TurboSnail Posted March 21, 2019 Author Share Posted March 21, 2019 The Sharpie is coming along nicely, a lick of paint does a lot to make a project feel more finished. One nice feature of the scale-link wheels is that the plastic centres can be pushed out for painting, so everything stays nice and neat. 12 2 Link to post Share on other sites More sharing options...
TurboSnail Posted March 26, 2019 Author Share Posted March 26, 2019 I've been working most evenings for the last week on getting the Sharpie's conrods to work without binding - I've come close a couple of times, but never quite got it. However, tonight I tried opening up the holes in the chassis so the bearings are a bit loose, then assembling it without gluing the bearings in and for some reason I can't explain, that seems to work much better. Now to add pickups and get it running under its own steam. I'm also about to try a different method of motorising a chassis to get around the whole conrods issue. I think I need to sort my chassis construction out before designing any more locos. 2 Link to post Share on other sites More sharing options...
RMweb Gold Corbs Posted March 26, 2019 RMweb Gold Share Posted March 26, 2019 As you've got square holes in the wheels and square ends on the axles, is the issue the wheel not sitting perpendicular to the axle, rather than the quartering being off? Is the wheel oscillating as it turns? Link to post Share on other sites More sharing options...
TurboSnail Posted March 27, 2019 Author Share Posted March 27, 2019 10 hours ago, Corbs said: As you've got square holes in the wheels and square ends on the axles, is the issue the wheel not sitting perpendicular to the axle, rather than the quartering being off? Is the wheel oscillating as it turns? Possibly, the wheels aren't far out and the quartering looks fine. But I'm, pretty sure it's the conrod lengths that's the issue as you can physically see the conrods bowing out at certain points on the revolutions as they are too long. But adjust the bearing and they stretch instead as the tolerance is so tight. Link to post Share on other sites More sharing options...
RMweb Gold Corbs Posted March 27, 2019 RMweb Gold Share Posted March 27, 2019 Have you tried reaming out the holes in the rods themselves? Lots of chassis I've seen have a bit of play in them to account for that. Link to post Share on other sites More sharing options...
TurboSnail Posted March 27, 2019 Author Share Posted March 27, 2019 17 minutes ago, Corbs said: Have you tried reaming out the holes in the rods themselves? Lots of chassis I've seen have a bit of play in them to account for that. I haven't, the holes are 1.6mm diameter and the crankpins are 1.5mm, so there's virtually no play at all. Since the chassis is actually running ok at the moment, I don't want to touch it, but if it starts binding again, I'll give that a go. Link to post Share on other sites More sharing options...
Killian keane Posted March 28, 2019 Share Posted March 28, 2019 Thats a nice looking sharpie, Ill have to get one off you at some point 1 Link to post Share on other sites More sharing options...
Ruston Posted March 28, 2019 Share Posted March 28, 2019 On 26/03/2019 at 22:14, TurboSnail said: I've been working most evenings for the last week on getting the Sharpie's conrods to work without binding - I've come close a couple of times, but never quite got it. However, tonight I tried opening up the holes in the chassis so the bearings are a bit loose, then assembling it without gluing the bearings in and for some reason I can't explain, that seems to work much better. Now to add pickups and get it running under its own steam. I'm also about to try a different method of motorising a chassis to get around the whole conrods issue. I think I need to sort my chassis construction out before designing any more locos. The way to do it is to fix the bearings in the frames and then open out the holes in the bearings, not open out the holes in the frames. Are the rods running directly on the crank pins, or do you have bearings in the rods? Link to post Share on other sites More sharing options...
Caley Jim Posted March 28, 2019 Share Posted March 28, 2019 It's also worth putting a length of rod, the same diameter as the axles, through the bearings while you fix then. That way both bearings will be perfectly aligned. Jim Link to post Share on other sites More sharing options...
TurboSnail Posted March 28, 2019 Author Share Posted March 28, 2019 2 hours ago, Ruston said: The way to do it is to fix the bearings in the frames and then open out the holes in the bearings, not open out the holes in the frames. Are the rods running directly on the crank pins, or do you have bearings in the rods? Now that would have been sensible... At least I know for next time! I should probably also buy myself a tapered reamer for this, rather than relying on drill bits. The rods have tiny sections of brass tube in to act as bearings. 1 hour ago, Caley Jim said: It's also worth putting a length of rod, the same diameter as the axles, through the bearings while you fix then. That way both bearings will be perfectly aligned. Jim The shank of a 3.2mm drill bit seems to work pretty well for this, I've found. Link to post Share on other sites More sharing options...
Guy Rixon Posted March 28, 2019 Share Posted March 28, 2019 If the coupling rods seem to be the wrong length, but only for part of a revolution, then I suspect that one of more of the crankpins are out of true. I can't see how else you'd get a variation. 0.1mm clearance on the crankpins doesn't sound that tight to me. IIRC, it's at the extreme upper end of the recommendation for custom-built chassis. Were the axle bearings set up with jig axles? Given that allowing the bearings to drift in the frame has helped, I predict that setting them to match the coupling rods using jig axles, then fixing then, would also help. London Road Models sell jig axles; they are cheap. 2 Link to post Share on other sites More sharing options...
TurboSnail Posted March 28, 2019 Author Share Posted March 28, 2019 Thanks all for the responses - what I'm taking from all this is that I need to invest in some proper tools! Link to post Share on other sites More sharing options...
