RMweb Premium corneliuslundie Posted March 27, 2015 RMweb Premium Share Posted March 27, 2015 I want to built a loco kit, my first for many years, with split frames but also using a gearbox. However, it seems impossible to do this as the gearbox will surely short between the frames. I am not worried about insulating the body from the frames, but do any RMWeb members have any suggestions as to how to insulate the metal gearbox from the frames? Jonathan David Link to comment Share on other sites More sharing options...
Quarryscapes Posted March 27, 2015 Share Posted March 27, 2015 In 2mm scale it's done with the gearbox being part of one of the frames and the split being made between in the remaining gap between it and the other frame. Link to comment Share on other sites More sharing options...
garethashenden Posted March 27, 2015 Share Posted March 27, 2015 Yeah, there are two ways to do this. Either way will need to have the split in the split axle between the gearbox and the bearing (which is usually a very small space). 1) Isolate the gearbox. You'll need a three part split axle and two isolating washers to hold everything apart. 2) Have a live gearbox. Forget about isolating it from both sides and concentrate on doing it well on only one side. You'll have a little bit extra space this way. Position the gap in the axle right next to, but outside of, the gearbox bearing. Put a couple of paper washers on the axle to keep things from moving too much. I did my GWR 850 the second way and it works pretty well. I'll try to find a picture that shows what I'm on about. Link to comment Share on other sites More sharing options...
Quarryscapes Posted March 28, 2015 Share Posted March 28, 2015 I'm remembering wrong re 2mm gearboxes, there are pics in the 2mm finesacale section though. Link to comment Share on other sites More sharing options...
billbedford Posted March 28, 2015 Share Posted March 28, 2015 Use a plastic gearbox. Link to comment Share on other sites More sharing options...
kandc_au Posted March 28, 2015 Share Posted March 28, 2015 Can you buy new split axles or do you have to make yourself? Khris Link to comment Share on other sites More sharing options...
RMweb Premium corneliuslundie Posted March 28, 2015 Author RMweb Premium Share Posted March 28, 2015 Thanks. I was going to use EMGS split axles but they have the split to one side of the centre, not close to the frame. It is possible to make one's own but I am not sure I have the tools. A plastics gearbox is an interesting idea but I am not sure how long it would last - and I don't know where to course one. Thoughts? The other course I had thought of, but which would mean some surgery, is to glue a rigid insulated sheet to the transverse piece of gearbox and then split the metal part itself to provide insulation - I know this is not clear. I can see it in my mind but don't know how to describe the parts. Jonathan Link to comment Share on other sites More sharing options...
billbedford Posted March 28, 2015 Share Posted March 28, 2015 A plastics gearbox is an interesting idea but I am not sure how long it would last - and I don't know where to course one. Thoughts? Many of the Bachmann motor carriers/gearboxes are plastic mouldings. If you use one of the High level gearboxes that have extension pieces, the intermediate gears are plastic. If you fix the motor - gearbox assembly in the frames and leave out the extension piece then you should be able to arrange the insulation for the motor an gearbox. It will mean that you will have to make the adjustments for the meshing of the final drive gears, but that won't be too difficult. Link to comment Share on other sites More sharing options...
RMweb Premium corneliuslundie Posted March 28, 2015 Author RMweb Premium Share Posted March 28, 2015 Thanks. That's very useful. I was intending to get a High Level gearbox but had not yet got around to working out which one will fit best. RMWeb triumphs again. Jonathan Link to comment Share on other sites More sharing options...
RMweb Premium Siberian Snooper Posted March 28, 2015 RMweb Premium Share Posted March 28, 2015 Thanks. I was going to use EMGS split axles but they have the split to one side of the centre, not close to the frame. It is possible to make one's own but I am not sure I have the tools. A plastics gearbox is an interesting idea but I am not sure how long it would last - and I don't know where to course one. Thoughts? The other course I had thought of, but which would mean some surgery, is to glue a rigid insulated sheet to the transverse piece of gearbox and then split the metal part itself to provide insulation - I know this is not clear. I can see it in my mind but don't know how to describe the parts. Jonathan Branchlines, supply a 3 piece split axle kit, but getting all 3 bits in line, even using their jig is a right royal pain the **** Link to comment Share on other sites More sharing options...
alfsboy Posted March 28, 2015 Share Posted March 28, 2015 Northwest Shortline (USA)make plastic gearboxes .They can come with a plastic idler gear too and 1/8 axles,choice of motorshaft size etc.I use em to repower brass locos .They work very well . Link to comment Share on other sites More sharing options...
