RMweb Gold JCL Posted December 29, 2019 RMweb Gold Share Posted December 29, 2019 33 minutes ago, hartleymartin said: Not sure how I let that goof get to the laser-cutter oh, it’s very easy, believe me. There are a lot of different parts that have to be defined, and I’d say it would be unusual to get everything right the first go. Here’s how I know. It was not the first iteration of the coach, and I’m designing the brake now, which will be even flakier until I get my first test build done. your model is looking fantastic. Link to post Share on other sites More sharing options...
hartleymartin Posted December 29, 2019 Author Share Posted December 29, 2019 Had to make a few adjustments to the roof underframe. It was about 1mm too long and needed a few passes of the file down the sides to fit inside the built up body. Had a real hard time figuring out how to attach the arc roof to the frame, until I remembered that clothes pegs are basically lots of tiny spring clamps. 3 Link to post Share on other sites More sharing options...
hartleymartin Posted December 30, 2019 Author Share Posted December 30, 2019 Can anyone offer suggestions as to suitable card materials for the roof? Whilst it was cut in 0.8mm laser-ply, I have found that the roof is too stiff, and the sides will leave irregular gaps. I'm wondering if it may be better to design it so that the roof and body are one piece that separates from the chassis for the purposes of interior painting, detailing, etc. Link to post Share on other sites More sharing options...
MGR Hooper! Posted December 30, 2019 Share Posted December 30, 2019 2 hours ago, hartleymartin said: Can anyone offer suggestions as to suitable card materials for the roof? Whilst it was cut in 0.8mm laser-ply, I have found that the roof is too stiff, and the sides will leave irregular gaps. I'm wondering if it may be better to design it so that the roof and body are one piece that separates from the chassis for the purposes of interior painting, detailing, etc. Normal plasticard? Link to post Share on other sites More sharing options...
hartleymartin Posted December 30, 2019 Author Share Posted December 30, 2019 The only trouble with plasticard is that I've had warpage problems over the years and as this is an unsupported roof over an end verandah, I want something that will stay put for the most part. At one stage, I was going to just use strips of scale timber glued together and sanded to shape in the manner of carvel planking, but not something I'd recommend. 1 Link to post Share on other sites More sharing options...
MGR Hooper! Posted December 30, 2019 Share Posted December 30, 2019 Painting the underside with super-glue will prevent warping. 1 Link to post Share on other sites More sharing options...
MarcD Posted December 30, 2019 Share Posted December 30, 2019 It would work on the same principle as doping an aircraft wing. Marc Link to post Share on other sites More sharing options...
hartleymartin Posted January 2, 2020 Author Share Posted January 2, 2020 A re-design of the kit is that the body and roof will glue up as one piece and the floor/chassis will be a separate piece. I have to re-design a few things since the arrangement of the tabs and slots assumes building the body on top of the floor, but this will ensure that the roof forms perfectly to the body. Link to post Share on other sites More sharing options...
monkeysarefun Posted February 6, 2020 Share Posted February 6, 2020 (edited) Found these in a facebook group about the Camden to Campbelltown tramline... KA 778 arriving at Parramatta Park 9-3-1972 KA 778 at Cootamundra, January 1972. It had been a First Aid station. Edited February 6, 2020 by monkeysarefun 1 Link to post Share on other sites More sharing options...
Marbelup Posted February 14, 2020 Share Posted February 14, 2020 An old venetian blind slat could work for the roof, especially if you can get one from an older house with the wider slats. I have a stock of them which I have used in the past for 4 wheel vans and a small railmotor. 1 Link to post Share on other sites More sharing options...
hartleymartin Posted March 6, 2022 Author Share Posted March 6, 2022 A little over 2 years later. Yeah, there was some global emergency which distracted us all for a while. I have a test-build, with annotations written on to correct some dimensional errors. Unfortunately, about 6 months ago my old computer up and died, and I am not sure if the original CAD files managed to make the transition to the new machine. I only have the svg files exported for the laser-cutter, but not the odg files which has all the original features and points. But I know that those drawings are 90%+ correct and complete so I can leave them alone. I will have to redraw the underframe components. I am looking to obtain near-enough components from existing manufacturers' catalogues to complete the model, but the one thing which remains is the bogies. I learned to do the 2D CAD for laser-cutting and that I adequately understand. I don't really want to learn 3D CAD just for the bogies. I have decided to change the way the model is assembled. I had originally wanted to keep the roof a separate component, but I get bad gaps in the join which I cannot correct. I think now that it should be that the body and roof are assembled together and the floor/chassis is the separate component. I am less concerned with getting everything 100% correct, as no two photographs or drawings show exactly the same details on KA Tramcars. It seems that with just four carriages ever built, all of them were eventually unique and had different appearances at different times and places. 3 1 Link to post Share on other sites More sharing options...
hartleymartin Posted March 6, 2022 Author Share Posted March 6, 2022 Also, just saying that if someone is able to do the patternwork for the bogies for me, I am sure we can come to some arrangement where I will send you all the other components for you to build your own KA Tramcar or something similar. Link to post Share on other sites More sharing options...
hartleymartin Posted March 8, 2022 Author Share Posted March 8, 2022 (edited) So we are now at revision 20 of the laser-cutting artwork. Mostly minor dimensional adjustments to some of the underlaying roof components, Correction to the bogie pivot points (10mm too far apart on Rev 19) And additional slots and tabs to cater for new assembly method where roof and body are a single component and the floor/chassis/underframe are a single component. I no longer have the original drawing files, but I do have the *.svg export files where individual elements can no longer be edited, but I can always place a white box over sections and draw new lines over them. Edited March 8, 2022 by hartleymartin 3 Link to post Share on other sites More sharing options...