TurboSnail Posted March 30, 2019 Author Share Posted March 30, 2019 I was just flicking through Russell's book on Southern Railway Locomotives and found the LSBCR D1 0-4-2T, and now I can't shake the feeling that I want one. It does feel a bit wrong though, being a South Eastern boy. In 4mm, SEFinecast do a whitemetal one, and Albion do an etched one (though I can't find a supplier), but I'm wondering if I should CAD up my own version... Or maybe I should just stick to the things I've already said I'll make! 2 Link to post Share on other sites More sharing options...
RMweb Premium Northroader Posted March 30, 2019 RMweb Premium Share Posted March 30, 2019 They did run on air brakes, meaning that they could operate the controls for push pull trains on the LBSC system which the SR standardised, in preference to the mechanical linkage systems on the Western and Eastern Divisions, so D1s did turn up on Eastern Div. pushpulls. 2 Link to post Share on other sites More sharing options...
TurboSnail Posted March 31, 2019 Author Share Posted March 31, 2019 A bit bored this afternoon, so I've just made a start on another loco for the Electrotren chassis. I needed something to act as a slightly heavier shunter on my planned layout, so something from the imaginary Hudswell Clarke catalogue will do nicely. 4 Link to post Share on other sites More sharing options...
burgundy Posted March 31, 2019 Share Posted March 31, 2019 On 30/03/2019 at 13:42, TurboSnail said: …..LB&SCR D1 0-4-2T, and now I can't shake the feeling that I want one. It does feel a bit wrong though, being a South Eastern boy. In 4mm, SEFinecast do a whitemetal one, and Albion do an etched one (though I can't find a supplier), but I'm wondering if I should CAD up my own version... You can usually get the Albion kits through Roxey Mouldings and they make up very well. A pity to produce a triplicate when there are so many of Mr Craven's engines just begging to be modelled. Best wishes Eric 1 Link to post Share on other sites More sharing options...
TurboSnail Posted April 1, 2019 Author Share Posted April 1, 2019 (edited) Since I couldn't use a pre-made pickup on the back wheels of the Sharpie, I've improvised with some phosphor bronze sheet. Soldering the lot together and it runs, pretty nicely too. The video is of a test on fixed 3v DC as I don't have a proper controller with me at the moment. Edited April 1, 2019 by TurboSnail Added video 6 4 Link to post Share on other sites More sharing options...
TurboSnail Posted April 2, 2019 Author Share Posted April 2, 2019 The "Hudswell Clarke" is coming along nicely, it's fun being a freelance loco designer I'm no expert on this type of loco though, so please do feel free to point out anything that looks a bit wrong. 5 Link to post Share on other sites More sharing options...
sem34090 Posted April 4, 2019 Share Posted April 4, 2019 Personally, I think the bottom of the bunker tapers in too close to the back of the cab - you would fit little more than coal dust down there. Giving the bunker just a little more depth would cure that. 1 1 Link to post Share on other sites More sharing options...
RMweb Gold Regularity Posted April 4, 2019 RMweb Gold Share Posted April 4, 2019 1 hour ago, sem34090 said: Personally, I think the bottom of the bunker tapers in too close to the back of the cab - you would fit little more than coal dust down there. Giving the bunker just a little more depth would cure that. The bunker may protrude into the cab, though: they often did. Link to post Share on other sites More sharing options...
TurboSnail Posted April 4, 2019 Author Share Posted April 4, 2019 My Industrial Fox Walker has the bunker going into the cab at the bottom - I do need to draw the inside bit in the cab though if I'm not going to extend it outside. 2 Link to post Share on other sites More sharing options...
TurboSnail Posted April 5, 2019 Author Share Posted April 5, 2019 (edited) As a follow up on bunkers; the Fox Walker with the bunker protruding into the cab, and the mods made to the "Hudswell Clarke". As an added benefit, it gives the enginemen somewhere to put their tea and/or bacon sandwich. And no, I'm not going to be modelling a 4mm scale mug... Edited April 5, 2019 by TurboSnail 4 2 Link to post Share on other sites More sharing options...
TurboSnail Posted April 5, 2019 Author Share Posted April 5, 2019 Some nameplates arrived from Narrow Planet today, so I've finally finished off the Neilson 2-2-2T, including a driver, coal and some basic weathering. So here it is, in the guise of KCL no. 7, 'Earl of Kent'. Apologies for the photo quality, my room is rather dimly lit, which doesn't help my modelling efforts! 10 4 Link to post Share on other sites More sharing options...
Edwardian Posted April 5, 2019 Share Posted April 5, 2019 Superb. I have much to try to live up to here. 1 Link to post Share on other sites More sharing options...
TurboSnail Posted April 7, 2019 Author Share Posted April 7, 2019 As a heads-up, I'm planning to run a livestream tomorrow (Monday) night from about 8:30. Likely to include a new loco build, more work on finishing my Sharp Stewart 0-4-0st and a look at the smallest loco I've ever made (if it can be called a loco...). Maybe also throw some ideas around about possible new loco/coach/wagon designs. Channel link here: https://www.youtube.com/channel/UCTbnvrbj9PKn5AcnzmwRo2w?view_as=subscriber 3 Link to post Share on other sites More sharing options...
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