garygfletcher Posted May 7, 2015 Author Share Posted May 7, 2015 You don't need bushes if you use the 0.5 mm P/B strips as chassis frames. That could expedite things then if I epoxy then to the acrylic? Link to post Share on other sites More sharing options...
garygfletcher Posted May 7, 2015 Author Share Posted May 7, 2015 It looks really great, but ... do you intend this to be way you do it for the real loco. It's just, at least on the loco, the acrylic is filling valuable space both in the loco and that should contain something heavier, to add weight for adhesion. And for a Spinner, you are going to need that adhesion. Chris Hi Chris To be honest I don't know, at the very least it makes a nice template and took minutes to fabricate. I'll get a better feel when I look at the gearing. Thanks Gary Link to post Share on other sites More sharing options...
garygfletcher Posted May 7, 2015 Author Share Posted May 7, 2015 Well, I would guess that the number of broken/dulled milling bits at least cancel outs the savings.Would love to hear more on your experiences with CNC milling, Gary. Feeds & speeds and cutter types are something I am struggeling quite a bit with... Surprisingly not, using a high end 0.6mm carbide 2 flute bit (not Chinese) stepping at 0.1mm asserts little pressure and I have a very high end balanced spindle. i think this will last some time. Also managed to mill 6mm brass smoke box with a 1mm cheap chinese bit using the same increments. Speed wise same as aluminium for me and I am undecided about cutting fluid, brass chips quite nicely and probably doesn't need it. 1.5mm brass I am struggling strangely to find a sweet spot. Really I need to find a supplier for nickel silver, for brass its just been so easy to use ebay and it arrives next day and very cheap too! Link to post Share on other sites More sharing options...
Chris Higgs Posted May 7, 2015 Share Posted May 7, 2015 That could expedite things then if I epoxy then to the acrylic? True, I presume you can work out some way that the frames can be auto-aligned with the block. Otherwise I personally would still use the bushes as a nice easy way to do that. Also is it more of a bother milling the 0.5mm frames than it is if they are only 0.25mm thick? Chris Link to post Share on other sites More sharing options...
garygfletcher Posted May 7, 2015 Author Share Posted May 7, 2015 Sorry I was more so thinking epoxying the bushes to the acrylic, if I used the phosphor bronze strips I'd drill and tap then into the acrylic. I've milled upto 6mm brass, these frames would probably take 12 mins to mill 4 ie 2 sets. I couldn't do that by hand that fast or as accurate copies. Link to post Share on other sites More sharing options...
Chris Higgs Posted May 7, 2015 Share Posted May 7, 2015 Sorry I was more so thinking epoxying the bushes to the acrylic, if I used the phosphor bronze strips I'd drill and tap then into the acrylic. That would work, but then you need a wire to each one for the pickup. The strip acts as its own pickup. Chris Link to post Share on other sites More sharing options...
RichardW1 Posted May 7, 2015 Share Posted May 7, 2015 Tapping into the acrylic... That can be a challenge in small sections as it is very brittle and the tap can easily crack the material. Not impossible to do, but care is needed. I'm with Chris here. I'm all for using modern technology, so by all means use the acrylic material to prove the development. However, if you want reliable locos Mr Newton's invention is paramount to ensure reliable electrical contact between wheel and rail , and axle to chassis. Electrical reliability and traction rely heavily ('suse the pun) on mass. Too many commercial locos are seriously wanting for additional weight. Richard. Link to post Share on other sites More sharing options...
garygfletcher Posted May 12, 2015 Author Share Posted May 12, 2015 I have managed to thoroughly confuse myself... I *think I may have sized the wheels incorrectly?? 7mm for the bogie (from 3' 6 ½") 8.5mm for the rear loco wheel (from 4'6" ). 8mm for the tender wheels (from 4'3" ). 15mm custom made wheel for the spinner (from 7' 6") I *think my plan drawings are based on the wheel diameter, in this case I think I could 1) Use the association 14mm tyre for the spinner wheel which has an outer diameter of 15mm 2) go down half a mm on the other wheels? e.g. 6.5mm for the bogie, 8mm for the rear loco wheel, 7.5mm for the Johnson Tender? Does this make any sense? Link to post Share on other sites More sharing options...
