RMweb Premium CF MRC Posted November 12, 2015 RMweb Premium Share Posted November 12, 2015 Open out the bearing holes, so the bearings have some adjustment, then some form of alignment jig through the rods to position the bearings for soldering. I have used some amazingly complicated sorts of jigs (commercially available) when attempting to resurrect recalcitrant P4/EM chassis at the Missendon Abbey modeller's weekend. I don't think jigs would achieve the required accuracy for a 2 mm chassis: the commercial gadgets are usually no better than a British standard eyeball and common sense. Tim Link to post Share on other sites More sharing options...
Chris Higgs Posted November 13, 2015 Share Posted November 13, 2015 (edited) I fully agree with this. Nothing looks quite like steel as steel! Likewise, nothing looks quite like coal except coal! :-) I'm wondering how I could make steel rods to match etched n/s chassis? Perhaps etching the rods in steel from artwork off the same CAD drawing, but that would prohibitively expensive unless you were etching a lot of rods. Perhaps the best option would be not to etch the bearing holes, and then use the scratchbuilt rods as jigs to drill them as i have always done in the past. BTW, it must be nearly a decade since I built a loco (though I have re-built a couple of chassis), so maybe I'm due one too!! Jim As far as I am aware, you cannot etch in mild steel, which is what you really want. Stainless steel yes (and we have some rods in the shop) but for me that just ends up too shiny. How about using the rods provided in the etch to drill the holes as the starting point of the steel rods. You could also make some custom 'bearings' to fit into the etched chassis sideframes with a 0.5mm hole in them to then drill the rods. I have also wondered about milling 2mm rods. Perhaps too small? 7mm scale milled coupling rods look just so much better than etched ones. Chris Edited November 13, 2015 by Chris Higgs Link to post Share on other sites More sharing options...
RMweb Premium CF MRC Posted November 13, 2015 RMweb Premium Share Posted November 13, 2015 I have also wondered about milling 2mm rods. Perhaps too small? 7mm scale milled coupling rods look just so much better than etched ones. Chris I tried millng the slots in some steel using my Cowells milling machine. This is an excellent machine but not fast enough for a small bur to mill and be driven by hand consistently. I may try it again with a different type of bur for the con rods. I am sure that there are small CNC mills out there that would do the job, but the end result would probably need a very careful clean up. Tim Link to post Share on other sites More sharing options...
garethashenden Posted November 13, 2015 Share Posted November 13, 2015 Thank you for all that Tim, it's very informative. What width is your slotting file? They seem to come in a range, 0.010" and up. Link to post Share on other sites More sharing options...
RMweb Gold Argos Posted November 13, 2015 RMweb Gold Share Posted November 13, 2015 Chris, I milled the rods for my 171 tank build. They were the second item I ever milled so there is a way to go to perfection but I don't think they are too shabby. It can be done. The ones on the bottom were my first attempt at filing from brass bar. Angus Link to post Share on other sites More sharing options...
Caley Jim Posted November 13, 2015 Share Posted November 13, 2015 (edited) How about using the rods provided in the etch to drill the holes as the starting point of the steel rods. You could also make some custom 'bearings' to fit into the etched chassis sideframes with a 0.5mm hole in them to then drill the rods. Chris A thought I've had since raising this is to etch a jig with holes which could be used to drill the rods. This would have to be done after filing the rods to shape as that process can result in slight stretching of them. This is not an issue if you use the finished rods as a jig to drill the frames, but could be a problem with what I'm thinking about if you used the etched jig before forming the rods. Jim Edited November 13, 2015 by Caley Jim Link to post Share on other sites More sharing options...
RMweb Gold Donw Posted November 13, 2015 RMweb Gold Share Posted November 13, 2015 In 7mm I have a chassis assembly jig. I suppose the wider frame spacing makes errors of parallel more of a problem. The usual procedure is to use the rods to set the jig up then to fix the bearing/hornboxes in the frames on the jig so the axles will be spaced to the jig. The parts used to set the bearings have a short length of smaller diameter on the ends to fit the rods. Perhaps in 2mm the clearance required to make the parts slide would be enough to spoil the accuracy. The main reason to use one is to make sure the frames bearings etc end up correctly aligned. In 2mm those designing the etches seem to have found alternative approaches which work well enough. Don Link to post Share on other sites More sharing options...
