too close together. There isn't room to open the second switch blade on the right-hand side (timber28). You have only about 3" between the rails at the blade tips. You need usually at least 8" between the rails at the switch tips (say 3 rail widths). The prototype switch opening is 4.1/4" and in EM you need more (1.75mm = thickness of 20p coin as a setting gauge). Add on the width of the blade foot, plus the outer end of the slide chair and its fixing, and you can see that you need at least 2.75mm for the blade to open (plus some space for the stretcher bar fixing). I suggest you re-create the tandem with a greater distance between the two switches. You will then be able to arrange the chairing. p.s. if you re-arrange the order of the templates in the storage box, with the switch templates at the bottom of the list, the rail edges at the switch will print correctly. cheers, Martin. Hi Martin, Thank you for your advice. I must admit that I was concerned that they were too close together. The Templot was produced for me by a friend so I will have to ask for an amendment. Vernon 1 Link to post Share on other sites More sharing options...
hayfield Posted December 30, 2020 Share Posted December 30, 2020 Vernon You have to think on your feet with the chair positions on 3 ways and tandems as the Exactoscale special chairs are designed for specific purposes. However right from the start I asked Len Newman (the designer) what to do about a 1-6 slip, his advice was to use the parts for a 1-7. I approach the fitting out of a 3 way or tandem in a similar manner. Firstly I save my used sprues, they have numerous unused chair parts. and are all bagged up so I can find an alternative part when required I start building the turnout by fitting the common crossings much the same way as I would a normal single turnout as the outer two common crossings are relatively standard, it is the lead common crossing where things start to become complicated. You need to consider how each rail interacts with those next to it. I do find the spare parts from both the slip and obtuse sprues very useful and never forget switch and common crossing chairs. Its a bit like a jigsaw in finding a part chair which both does what is required and fits I tend to chair up the switch rails and do plenty of dry runs. I must admit its quite fun Link to post Share on other sites More sharing options...
hayfield Posted December 30, 2020 Share Posted December 30, 2020 I don't know if these photos during a build help A closer view of the common crossings, as you can see issues arising around 1st common crossing The missing timbers act as tiebars, they are PCB strips with metal slide chairs The only photo I have of the completed tandem, the best bit of cropping my software does These are the 2 sprues in the slip set. I think these packs are £2, as you can see a range of chairs including slide, and slab and bracket and various block chairs These block chairs are very useful a chair with a half chair attached Or rother one part of a block chair which holds 2 rails. Just find the nearest match 1 Link to post Share on other sites More sharing options...
Doncaster Posted December 31, 2020 Author Share Posted December 31, 2020 Hi Hayfield, Thank you for your helpful comments. I have been using the Exactoscale chairs as I progress and I agree that you shouldn't throw the spares away. Working in EM I'm chopping the special chairs up anyway. I've been working with my revised Templot and I've got one tandem completed and the adjacent turnout with trap virtually there. One more tandem to go. Until recently I've always had running rights on other's layouts, which combined with lots of house moves to deter me from building a layout. A friend's sad death and the covid situation have pointed me towards building a layout. I hadn't built any turnouts since the 1980s. I much prefer the ply sleeper and cosmetic chair approach over copper clad. Vernon 5 Link to post Share on other sites More sharing options...
hayfield Posted December 31, 2020 Share Posted December 31, 2020 Vernon Looks an excellent bit of track building 1 Link to post Share on other sites More sharing options...
Doncaster Posted December 31, 2020 Author Share Posted December 31, 2020 1 hour ago, hayfield said: Vernon Looks an excellent bit of track building Thank you for that. I'm pleased with it so far. Vernon Link to post Share on other sites More sharing options...
Doncaster Posted January 8, 2021 Author Share Posted January 8, 2021 Hi folks, Well I've got there! My test article runs everywhere fine and I can run a loco through, although it's a bit of a faff with lots of Croc clips at the moment. I'll add the tie bars when the track is in situ. Thank you for your help and advice. Cheers, Vernon 1 Link to post Share on other sites More sharing options...
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