RMweb Gold queensquare Posted May 13, 2015 RMweb Gold Share Posted May 13, 2015 I have managed to thoroughly confuse myself... I *think I may have sized the wheels incorrectly?? 7mm for the[/size] bogie (from [/size]3' 6 [/size]½[/size]") [/size] 8.5mm for the rear loco wheel (from 4'6" ). 8mm for the tender wheels (from 4'3" ). 15mm custom made wheel for the spinner (from 7' 6") I *think my plan drawings are based on the wheel diameter, in this case I think I could 1) Use the association 14mm tyre for the spinner wheel which has an outer diameter of 15mm 2) go down half a mm on the other wheels? e.g. 6.5mm for the bogie, 8mm for the rear loco wheel, 7.5mm for the Johnson Tender? Does this make any sense? I think giving yourself a little bit of wriggle room regarding wheel sizes is eminently sensible, the over scale flanges of Association standards will more than make up any visual impact of a slightly undersized wheel. I think I would probably go with 6.5mm, 14mm and 8mm for the loco and stick to 8mm for the tender. Out of interest, what do you propose doing for the driver. Jerry Link to post Share on other sites More sharing options...
garygfletcher Posted May 27, 2015 Author Share Posted May 27, 2015 Quick question, what is the best method to bend the cab roof and wheel arches? Link to post Share on other sites More sharing options...
Caley Jim Posted May 27, 2015 Share Posted May 27, 2015 Quick question, what is the best method to bend the cab roof and wheel arches? Roll between a suitable diameter piece of rod and a mouse mat. It may take several goes with increasing pressure to achieve the required radius - start with light pressure. For the cab roof (and any roof) I find it a good idea to roll to a slightly tighter radius than required, then solder in the centre of each end first, making sure the roof is tight down on the centre of the end/cab front. That way the edges will be hard down on the sides. Much easier than trying to get the edges tight on the sides if the roof is slightly too flat. Jim Link to post Share on other sites More sharing options...
RMweb Premium Nig H Posted May 28, 2015 RMweb Premium Share Posted May 28, 2015 Quick question, what is the best method to bend the cab roof and wheel arches? Have you tried this technique for the splasher tops? http://www.rmweb.co.uk/community/index.php?/topic/95398-rolling-your-own/?p=1788437 Nig H Link to post Share on other sites More sharing options...
Horsetan Posted June 19, 2015 Share Posted June 19, 2015 ....There's only one way to learn how to build locos in 2FS and that is get stuck in and try it! If it doesn't work out the first time, learn where you went wrong and have another go! (Ooops, that's 2 bits of philosophy!) Link to post Share on other sites More sharing options...
garygfletcher Posted July 27, 2015 Author Share Posted July 27, 2015 So for a while now I have had a box of parts which I recently re-cut from nickel and I met Mark Fielder recently who gave me a whole host of tips and tricks especially on the soldering side of things. After being out of the country for nearly a month, tonight I decided to have a bash and see if the parts actually fit together and have a go at the soldering again well they say practice makes perfect and I am definitely going to need some more. Also need to work on bending techniques but it has the right shape and the parts look good. That said I am quite happy with the way it looks, I may fiddle with it a little more before I scrap it and start on the freshly cut parts I have... Link to post Share on other sites More sharing options...
