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D869

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  1. I'd suggest starting with a rewheeled 'N' loco and saving the full loco kit build until later. Then you will have something up and running quickly with which you can test your track and electrics.
  2. Could you do the black circles with a fine marker pen with the wheels turning in a lathe/drill/loco ?
  3. Good stuff Pix. Glad you are keeping up the work rate. I especially like the DMU nose - always good to see how people tackle tricky design issues and those cab window surrounds coinciding with the angles on the nose definitely come into that category.
  4. I reckon if you shift over to a different L&B then you will keep the RTR folks at bay for a while longer https://www.youtube.com/watch?v=ZjBKQlr9fSs The donkey at 1:12 is *NOT* happy! I do like a tin turtle too Oh... don't mind me... the randomness is quite an accurate reflection of the contents of my real workbench anyway.
  5. Thanks Tim and thanks for the postings about your loco builds which have definitely helped me with the O2. I do like a bit of L&B and am particularly glad that a short stretch has reopened and we can ride in restored coaches and admire the Exmoor scenery. I like my own narrow gauge models in 16mm scale with actual steam though
  6. You have the 16T kit from the Association - plastic body and etched chassis. Personally I'm a fan of this kit and have built several of them in different variations (top doors or not, bottom doors or not, different brake designs etc.). I generally scrape the insides of the sides to taper them a bit so that the top edges look thinner and add some 5 thou plastikard fillets on tops of the corners to complete the corner strengtheners. The slots in the sides are a nice touch. I'm not 100% sure about their later condition but I suspect you should probably delete the tiebars between the axleboxes. The chassis that comes with the Association kit covers several options including vac fitted china clay opens, hence the tiebars and 4 brake shoes when you probably only need two for a 16 tonner... but again check what the later survivors looked like because I'm more au fait with their earlier condition.
  7. Gosh... five! That's a vote of confidence. I hopefully have one on the way with completely wrong bogie centres which will need some stretching. Ian Morgan's post on t'other thread reminded me of another thing... I wonder if we will get to pay extra for import taxes and then service charges on top to for the privilege of having said taxes collected from us. I've had that happen before now with an order from the US but it seems pretty random.
  8. From https://en.wikipedia.org/wiki/British_Rail_Class_121 - 8'6 bogies and 46'6 pivot centres I notice they have some Green Max in stock too. Historically this brand had better answers for 1st gen DMUs. The product numbers seem now to be in the 57xx range and most of the listings dont quote the bogie wheelbase but maybe there is hope for a 17mm or 17.5mm wheelbase bogie one day? ... or maybe they have moved on to making GWR Pannier tanks now?
  9. MinerChris needed to install a replacement Tramfabriek motor in his 122 to get it to run properly. They seem to do quite a trade in them so maybe factor two new motors into your sums
  10. Lovely job Jim. Good to see it is now in revenue earning service. Onwards to the next project now then
  11. Stephen Harris' kits are excellent. As you say they are 2mm scale. That is a 3% size difference from British 'N'. Unless you have an identical vehicle to 2 1/16 mm scale alongside then you are unlikely to notice... and with wagons I suspect you'd be pushed to tell even if you did have two identical ones. The Association shop also does a number of BR era wagons... it just depends how 'modern' is your idea of 'modern'. http://2mm.org.uk/products/shops.php?shop_num=2 You will also need some 2-027 wheels from the shop to go under your kits - these are 'N' profile but have the right axle length for the kits.
