Quarryscapes Posted December 10, 2015 Share Posted December 10, 2015 I've got 2 of these to build up into Cambrian condition. Can anyone tell me what pitfalls need to be overcome? I've started work on one and it looks like there's going to be lots of trouble getting it all to line up and fit. Link to post Share on other sites More sharing options...
mike morley Posted December 10, 2015 Share Posted December 10, 2015 (edited) Is yours original K's or the later IKB version with the etched chassis? I started but have never finished the latter version. The chassis is exquisite, but I was warned by more than one source that it is quite delicate and nowhere near strong enough for the rough and tumble of exhibition life. Apparently the "cure" is to abandon the built-in compensation and solder it up solid, but I wasn't convinced a rigid chassis could cope with the results of my poor track-building skills, which is why it was never finished. I did seriously consider doing a Cambrian tender conversion and even got to the stage of discussing the possibilities with Kay Butler, but when I sat down and worked it out about the only parts of the kit that would be useable were the boiler fittings and the extreme front end (smokebox, cylinders, etc.) That seemed to be wasting an awful lot of a perfectly good kit (and mine is good, with everything nicely cast and fitting together well) as well as putting a helluva lot of weight right where a 4-4-0 needs it least, so the idea was quietly abandoned. I realise that my findings aren't an awful lot of help but they might prevent you going up a blind alley or two. Edited December 10, 2015 by mike morley Link to post Share on other sites More sharing options...
Quarryscapes Posted December 10, 2015 Author Share Posted December 10, 2015 Both mine have Brass bar frames, one of them has had the frames soldered up, and using those as a datum nothing lines up properly! You can see there that the front frame extension needs to go back a good 1mm, then the smokebox needs to come back another 1mm or so on top of that. I've spent a good few hours this evening opening out the slot in the boiler bottom to slide that forward a little, filing the back of the smokebox front to sit that a little further back and attacking the footplate ahead of the tanks to bring the chassis front backwards. I've also taken off the leading boiler band, so any gap left can hopefully be covered by a new microstrip band. I did also consider the 4-4-0 conversion but there's actually very little of the kit useful for that so like yourself, Mike, that's off the cards for the moment. I'll be doing a new chassis anyway as I need EM, and I want to incorporate the obvious compensation beam behind the drivers. I've ordered the wheels from Ultrascale so am committed to both of them now! The cab doorway seems really narrow - is that really the case? 2 Link to post Share on other sites More sharing options...
mike morley Posted December 10, 2015 Share Posted December 10, 2015 Afterthought . . . The weakest point of the kit is probably the whitemetal crossheads and slidebars. Replacement nickel-silver slidebars would be fairly easy to fabricate, but they would only accelerate the wear of the already unsatisfactory and rather harder to replace crossheads. Any ideas? Link to post Share on other sites More sharing options...
mike morley Posted December 10, 2015 Share Posted December 10, 2015 Here's the IKB chassis. As you see, the axle bushes are fitted to the compensation beam, not the actual chassis, which is lovely but also fragile. Link to post Share on other sites More sharing options...
Quarryscapes Posted December 11, 2015 Author Share Posted December 11, 2015 Here's the IKB chassis. P1000910.JPG As you see, the axle bushes are fitted to the compensation beam, not the actual chassis, which is lovely but also fragile. That's rather nice - does the beam actually do some compensating then? Was thinking of the crossheads issue myself, the whitemetal used being ever so bendy I'm expecting fun fun fun with the crossheads and guides. Theoretically 3D printed lost wax cast brass could be used, but the grade used by the 3d printing folks is very hard, so if they come back with wonky piston rods it would snap rather than straighten. I'm already going to replace the supplied rods since I won't be able to guarantee a match with my etched chassis. (I intend to use comet/brassmasters springy hornblocks rather than the sort that you line up yourself and solder in place as a unit). I've just drawn up a replacement dome to be done in polished brass to replace the whitemetal one. Link to post Share on other sites More sharing options...
mike morley Posted December 11, 2015 Share Posted December 11, 2015 The compensation beam does do the compensating, as per prototype. It does, however, mean that a very high percentage of the loco's weight is carried by the beam pivots. The pivots themselves are quite substantial, but there is very little metal around them on both the chassis and the beams and is probably the cause of the failures. The outer spring hangars are attached only to the compensation beam and are forked to act as guides, the intention being that they keep the compensation beam roughly in line with the chassis. Again, they are not really substantial enough to do the job and any whip they are unable to control adds to the strain on the beam pivots. I am starting to suspect that the only way we're going to get a decent set of crossheads is to file them out of solid brass. If you can get more than one brass dome made, I would like to add it to the etchings for the Sharp's Goods on the shopping list I'm starting to compile with you! Link to post Share on other sites More sharing options...
Horsetan Posted December 11, 2015 Share Posted December 11, 2015 Here's the IKB chassis. P1000910.JPG As you see, the axle bushes are fitted to the compensation beam, not the actual chassis, which is lovely but also fragile. Would it not be possible to convert to the High Level Models CSB system? Link to post Share on other sites More sharing options...
mike morley Posted December 11, 2015 Share Posted December 11, 2015 Not really. About the only bit of the original set-up that could be re-used would be the compensation beams as cosmetic items. The rest would be a scratchbuild. Link to post Share on other sites More sharing options...