garygfletcher Posted August 12, 2015 Author Share Posted August 12, 2015 If you have been following this post you'd know that I built a 3d model to extract the CNC paths from to cut my metal pieces from. Well I was curious how far I could push the 3d boundary and decided to make a specific model to incorporate this pushing of the bar. This resulted in using extremely tight tolerances and the agency writing back to me telling me they didn't think it was possible, I asked them to try and it was 95% successful, with some further refinements required. I also sent off a series of wheel sets indifferent sizes, again because the tolerances were so tight I wondered what ones would come back in pieces, I am glad to say the correct scale wheels were fabricated, but without some bevels and so I will try to incorporate them into the next version. I am very pleased with the results of both parts. The loco itself in my opinion is ready to paint with no further working. The wheels need taking down a fraction. However I do wonder if this is a way forward for mass production (well multiple production) or whether it is just too light in comparison to a metal frame. I think if I went this way I would add a lot more detail now I can see the limitations in person. Appreciate thoughts as always. Thanks Gary Link to post Share on other sites More sharing options...
garygfletcher Posted August 12, 2015 Author Share Posted August 12, 2015 better wheel picks Link to post Share on other sites More sharing options...
garygfletcher Posted August 12, 2015 Author Share Posted August 12, 2015 Here are the wheels as they appear in the association 14mm rims, which actually seem to have the correct 15mm outside diameter for the spinner. Link to post Share on other sites More sharing options...
John lewsey Posted August 14, 2015 Share Posted August 14, 2015 Erm wow Link to post Share on other sites More sharing options...
garygfletcher Posted October 8, 2015 Author Share Posted October 8, 2015 So little bit of an update here,I've been incredibly lucky and had the opportunity to spend a day with Mark Fielder and Tim Watson running through some basic techniques and now I feel a whole lot more confident in the basics thanks to their hands on insights and tutorage that I've now heavily invested in some very expensive tools and converted one of my office desks wholly to 2mm Boy this is an expensive hobby! But what really pushed home to me by both Mark and Tim was that quality tools in this hobby can save huge amounts of time and if looked after can last a lifetime and I certainly feel passionate and committed enough to have made that investment. Very grateful for their time. unfortunately I have been quite busy lately and just not been home to really make a start on anything and really get everything where I want it and bed in, hopefully that will change a little over this weekend. That said while I have been away I could work on some digital files and I have done just that. Again pushing the boundaries to the extreme and getting some wonderful advice from Jerry Clifford who is keen on the 3d printing but holds similar reservations to Tim about its practicality. Jerry is helping me do a little experimenting and in fact I have sent him some wheels and 2 locos to play with. I am hoping Jerry and I can look at casting some of the smaller stuff from a special 3d resin I have purchased. However there is a little twist, as I mentioned whilst I have been away I have been working on some digital 3d modelling - but in a different format not resin based but wax based 3d printing which is then cast by the agency. After speaking to both Jerry and Tim it is the complex shapes that would benefit from from 3d printing so I decided to have a go at the Spinner Boiler there are a huge number of complexities when designing something so small with a minimum resolution of 0.8mm here is an example. On the bottom of the smoke box there are two protruding cubes this is because the curve narrows down to ensure this can be printed in wax the thickness needs to be 0.8 so at these narrow edges extra material has been added to be filed down. On this image above you can also see the inside wax pattern which has not been polished and how crude the technique is, yet the end result is quite spectacular in my opinion - although not cheap, these boilers cost around £45 each, but they offer the perfect hybrid solution to developing complex shapes repetitively and the dream is to have many of this spinners running up and down the line. Here are some more images showing some sprew work for the chimneys, buffers (resolution is 0.3mm here and so not suitable for the 0.8mm brass) and johnson tender tops as proof of concept. And some pictures of the boilers sat on the demo parts I put together with Tim and Mark... Link to post Share on other sites More sharing options...
richbrummitt Posted October 12, 2015 Share Posted October 12, 2015 Hello Gary, My interest is piqued regarding the brass casting. I've long thought that belpaire fireboxes (and maybe also to a lesser extent the tapered boilers of WR engines) are a brilliant candidate for this kind of technique but the cost has put me off experimenting. Have you made any measurements regarding how much material is lost to the polishing/finishing and/or shrinkage when casting that you then consider when preparing the 3D data? Finally (for now at least) who have you used for prints/waxes/casting? Thanks, Richard. Link to post Share on other sites More sharing options...
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