  12. Brakes... I knew this was going to be quite an involved job and sure enough it was... and so is this post (sorry!) The O2 brakes are pretty prominent and even the cranks by which they are driven are on full display. MinerChris does have one of Mr Higgs' chassis etches in his gloat box so I could have pinched the brake etches from that but that seemed rather a waste. The Dave Holland keeper plate design complicates matters because the brakes must be removeable if the wheels are also to be removeable. I spent a whole evening just thinking about how to make all of this fit together. The eventual design is pretty similar to the one recommended in Pete Wright's book but I did consider two alternatives before arriving at this. The key 'lightbulb moment' was the idea to solder short lengths of 0.5 x 0.3mm tube into the brake hanger pivot holes in the frames. This gives just over 1mm of length for location and support rather than relying on just the 0.5mm thickness of the frames. Spoiler alert... the finished article Before starting on the real thing I made a fairly basic test piece to find out if it was actually possible to solder this thing together and also to see if the hangers could be poked up behind the coupling rods when assembing the chassis. This was a very useful exercise, apart from proving that I could put the thing together it also showed me that I needed to make the hangers longer by 0.5mm to avoid the pull rods fouling the coupling rod bosses at bottom dead centre. The pull rods are 0.4mm MSE point rodding strip. Height-wise this is pretty much spot on with the GA drawing but no doubt the real things were not square in profile. They are also nice and strong. A couple of pieces were soldered with some temporary plain rail spacers at the correct spacing. The cross pieces are 36SWG phosphor bronze bent into an 'L' and soldered behind the pull rods. For the hangers I made a drilling jig using the MF70 to get the hole spacing correct and then drilled some 1mm wide scrap etch and filed it to the general outline. 36SWG wire was soldered in for the top pivots. Having taken a break from CNC for the hangers I decided that manual filing was overrated and went back to CNC for the other bits. Because of the tiny parts involved the blank was soldered to a backing plate rather than relying on sticky tape. One of them still came unstuck though (lack of solder coverage). An O2 brakes kit... Soldering the shoes onto the hangers involved a bit of trial and error and some swapping things around on the final assembly to find the best combination. The assembly was then fitted to the chassis and the hangers soldered to fix them to the cross shafts. Some aluminium hairgrips were used as heatsinks to prevent the cross shafts coming unstuck from the pull rods. Some small bits of 0.4mm PCB were gapped and used to join the cross pieces in the middle. The temporary spacers could then be removed. Which just left the connections to the cranks to sort out. On the real thing these have an adjuster so I wanted to represent that. I used some bits of 5 thou N/S strip that I bought very cheaply many years ago and am now running out of. This was bent around a drill and 0.4mm brass wire soldered into the 'U' for the 'pin' into the crank. In fact this is just soldered to the face of the crank rather than being pinned. Once cut to length the adjuster will quite happily grip the pull rod, can be adjusted to line up with the crank and will stay put while being attacked with a hot soldering iron. Nice . The photo was taken before soldering. I got a bit silly with the bosses at the ends of the cross pieces. These are 0.8mm brass rod with a the end filed down to leave just a 0.2mm thick sliver to sit on top of the pull rod. A 0.5mm-ish disc (plus the 'sliver') was parted off in the watchmaker's lathe and the resulting bit soldered onto the pull rod (heat sink deployed again). I think I must have made at least 8 and failed to file the 'sliver' several more times. Once attached to the pull rods, the bosses were filed back to about 5 thou thickness. Once all was assembled the loco was taken for a test run through South Yard's 'interesting' radius pointwork. It made it through but there was some 'rock and roll' due to a clearance issue. Can you spot it?
  13. I'm not so sure. My (early) Hymek notes say that the wormwheel is 5.8mm OD and has 20T. This doesnt work out to a whole mod number but maybe that is the 'fudge' to allow it to pivot. The spur train in the bogie works out to mod 0.3 from my measurements - the wormwheel moulding is a compound gear giving reduction between the wormwheel and the spur train.
  14. I'm not sure how you would get the quartering 'in sync' with 3 axle gears. if your axles fit the bearings well and the crankpins fit the rods well then having a gear on just one axle is the usual approach. RTR models with fully geared wheels usually have tons of play around the crankpins which may be an option... but once you open the holes out you can't close them up again so I'd treat this as a last resort. I've usually had to tweak the quartering a little after using the quartering tool. It's still worth using because it presses the wheels into the muffs squarely but don't assume that the quartering will be perfect.
  15. I've never had much success in getting wheels out of muffs non destructively. Most folks think it's better to trash the muff and avoid any risk of damaging the wheel. Sounds like you have a methodical approach. We're probably repeating ourselves but check for machining burrs on the gears (and file them off if you find any) and also make sure that the gears are not catching on anything at some point in their rotation - both of these things will mess up your running in potentially intermittent ways.
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