hartleymartin Posted March 8, 2022 Author Share Posted March 8, 2022 And now on Revision 4 of the underframe components. I plan to have this cut in 2.5mm Basswood, but 2.5mm Plywood will also work. The triangles are fillet pieces which will be used to strengthen the connection with the bufferbeams. I plan to use Dapol screw-link couplings pre-assembled. I tried several times to assemble the slaters working screw link couplings, and probably could have bought several wagon kits with the money. I botched every single attempt, so I gave up on those. I have also identified several components from an American manufacturer which appear to be suitable, or at least close-enough to save me the bother of scratch-building them: 3 Link to post Share on other sites More sharing options...
hartleymartin Posted March 8, 2022 Author Share Posted March 8, 2022 On 14/02/2020 at 21:42, Marbelup said: An old venetian blind slat could work for the roof, especially if you can get one from an older house with the wider slats. I have a stock of them which I have used in the past for 4 wheel vans and a small railmotor. I did look into that, but found that I could get what I needed from 0.8mm plywood. I have drawn that component up, but not shown it since it is basically a rectangle with rounded corners, a few holes for the oil-lamp pots and scribed planking lines which also help make it more bendy on the ribs which form the arc. Link to post Share on other sites More sharing options...
monkeysarefun Posted March 8, 2022 Share Posted March 8, 2022 On 06/03/2022 at 20:31, hartleymartin said: Also, just saying that if someone is able to do the patternwork for the bogies for me, I am sure we can come to some arrangement where I will send you all the other components for you to build your own KA Tramcar or something similar. Hey mate, would you be looking at 3D printing them? Link to post Share on other sites More sharing options...
hartleymartin Posted March 10, 2022 Author Share Posted March 10, 2022 On 09/03/2022 at 10:45, monkeysarefun said: Hey mate, would you be looking at 3D printing them? I've contacted Tim at CWRailways to do the 3D CAD artwork. I considered 3D-printed bogies, but I am concerned they would not be durable enough in O gauge. I am looking at 3D-printed masters then having a batch cast in either brass or pewter. Link to post Share on other sites More sharing options...
MarcD Posted March 10, 2022 Share Posted March 10, 2022 I would depend on the plastic used in the print and the technique used to print them. But some plastics would be able to cope. I'm experimenting with printing wheel centres using an ABS equivalent and it looking ok. Marc 1 Link to post Share on other sites More sharing options...
hartleymartin Posted April 1, 2022 Author Share Posted April 1, 2022 On 10/03/2022 at 21:18, MarcD said: I would depend on the plastic used in the print and the technique used to print them. But some plastics would be able to cope. I'm experimenting with printing wheel centres using an ABS equivalent and it looking ok. Marc Marc - I may have to follow you up on that. I would like the prototype 8-spoke locomotive wheels for the Australian Manning Wardle locomotives which are not produced by Slaters or any other wheel manufacturer I am aware of. Link to post Share on other sites More sharing options...
hartleymartin Posted April 1, 2022 Author Share Posted April 1, 2022 (edited) I discovered that I am eligible to use AutoCAD under education access so I am using it to fix up the old drawings. I no longer have access to the original drawing files, but I do have the PDFs exported from them, which I have been able to import and convert to a proper CAD drawing. I get much better precision than I ever could on the other program. This revelation came about because I had to complete a number of hours of CAD exercises as part of my furniture-maker's trade certificate. I've learned the basics of 2D CAD in a program that makes sense to me. Edited April 1, 2022 by hartleymartin 2 Link to post Share on other sites More sharing options...
DGO Posted April 1, 2022 Share Posted April 1, 2022 1 hour ago, hartleymartin said: I discovered that I am eligible to use AutoCAD under education access so I am using it to fix up the old drawings. I no longer have access to the original drawing files, but I do have the PDFs exported from them, which I have been able to import and convert to a proper CAD drawing. I get much better precision than I ever could on the other program. This revelation came about because I had to complete a number of hours of CAD exercises as part of my furniture-maker's trade certificate. I've learned the basics of 2D CAD in a program that makes sense to me. If the pdfs are direct from a drawing program you can import them straight into Autocad with the pdf import function, some train manufacturers provide line drawings in their pdf brochures that can be imported this way, if you happen to know a few key dimensions of the real thing this becomes really useful for modern stuff Link to post Share on other sites More sharing options...
hartleymartin Posted April 1, 2022 Author Share Posted April 1, 2022 Preview of what I think is now Revision 21 of the drawings. On the right-hand side are the parts where I have completed the revision work, and on the left are the old source images which I have to revise/redraw. Now that I am able to use AutoCAD I have been able to accurately plot the roof arc and make all the ribs and parts for the roof a consistent radius - something which was lacking in the old software. 2 1 Link to post Share on other sites More sharing options...
hartleymartin Posted April 2, 2022 Author Share Posted April 2, 2022 Today I showed the old test-build at the Aus7 Forum (twice-yearly O gauge convention in Sydney) and got quite a bit of interest. I came home and started working on Revision 22 of the drawings. This has been immeasurably easier in AutoCAD than it had been in the previous drawing program. It seems that a lot of drawing programs fall down when it comes to drawing curves and tangents. The significant work done in these drawings is not immediately obvious. It is a re-design of the parts so that the body and roof are assembled as a series of sub-assemblies which are glued together and the floor level and chassis will separate. The plan is to use four screws to hold the chassis and body together. This way it is possible to access the interior for detailing - maybe some basic seating for passengers. I do not plan to make a lot of interior detail, but just enough suggestions of an interior. 4 Link to post Share on other sites More sharing options...
hartleymartin Posted December 28, 2022 Author Share Posted December 28, 2022 I will be picking up this project again in the future. Currently considering the possibility of getting my own small laser-cutter. 2 Link to post Share on other sites More sharing options...
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