Quarryscapes Posted December 11, 2015 Author Share Posted December 11, 2015 Looks an interesting chassis design! Mine will use the compensation beam and cosmetic springs to act as keeper plates for the hornblocks. I need to find a way of making the pony truck pivot length adjustable to take into account of the variation in the castings, Bit of angle and a screw over a spring should do it I think, adjustable from the front of the loco with a well aimed screwdriver! Mike, I've uploaded the dome to Shapeways as a pair, much more cost effective that way though still pretty eye watering for the size of the item. I've sized them to take into account shrinkage , but have left a very chunky 0.8mm thick flange so as not to lose a scale size one in the casting or polishing stages, easily filed back down to thickness anyhow. https://www.shapeways.com/product/2NUT76TSK/metropolitan-4-4-0t-dome-4mm-scale?optionId=58623878 A thought occurred to me about the crossheads etc. How about making the slidebars up from angle? That way the crosshead could be made massively oversize for strength yet it would not appear to be so from the outside. Similar to deWinton cylinder blocks which have the slidebars cast integral, the whole lot is turned on the lathe so everything lines up perfectly - could do something similar here perhaps? Link to post Share on other sites More sharing options...
mike morley Posted December 11, 2015 Share Posted December 11, 2015 Mike, I've uploaded the dome to Shapeways as a pair, much more cost effective that way though still pretty eye watering for the size of the item. I've sized them to take into account shrinkage , but have left a very chunky 0.8mm thick flange so as not to lose a scale size one in the casting or polishing stages, easily filed back down to thickness anyhow. https://www.shapeways.com/product/2NUT76TSK/metropolitan-4-4-0t-dome-4mm-scale?optionId=58623878 They are seriously expensive! Would it bring the price down from the stratosphere if they were unpolished? Link to post Share on other sites More sharing options...
Jeff Smith Posted December 11, 2015 Share Posted December 11, 2015 I built the IKB one some years ago in P4. I assembled as per the instructions and of course the motor has to be on the forward main driver axle and therefore requires space for movement within the boiler. Because of the weight distribution the bogie must be weight bearing - I just assembled mine solid and used the central pivot slotted to give a little sideplay; the chassis can be levelled by adjusting the bogie height. This is of course far superior to the RTR 4-4-0 solution of making the chassis with all the weight on the main drivers and the bogie just going along for the ride.... I used the white metal motion but the loco is not run enough to suffer from wear. As I recall the castings all went together well. Here is a picture of the underside - as you can see the motor and flywheel are a snug fit but there is a few mm of space for movement. Also I used spacers on the rear driver axle to keep the compensation beams parallel not just relying on the cosmetic springs. 5 Link to post Share on other sites More sharing options...
mike morley Posted December 11, 2015 Share Posted December 11, 2015 I used spacers on the rear driver axle to keep the compensation beams parallel not just relying on the cosmetic springs. Probably the key comment in a posting that was very helpful all round - thank you. From looking at the underside view, am I right in thinking you've also beefed-up the compensation beam pivots with some nuts and bolts? Link to post Share on other sites More sharing options...
Jeff Smith Posted December 11, 2015 Share Posted December 11, 2015 Mike - I can't remember what the original chassis design used for pivots.... I also remember that I had to loosely restrain the motor to prevent the flywheel touching the inside of the boiler. Link to post Share on other sites More sharing options...
Quarryscapes Posted December 11, 2015 Author Share Posted December 11, 2015 They are seriously expensive! Would it bring the price down from the stratosphere if they were unpolished? It's about 30% cheaper unpolished. I'm going to see how much more hollowing out I can do to it though! I've also drawn up some replacement slidebars: https://www.shapeways.com/product/TJF4JGY6H/ https://www.shapeways.com/product/KEXXHYWH7/ Might be fun to assemble since the crosshead needs to go in through the side, could always chop it up and slide it in through the back, but I didn't want to remove the bracing or it'll likely end up with slidebars all facing different directions after casting. 1 Link to post Share on other sites More sharing options...
Quarryscapes Posted December 11, 2015 Author Share Posted December 11, 2015 I built the IKB one some years ago in P4. I assembled as per the instructions and of course the motor has to be on the forward main driver axle and therefore requires space for movement within the boiler. Because of the weight distribution the bogie must be weight bearing - I just assembled mine solid and used the central pivot slotted to give a little sideplay; the chassis can be levelled by adjusting the bogie height. This is of course far superior to the RTR 4-4-0 solution of making the chassis with all the weight on the main drivers and the bogie just going along for the ride.... I used the white metal motion but the loco is not run enough to suffer from wear. As I recall the castings all went together well. Here is a picture of the underside - as you can see the motor and flywheel are a snug fit but there is a few mm of space for movement. Also I used spacers on the rear driver axle to keep the compensation beams parallel not just relying on the cosmetic springs. I saw some pics of this whilst researching, it looks great! What motor and gearbox combo is that in there? I was thinking of a Highlevel loadhauler compact+ as I'll be needing shunting speeds from mine. What kind of radius will it get round with in that configuration? Link to post Share on other sites More sharing options...
