97xx

Not that I think you need any encouragement Ray, but this was an effort I made in my Dad's garage when I was 14 (in the 1970s), using hacksaws, files, hand-drills and I even recall soldering using a Tilley with a soldering iron bit! Cheated with rolled plasticard boiler and firebox made from sheets (you can see it delaminating now). Smokebox door fashioned from car filler, and pin used as door hinge. Whistle and filler caps and vents fashioned from brass rod in electric drill. Two photos: one as originally made with coupling rods cut from tin can and terribly basic pony trucks (sheet with U of plastic channel stuck on to hold axles) second with Lockdown Mods of new wheels, rods and milled brass pony trucks. Chassis was paint-stripped and all blackened chemically. Aside lockdown prompting me to get it out and look at it again, major reason was that it ran horribly - a long 2-4-2T with short wheelbase was a TERRIBLE choice to scratch build - it yawed and nodded badly as it ran along, so new pony trucks have piano wire centring springs added, plus all the (completely unnecessary) sideplay in wheelsets has been removed. Embarrassingly crude to look at but a great runner now and not too many about in 00...

I've had similar issues with loco wheels - I tried to rewheel a 40-year old scratch built chassis (which had a dodgy mazak-centred Romford) with AG ones. The dodgy Romford(s) was/were very obvious as it is a longish-overhang 2-4-2T and it nodded/yawed royally! But try as I might - using a milling vice to push the AG wheels on slowly with a support to ensure the axle was square at the start - it did not work. Made sure the axle ends were burr-free and all of that. The vice would put them on the axle and it was all, obviously dead square/parallel, but as soon as I undid the vice and took the wheelset out and rolled it along a flat it was very evident it was 'wobbly'. If i then pulled one wheel off, set the 1/8" axle with remaining wheel in the mill and tested it, it was wobbly. There was/is something about these wheels achieving their 'own set' on the axle which I couldn't get to stay square. Tried all manner of teasing them straight: (a) not pushing them fully on, resting them, then easing up to the B2B (b) pushing them on a tad further then jigged up the wheelset and tried to tease them out to B2B (c) using super slippery grease on the axle end in the hope that this would stop any 'grab' of the plastic No good. Nodding donkey chassis! I wonder if (c) might have worked straight off, as doing it last may be pointless if I've already 'damaged' the plastic centre. I figured if it had worked, I could let them 'rest' and could probably tease the grease out with brake cleaner afterward, but I doubt that whole process is ideal. Went to a new set of Romfords and loco is completely satisfactory. The run out is tiny. Clearly many use AG but they don't work for me. Pity as they were of more prototypical design, but the trueness is more important to me. As an aside, I found the steel tyres sparked quite a lot with brass pickups. EDIT: I am rebuilding a Q1, and have gone for Romfords all round. I've got however a set of AG tender wheels spare so I will give them a try and report back how they compare with the Romford ones.

Yes that was my immediate thought - although my Dublo/Wrenn ones are a bit thicker!

Would anyone recommend that I put the effort in to compensate an 00 tender? If so, does it matter whether I fix the front or rear axle? Or shall I simply make sure I build it dead square and provide a small amount of float on the middle axle? FWIW, I do intend adding pickups to the front and rear wheels. The etch chassis I have (usual U-folded) is designed & supplied for 2mm axles straight through the etch. The engineer in me would prefer to put bearings in, but again is this overkill? If i did compensate it, would it be considered unacceptably sloppy to slot the axle holes rather than install horn blocks? (...ducks...) Sorry - lots of Q's but an engineer trying his hand at building small things!

Ah thanks Kevin, so Mallard became Blacksmith or vice-versa?

Could anyone point me in the right direction for details of the above? I've acquired a Blacksmith's models 00 kit, and pretty much all I know is that this diagram was converted from steam railmotors. I'm British Railways period and so I would need to model it in that era - did they actually last that long and if so what liveries/numbers did the run? JH Russell only shows them in GW era. If it's not suitable for 1948-on, I will happily move it on to someone who wants one of these seemingly quite rare beasts! Thanks.

Great, thank you. Yes, good point re additional potential error with a knuckle - which usefully reminds me not to cut the rod etches until after I have used them on the chassis jig as axle spacing guides.

I have a set of double-layer etched N/S rods for a 6-coupled loco to fabricate, in 00 gauge. I will have one (rear) fixed driven axle and intend to compensate the front two with hornblocks and a wire and tube typical arrangement bearing on the axles. Currently the rod etches are not cut into two rods (so you could solder them up as single solid rods if you had flangeless centres wheels). Could someone advise me whether it is best to articulate: By having a halved joint at the crankpin (and thus a 'dummy' rivet at the 'real' point of articulation), or, Using the 'real' joint point as the articulation using a rivet? Everything tells me to do 1 as this will be stronger if less truly prototypical. However, I'm sure that this is a well-trodden path for the experts... Thanks!

Thanks all. I can appreciate I’m at risk of a Frankenchassis here so will reconsider my approach. As an aside the problem with the firebox etches is that there are holes in the frames through which the firebox is visible, right in line with CSB wire.

Yes I understand that - which leads to my assertion that it's basically half of 2/3 unsprung loco weight on each sprung axle (let's assume it's equally balanced and equally spaced for simplicity). However, with a fixed axle there is no deflection, and it's this that is troubling me. So if I apply what I've just said to a 4-coupled sprung pair of axles with a rigid rear, the loco will attain a slightly nose down stance if the wheel centres are in line when unweighted. Intuitively I'd say that I need to actually drop the front and centre axle centres versus the rear by the amount of compression I calculate I will get, so that they sit level when all three axles are on the track.