MinerChris Posted November 14, 2015 Share Posted November 14, 2015 (edited) The Salt lake city branch of the Carlson wagon workshop continues at a pace, albeit glacial, with a Harris all steel open and a couple of Bob Jones' 21T hoppers... Painting of all wagons in the works is still ongoing. Thanks to a free shipping voucher from Shapeways, and the new FXD material I decided to push the limits of what can be done... Yes that's right, 3D printed ground signals for St Ruth (12" WR style disks), its not too bad on first glance and has surprisingly mostly survived the shipping across the country. for comparison, the original design. I suspect making these work, and attaching a lamp is going to be challenging to say the least. Best Regards, Chris. Edited November 14, 2015 by MinerChris 14 Link to post Share on other sites More sharing options...
RMweb Premium CF MRC Posted November 15, 2015 RMweb Premium Share Posted November 15, 2015 Started work on the driven axle for the P2. The wheels have 1/16" axles and the final gear I am using has a 2mm bore. This was bushed with a piece of acetal, centre bored to 1mm and 0.10" over length to guarantee that the gear was insulated from the chassis sides. The axles were turned down in a step collet to 1.07mm, retaining the 1/16th shoulder for the bearing/chassis. Important to put a slight 'lead' (0.95mm diameter over 1mm) on the axle end to get it to enter the muff comfortably. The wheels were gently offered up to the gear, as can be seen, but this set up will not be pushed home and used until the gearbox is assembled. For checking out the chassis a dummy muff has been made to identical width, which brings the back to back up to the correct 0.335". Should get the chassis together pretty soon - I'll probably need to narrow the front and back a bit to get it round 600 mm curves. I may make some assembling muffs with grub screws so that I can check out the valve gear easily: this is what Denys used to do. It's 40 years since I made an engine with Walschaerts valve gear! Tim 5 Link to post Share on other sites More sharing options...
RMweb Gold queensquare Posted November 15, 2015 RMweb Gold Share Posted November 15, 2015 Looking forward to seeing the P2. Having handled the body (so to speak!), it should be an impressive beast. I like that step collett, that looks a really useful bit of kit. Jerry Link to post Share on other sites More sharing options...
RMweb Premium CF MRC Posted November 16, 2015 RMweb Premium Share Posted November 16, 2015 (edited) I've been working on the P2 chassis today. The cylinder blocks (literally, at this stage) were super glued to the chassis sides and pilot holes drilled through from the frames (already drilled) for the eventual screw fixing. This was easier done with the frames still separated. The blocks eventually will be drilled for the pistons, rear stuffing boxes, slide bars and valve spindle guides along with being shaped appropriately. The odd shape with a screw hole in the bogie cut out is for my frame assembly jig, which I will show in the next post. The second photo shows a mod to the chassis sides. On real engines the wheel rims are very very close to the frames. The wheels do not have a rear boss which puts them nice and close to the frames, but also gives a strong chance of removing paint or chemical blacking behind the spokes. I therefore ground out and polished the frames behind the wheels to avoid this happening. An approximation of the spring shape is also visible as are the holes for the brake hangers. Tim Edited November 16, 2015 by CF MRC 2 Link to post Share on other sites More sharing options...
RMweb Premium CF MRC Posted November 16, 2015 RMweb Premium Share Posted November 16, 2015 (edited) I am now beginning to set up the frames. I have a couple of bits of old Mercontrol brass tube that are made the correct length for frame spacers, holding the two frames together with a greased 14BA bolt through them. These little tubes have seen Stirling service (so to speak) as they started off being used with the Baldwin 2-6-0 and have kicked off quite a few chassis since then. The frames simply have a couple of holes added at each end and are then assembled ready for the PCB spacers to be soldered in. The advantage over the Association jigs is that there is little by way of a heat sink and the main chassis is kept clear of bits, making it easier to work on. The extra frame extension bits with holes can be lopped off once the chassis is assembled. I think the originator of this technique was John Greenwood. The chassis is lined up with sighting rods as can be seen in the photos, any errors are greatly magnified: the out-of-parallel appearance is due to the pin cushion distortions in an iPhone camera. I now need to work out where I want the PCB spacers. Tim Edited November 16, 2015 by CF MRC 1 Link to post Share on other sites More sharing options...