PaulT Posted March 28, 2015 Share Posted March 28, 2015 If you use one of the High level gearboxes that have extension pieces, the intermediate gears are plastic. If you fix the motor - gearbox assembly in the frames and leave out the extension piece then you should be able to arrange the insulation for the motor an gearbox. It will mean that you will have to make the adjustments for the meshing of the final drive gears, but that won't be too difficult. Bill, could you do a sketch of how you see this please? Link to comment Share on other sites More sharing options...
Horsetan Posted March 28, 2015 Share Posted March 28, 2015 Use a plastic gearbox. ....or a plastic-sided one. Link to comment Share on other sites More sharing options...
Mike Riley Posted March 29, 2015 Share Posted March 29, 2015 There is an article in the current Finescale Railway Modelling Review on making split (Romford) axles and pictures of a finished chassis. This shows how the gearbox is insulated. Mike Link to comment Share on other sites More sharing options...
RMweb Premium polybear Posted March 29, 2015 RMweb Premium Share Posted March 29, 2015 Split axles are available from Branchlines, in both 1/8th and 2mm; I'm pretty sure that 2-part and 3-part axles are available, with the latter being for gearbox use to ensure electrical isolation. They also sell a very nice machined perspex jig to aid axle assembly/gluing up. This link is somewhat out of date but hopefully the contact details are still valid: http://branchlines.blogspot.co.uk/ Not sure, but there's a reasonable chance they could be at ExpoEM in May. HTHpolybear Link to comment Share on other sites More sharing options...
RMweb Premium DLT Posted March 29, 2015 RMweb Premium Share Posted March 29, 2015 There is an article in the current Finescale Railway Modelling Review on making split (Romford) axles and pictures of a finished chassis. This shows how the gearbox is insulated. Mike Indeed there is, it shows an excellent way of splitting Romford axles while retaining the self-quartering. However it still doesn't answer the fundamental question, how/where do you split the driven axle? It shows the two sides of the gearbox insulated from each other, but there is still a socking great brass gearwheel on the axle. And in a multistage gearbox like a Highlevel, you have steel cross-shafts bridging the gearbox sides, for the plastic gears to run on. I'm still confused on that one! Cheers, Dave. Link to comment Share on other sites More sharing options...
billbedford Posted March 29, 2015 Share Posted March 29, 2015 The whole gear box can be live to one side, and since some of the HL gearboxes are off set, probably the best way of dealing with them is to split the axle between the gearbox and the opposite frame. Link to comment Share on other sites More sharing options...
garethashenden Posted March 29, 2015 Share Posted March 29, 2015 Thanks. I was going to use EMGS split axles but they have the split to one side of the centre, not close to the frame. It is possible to make one's own but I am not sure I have the tools. A plastics gearbox is an interesting idea but I am not sure how long it would last - and I don't know where to course one. Thoughts? The other course I had thought of, but which would mean some surgery, is to glue a rigid insulated sheet to the transverse piece of gearbox and then split the metal part itself to provide insulation - I know this is not clear. I can see it in my mind but don't know how to describe the parts. Jonathan In EM gauge at least the split does work out as being close to the inside of the frames, at least it did for me... Link to comment Share on other sites More sharing options...
burgundy Posted March 30, 2015 Share Posted March 30, 2015 Jonathan I don't think anyone has mentioned Barry Luck's website which goes into considerable detail about his chassis construction methods using split frames. Aside from his excellent taste in prototypes, he makes it look easy. I have to admit that I am still struggling with my one attempt. Best wishes Eric Link to comment Share on other sites More sharing options...
PGC Posted March 30, 2015 Share Posted March 30, 2015 I don't know how he does it, but John James of Liverpool is a professional builder who builds chassis with split axles - he refuses to build them any other way. He has built a High Level Hudswell Clark Coronation class for me with split axles and to say it's it's tight is an understatement, but he's done it. I will see if I can contact him and find out how he insulates the gearbox. Phil Link to comment Share on other sites More sharing options...
Flymo748 Posted April 7, 2015 Share Posted April 7, 2015 Thanks. That's very useful. I was intending to get a High Level gearbox but had not yet got around to working out which one will fit best. RMWeb triumphs again. Jonathan Hi Jonathan, I don't bother dropping into RMWeb very often, but the fact that this involved kit-building caught my eye. This is a modified High Level gearbox that I built at the Spring Missenden, sitting on the Branchlines tree-part axle that it is intended to fit. I'm not modelling Brunel's Great Endeavour, it's merely that the axle length hasn't been trimmed down from that which it emerged from the jig at. The gearbox has been modified by cutting a slice out of the middle to reduce it in width. It was joined back together by soldering to a piece of scrap nickel silver, which was trimmed to width when all was stout and square: The gearbox will be held centrally by the use of fibre washers. Ask me in a few days if it all works - I was cutting the axles to length yesterday ;-) HTH Flymo Link to comment Share on other sites More sharing options...
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