Jeff Smith Posted December 11, 2015 Share Posted December 11, 2015 I bought the kit at Scaleforum at least 20 years ago. I remember going to different traders for the wheels, Sharman I think, and the motor, Branchlines maybe! As regards radius, it works on my P4 turnouts but I will have to check when I get home after the weekend as to the type. Link to post Share on other sites More sharing options...
Quarryscapes Posted December 16, 2015 Author Share Posted December 16, 2015 Well here's mine so far... There was a minor disaster, I built the cab as a sub assembly, all soldered up and cleaned and fettled for a perfect fit. When it came to actually soldering it down one of the wings on the rear sheet snapped off! Refitting it has led to the extra rivets seen in the close up! (blobs of solder) Construction is 100% soldered, a good opportunity to play with my new Temperature controlled Iron - although described as 75W I'm not sure it gets anywhere near that, even small castings suck all life out of it and extreme patience is required. 4 1 Link to post Share on other sites More sharing options...
Horsetan Posted December 16, 2015 Share Posted December 16, 2015 I bought the kit at Scaleforum at least 20 years ago. .... That sort of explains why it's no longer produced. Link to post Share on other sites More sharing options...
Bluebell Model Railway Posted December 16, 2015 Share Posted December 16, 2015 Indeed, been after one of these for a while posted a few months ago, missed out on an ebay one sadly think that was a K's kit, coming along nicely and shame they are no longer available. Link to post Share on other sites More sharing options...
Quarryscapes Posted December 17, 2015 Author Share Posted December 17, 2015 (edited) Indeed, been after one of these for a while posted a few months ago, missed out on an ebay one sadly think that was a K's kit, coming along nicely and shame they are no longer available. Was it recent? That may be the one that just dropped through my letterbox, sorry! Might crack on with it shortly now the above one is as complete as I can make it without the 3D printed bits arriving and the new chassis. Doesn't look too bad I don't think, there are a couple of issues - whoever had started building it before me has got the cylinder angle slightly wrong, hence the gap under the smokebox wrapper. They also managed to get the rear bunker assembly twisted. I think they used full temperature solder, I couldn't persuade it to melt at any whitemetal safe temperature anyhow so I'll just have to live with it. One of the cab steps is missing too, so I will fabricate one. I'm not sure which tank fillers to use for the Cambrian version, all photos I have are from trackside and tank tops aren't visible. Likewise what to do with condenser pipe holes? Anyway, here's how it looked at close of play yesterday, resting on it's soon to be scrapped 00 chassis. Edited December 17, 2015 by Quarryscapes 2 1 Link to post Share on other sites More sharing options...
Quarryscapes Posted December 17, 2015 Author Share Posted December 17, 2015 Pulled my finger out today and made a start on the chassis. Fortunately a low res GA drawing is available online and is plenty good enough for getting the profile. The build so far was weighed on some scales to get an idea of balance - 144g on the leading drivers and 61g on the rear, not taking into account any effect of the Pony truck. This was then roughly worked out to get the spring heights for the Brassmasters/Comet springs. It'll probably all be wrong, but at least the cutouts will be in place to enable high level hornblocks or some such to be fitted instead. 1 Link to post Share on other sites More sharing options...
mike morley Posted December 17, 2015 Share Posted December 17, 2015 I'm not sure which tank fillers to use for the Cambrian version, all photos I have are from trackside and tank tops aren't visible. A common Cambrian problem, I'm afraid. For instance, I have yet to find a picture of Seaham tank "Gladys" in her later guise as GWR 1196 taken from a vantage point high enough to identify the location, nature or even existence of its tank vents. Yours looks good so far. Was the problem with the angle of the cylinders due simply to less-than-perfect workmanship by the original builder or is it one of those areas where the nature of the beast means you cannot be sure you've got it right until you're already past the point of no return? This thread is tempting me to resume work on my stalled version. One reason for keep on putting it off is sheer cowardice - the knowledge that it is irreplaceable if I make a hash of it having induced something close to a phobia about tackling kits that are no longer available. Where whitemetal kits are concerned it does not help that my beloved 15watt Weller, inherited from my father and probably not much younger than me, has finally expired and I do not get on nearly as well with either its Antex or modern Weller replacements. Link to post Share on other sites More sharing options...
mike morley Posted December 17, 2015 Share Posted December 17, 2015 I was still typing #23 when you posted #22! Having read #22, my immediate reaction is that the extreme weight imbalance will cause major problems getting the springing right and will probably need huge amounts of experimentation that would probably take quite some time while you sourced springs of differing strengths with which to experiment. I would, therefore, suggest that this might be an occasion where compensation is the better and certainly the easier route. Link to post Share on other sites More sharing options...
Jeff Smith Posted December 17, 2015 Share Posted December 17, 2015 I agree, both my 4-4-0 locos have twin beam compensation with weight on the bogies, although the NL one has a compensated bogie as well. Quarryscapes, have you figured out the motor and g/b arrangement yet? Link to post Share on other sites More sharing options...
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