RMweb Premium CF MRC Posted November 17, 2015 RMweb Premium Share Posted November 17, 2015 Continuing the P2 chassis fettling, I carved out the notch for the motor-gearbox: a Maxon 816 with a 1:4 gearbox - shades of Rovex. This drives the third axle with an 18:1 reduction on the worm and wheel gearbox, modified slightly from an Exactoscale design now marketed by C&L. Seventy two to one is a substantial overall reduction, but our engines don't need to run fast on Copenhagen Fields. The combination should wear well. I couldn't resist putting the engine up on its wheels on temporary muffs and also to see how it sits on some tightish radius track. The rear end (bottom of the picture) needs significant tapering, but it has that on the prototype. It won't have a working Cartazzi truck, so there should be plenty of room for side play at this end. The cylinder drains will certainly not survive at the front. The centre pair of axles are a gnats whisker higher than the outer pair, which is how I like it. Tim 11 Link to post Share on other sites More sharing options...
Bulliedman Posted November 17, 2015 Share Posted November 17, 2015 The Salt lake city branch of the Carlson wagon workshop continues at a pace, albeit glacial, with a Harris all steel open and a couple of Bob Jones' 21T hoppers... P1010553.JPG Painting of all wagons in the works is still ongoing. Thanks to a free shipping voucher from Shapeways, and the new FXD material I decided to push the limits of what can be done... P1010556.JPG Yes that's right, 3D printed ground signals for St Ruth (12" WR style disks), its not too bad on first glance and has surprisingly mostly survived the shipping across the country. for comparison, the original design. Fullscreen capture 13112015 182450.jpg I suspect making these work, and attaching a lamp is going to be challenging to say the least. Best Regards, Chris. Hi Chris Where did you get the etched ground signal from ? Andy Link to post Share on other sites More sharing options...
Ian Smith Posted November 17, 2015 Share Posted November 17, 2015 Hi Chris Where did you get the etched ground signal from ? Andy Andy, They will be Chris' own artwork. Just to make sure I checked the photo, and along the edge of the etch you can see his name. Link to post Share on other sites More sharing options...
Atso Posted November 17, 2015 Share Posted November 17, 2015 Continuing the P2 chassis fettling, I carved out the notch for the motor-gearbox: a Maxon 816 with a 1:4 gearbox - shades of Rovex. This drives the third axle with an 18:1 reduction on the worm and wheel gearbox, modified slightly from an Exactoscale design now marketed by C&L. Seventy two to one is a substantial overall reduction, but our engines don't need to run fast on Copenhagen Fields. The combination should wear well. I couldn't resist putting the engine up on its wheels on temporary muffs and also to see how it sits on some tightish radius track. The rear end (bottom of the picture) needs significant tapering, but it has that on the prototype. It won't have a working Cartazzi truck, so there should be plenty of room for side play at this end. The cylinder drains will certainly not survive at the front. The centre pair of axles are a gnats whisker higher than the outer pair, which is how I like it. Tim That looks great Tim! Any chance of a pic or two of the body, pretty please?!? Link to post Share on other sites More sharing options...
RMweb Premium CF MRC Posted November 18, 2015 RMweb Premium Share Posted November 18, 2015 (edited) Here's a picture of the streamlined P2 tender body, Steve. It has a core from an old Foxhunter A1 kit, but the body is a single wrapping of N/S sheet and a new back. The paper pattern used to make the shell can be seen in the picture. I'll put up pictures of the engine body when I've done the chimneys: it's faceless at the moment. Tim Edited November 18, 2015 by CF MRC 2 Link to post Share on other sites More sharing options...
RMweb Gold Donw Posted November 18, 2015 RMweb Gold Share Posted November 18, 2015 A good series of photos on building the chassis. I am intrigued by the gearbox any more details? Don Link to post Share on other sites More sharing options...
Chris Higgs Posted November 18, 2015 Share Posted November 18, 2015 A good series of photos on building the chassis. I am intrigued by the gearbox any more details? Don I think you can buy Maxons (and Faulhabers etc) of all sizes with these incorporated. I've bought a number of bigger coreless motors on surplus stands with geraboxes attached. Not often seen used in 2mm as most of us don't have a loco big enough to fit it in! Chris Link to post Share on other sites More sharing options...
RMweb Premium CF MRC Posted November 18, 2015 RMweb Premium Share Posted November 18, 2015 Actually, the Maxon 816 and gearbox is fitted in our scratch built NLR Parks 0-6-0 tank, Jinty & GN J13 (J52). It's almost a direct replacement of the old Farish armature and bearings. I had originally been a bit wary if using this in a large engine, but it's now a well proven combination on CF after 100's of miles.. It's not so much a case of having a big engine but a big wallet as the £/SF exchange rate is pretty torrid. Tim Link to post Share on other sites More sharing options...