Sorry if I'm being dense, but I can't actually find any calculations or worked examples for on 0-6-0 with one driven fixed axle. Unless, as I hinted, you treat it as an 0-4-0 with 2/3 the total unsprung weight split equally (or in whatever proportion you believe it is) on the two sprung axles?

Do you have a link to the page with the explanation/calcs (not just images) - can't seem to find it.

Good, thanks that's helpful. Needless to say the single pivot design is appealing as I may be tight on front frame overhang to locate the front of a 3-pivot far enough out. I've also plenty of spring wire to choose from if I need to tweak the compliance/set. Will read up more on clag - seems there is a mass of interesting guidance there.

Good input, thank you. Yes, 00, sorry - quite important... I've gone for a high motor mount and reduction box - yes keeps it well clear of the frame gubbins, gets the motor back over the centre wheels (weight and CofG wise) and the boxy Q1 lends itself to that nicely. I will indeed be articulating the rods - should have said that - and the double etches lend themselves to that. Interesting on sideplay, my calcs initially came up with a larger requirement, but then I realised that there is a fair bit of flange to rail clearance given the 00 B2B dimensions. I've designed the CSB pivot dimensions/spacing using the S4 calculators, and currently have it with ca. 0.4mm 'set' on each axle using 00 handrail wire. Ideally, I would do 3-axle, but I'd rather go front and middle which work as opposed to spoiling my first attempt trying to shoe-horn it all in past the back axle/box etc. If I go for a 2-axle CSB, how do I run the calculations? Immediately, I'd assume use 2-axle calculator, with two-thirds of the loco mass (as it was almost equally spread) applied 50% to each of the 2 axles? However, with a fixed rear, that doesn't smell quite right surely as the middle axle moment will now be 'derated' by the distance from the fixed rear? Sorry if this is a silly Q, but perhaps it demonstrates that this is my first go. Finally, I would concur that this probably isn't necessary fr a simple 0-6-0 in 00 but the large natural weight of a white metal body and the fact I HAVE to rebuild it all simply presented an opportunity to challenge myself. See this thread for another unexpected 'challenge'...

Am rebuilding a rather tatty Keyser's Q1, and decided to go for a SEF etched chassis plus a High Level gearbox to take a Mashima. Fancying a bit of a challenge, I then decided to I'd like to compensate it. Having never done this before. I have gone for High Level CSB and hornblocks. I have three questions: 1. Should I 'fix' the rear axle, make it the driven one, and then compensate the front two only? Much as I'd like to boast a fully compensated chassis, a contributory factor is that the chassis has firebox etches soldered to its inner faces - all of which makes fitting a CSB spring wire very tight/awkward/impossible between those and a gearbox) 2. To ensure that any compensation 'works', I assume that the coupling rod holes need to be oversize to allow for the effective extension in the wheelbase as the axles slide vertically in the hornblocks? 3. I need the loco to negotiate 2' radius curves. The frame width will be around 12.2mm. The rear axle (whether fixed or not) will have be shimmed to have minimal sideplay as it's driven. I'd appreciate views on allowable/permissible/necessary sideplay on the 1st and 2nd axle? If it has any influence, it would seem that the weight distribution will be pretty equal across the axles. Thanks!

Is the HD Technical Manual still available? If so, could someone provide me with contact details? (I did find the MKN site, but believe there is a UK contact? Thanks

Am contemplating rewheeling an 0-6-0 chassis which is the basis for my K's Bodyline 97xx. Yes, I appreciate it's wrong wheelbase etc., but I'm not going to scratchbuild and the body 'matches' the chassis. The plan is Romfords plus Mainly Trains rods. And probably Romford deluxe crankpins. The slightly too high ride height will be cured with the Romfords. I may need to mill the chassis a little behind front and rear wheelsets to ensure it navigates 2' min radius with all flanged - unless anyone can tell me it will work anyway? My specific question is: I was planning to use TWO sets of MT rods, cut and rivet them to give one articulated set. Has anyone does this? Is it necessary? Or do the deluxe crankpins give enough sideplay? I'm curious as to whether articulated rods will improve or worsen running quality? Hence my question whether really needed... Thanks.

So, coming back to the Mainly Trains rods that have arrived: I see they are NOT articulated, but I deliberately bought two sets so that I could manufacture one articulated set - it would see not to be necessary, albeit of course preferable. (I've got various Markits rivets in stock...) Views?

One technique I have tried is to use a rolling pin and a towel placed on a kitchen top or similar. Once cut to pretty much the right size, warm the plasticard with a hair dryer, then roll gently until it assumes the right curvature. As an aside I've also used this technique (with a thick towel) to 'roll' car number plates to fit a very curved front panel!

Yes it's 13mm... And of course with the Romford axle we can't nip up the B2B. Having said that, nothing to stop me milling something off of the front and rear width. Centre would be easier but that's the driven one so ideally want to keep that with limited play.

For those interested, this is the K's 'Bodyline' kit for the 97xx on the prescribed HD chassis.

Yes all wrong I appreciate, but it was as John says K's choice...

Revisiting a very old thread I appreciate, but found it as about to post a Q about the HD R1 chassis which I have used on a K's 97xx bodykit. The 97xx has come out quite respectably and might warrant a better looking chassis without going fully bespoke. So, to those who have done this: (a) If I fit 20mm Romfords/Markits with all flanged, is there any issue with e.g. 2' radius curves? (b) Using the MainlyTrains rods, are they articulated or just dummy? Do they need to be articulated on this chassis if again running 2' radius? Thanks

yes that may well be the answer as many were buffer-less. I did remove the set end buffers and put a straight beam Plus correct pattern buffers on as per original, but left the less visible intra-set ones as standard.

Yes, I would have used a bar but eed to be able to box them at the moment. Might make up something along the lines of a doubel-ended fishtail NEM design which can clip in and out of the Airfix coupling slot.