Chris Higgs Posted November 18, 2015 Share Posted November 18, 2015 (edited) Actually, the Maxon 816 and gearbox is fitted in our scratch built NLR Parks 0-6-0 tank, Jinty & GN J13 (J52). It's almost a direct replacement of the old Farish armature and bearings. I had originally been a bit wary if using this in a large engine, but it's now a well proven combination on CF after 100's of miles.. It's not so much a case of having a big engine but a big wallet as the £/SF exchange rate is pretty torrid. Tim Is that the gearbox at CHF 109 (?!). You are not wrong and I don't think its the exchange rate that is the main issue. I think on reflection I won't redesign my chassis etches to fit this combination in :-) Chris Edited November 18, 2015 by Chris Higgs Link to post Share on other sites More sharing options...
RMweb Premium CF MRC Posted November 18, 2015 RMweb Premium Share Posted November 18, 2015 (edited) When we first started using these combinations they were about £60: pricey, but pretty useful. The chassis modifications are very straightforward, so your etches would be perfectly suitable for use Chris. Having cut out / filed the frames on the angle to take the motor with the worm resting on the wormwheel, I cover the chassis side of the motor / gearbox with epoxy resin and a cigarette paper. This is then araldited directly to the frames making sure that the gear mesh is kept st the correct distance as the epoxy hardens. Easy enough to tap off the motor if required done this just once when the axles on the Parks tank wore out! Tim Edited November 18, 2015 by CF MRC Link to post Share on other sites More sharing options...
RMweb Gold Scottish Modeller Posted November 20, 2015 RMweb Gold Share Posted November 20, 2015 Hi all, Well - I'm back into the 2fs modelling again... OK - so I started in 1977 - but time is no mans ruler! Didn't join 2fs at the time as a group of us thought we could do it our own way - how wrong we were! Anyway, I joined 2FS about 4 years ago but appear to have lapsed! Don't have any recollection of a renewal reminder but will take care of that at Modelrail Scotland 2016. Anyway, one of the things that has happened in the meantime is that I created my own model railway society - Scottish Modellers. Out of the group there are 4 of us with an interest in 2fs and we hope to build our own layout. We will try not to upset the 2 fs Scottish Area group though! So - what's on my 2fs Workbench? I decided to start at the very route of the modelling.... Track! I have Easitrack b/h and f/b components that I am starting to put together. With the b/h rail and sleeper bases I get it, and understand it. The head of the rail is the bigger cross section. However, with the f/b rail this is the same and to me it looks wrong when compared to the real thing. When I look at the section comparison (see below) this seems wrong! Am I just being daft? Thoughts, comments appreciated! Link to post Share on other sites More sharing options...
Chris Higgs Posted November 21, 2015 Share Posted November 21, 2015 Hi all, Well - I'm back into the 2fs modelling again... OK - so I started in 1977 - but time is no mans ruler! Didn't join 2fs at the time as a group of us thought we could do it our own way - how wrong we were! Anyway, I joined 2FS about 4 years ago but appear to have lapsed! Don't have any recollection of a renewal reminder but will take care of that at Modelrail Scotland 2016. Anyway, one of the things that has happened in the meantime is that I created my own model railway society - Scottish Modellers. Out of the group there are 4 of us with an interest in 2fs and we hope to build our own layout. We will try not to upset the 2 fs Scottish Area group though! So - what's on my 2fs Workbench? I decided to start at the very route of the modelling.... Track! I have Easitrack b/h and f/b components that I am starting to put together. With the b/h rail and sleeper bases I get it, and understand it. The head of the rail is the bigger cross section. However, with the f/b rail this is the same and to me it looks wrong when compared to the real thing. When I look at the section comparison (see below) this seems wrong! X-Section-of-types-of-Rails.gif Am I just being daft? Thoughts, comments appreciated! Which part of it seems wrong? One thing that is certainly the case is that the FB rail available for 2mm modelling has a foot that is wider than the prototype. Link to post Share on other sites More sharing options...
RMweb Gold Scottish Modeller Posted November 21, 2015 RMweb Gold Share Posted November 21, 2015 Which part of it seems wrong? One thing that is certainly the case is that the FB rail available for 2mm modelling has a foot that is wider than the prototype. Hi Chris, What I thought should be the foot of the rail does not fit the sleeper bases but what I thought would be the railhead does. Hence my confusion! Anyway - could not sleep last night so ended up putting all the rail onto the sleeper bases. Thanks Link to post Share on other sites More sharing options...
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