Underneath her skirts - a LIMBY Skinhead shows off...
Entry posted by EHertsGER
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As an adjunct to my post on the subject of Brush Type 2/Class 31s I thought I would add some notes on how I 'butchered' the LIMA chassis to support the Hornby motor and bogies etc so here we go...
First off the LIMA chassis has to be stripped of all its gubbins - though keep it; I have heard that a 'double-motored' LIMA 31 is a beast to behold - I may yet try one! So too, the Hornby, which has probably shed a few bits along the way. Some those little 'baggies' come in handy making sure things don't get muddled/lost here.
Onwards. I have presumed at this stage that there is a Hornby donor available. I have yet to try this without the buffer beam shrouds from a donor as they are unavailable as spares. Anyway, the LIMA buffer beams are all wrong - anemic shroud on the outside and a curved buffer beam within, so just lop it off level with the underside of the chassis. We will come back to this later.
Next to go is the fuel tank. at this point replace it with the one from your donor Hornby - make sure you get it the right way round to match the original. The gauges and inset part are at the number 2 end (the one without the fan).
Now to some fabricating. You will need some black (saves painting it later) plasticard in 0.040", 0.060" and 0.080" thicknesses. Some 0.020" may come in handy too. You will also need a sheet of 1/8" thick lead and some liquid gravity stuff, epoxy and superglue.
Tea at this point works well...
Off we go. Cut a piece of lead 80mm x 20mm and set aside. Now the solvent has set on your replacement fuel tank stuff as much lead as you can into it until it comes up to the level of the chassis moulding floor. Any gaps can be stuffed with liquid lead to get the most weight into it. Note that your heaviest option here is always going to be lead. Next comes chilled #12 shot (chilled as it has a higher density/animony content (or is that less antimony?)), regular #12 shot (see your gunsmith/tackle shop for this, probably) THEN Liquid Gravity - good stuff though it is, it is not lead and it is not 'packable' as it is a lot of tiny spheres (as is shot), each of which will have air around it however cozy they may get in confined spaces. Result? So far I have noted that lead will weigh twice as much as liquid gravity when packed into the same space. So, lead sheet it is. Tip some cheap superglue in and stand well back - and I mean well back. The fumes are not nice.
By way of comparison my LIMA 'core' chassis (not motor etc) weighs in at 250g against the Hornby chassis minus the cab ends/buffer beams that fell off that weighs in at 215g.
While the fumes are dissipating cut some 0.080" into 20mm wide strips long enough to be half the remaining length of the chassis less the 80mm of lead you just cut.
Once your chassis is nicely set it should already have some heft to it. Now cut those 0.080" 20mm wide strips to fit inside the outer rim at the 'nose' of each end with the 80mm x 20mm lead sheet sitting over the fuel tank - you can stick that down centrally too if you like. I left it until I got all the bits to fit. Then, bond the shaped 'nose' sections to the floor of the LIMA chassis moulding. The chassis suddenly becomes surprisingly strong and rigid at this point.
Now for the stressful part. What you are trying to achieve is to replicate the shapes and bogie mounting hole you have in the Hornby chassis, so cut with care measuring and checking all the time. Sorry I can't give any measurements as it is all now assembled...but I am sure you get the idea.
At the #1 end (the one with the fan) cut and mount a piece of black 0.080" plasticard across the chassis to give the bogie a rubbing plate - see the left hand end in the picture of the underside of my chassis, below. Don't worry about drilling it out again yet, just get it mounted and set, the redrill your hole for the bogie pivot to ensure a clean hole all the way through. A pillar drill comes in handy here. At the #2 end do the same with 0.060" plasticard. These thicknesses suited the height of the loco I had - but check your heights etc to make sure it sits right before securing these pieces. Once they are secured, drill a couple of holes to allow the power leads to access the upper body work (see them just behind my bogie mountings?)
At this point you should be able to set the body on the bogies and feel happy it is sitting right. Keep on checking!
Going back to the upper part of the chassis, cut and fit another piece of 1/8" lead to fit into each of the 'nose' sections but clear of the arc of the bogie pivot hole. Over that add a piece of black plasticard to bring everything level with the outer rim of the chassis (see photos). This will form the cab support in the future.
In the center, over the lead sheet add a piece of black plasticard (I used 0.060" I think) cut to clear the motor and universal joint links, but making sure a snug fit to the outer rim and bond it in place against the rim with solvent. You can ooze some superglue underneath too, if you like. Depends if you like the fumes...
On top of this motor frame you can build a frame on which to seat the circuit board, best understood from the pictures below...
That's about it for the chassis apart from assembly.
It all goes together the same way the Hornby one does apart from the bogies. The clips that go over the worm gear housing will need the half round pivot points reduced to ensure they are a secure seat on the bogie - the floor is now a lot thicker here than the Hornby chassis. I am sure it can be done without the need for this using a thinner floor, but I chose to add a strong full length brace above, so ended up with a thicker floor etc.
I hope the following photos help...
Now, the buffer beams. Taking stuff from the Hornby donor you will have two buffer beam shrouds but probably no buffer beams as these are cast and most likely have fallen to bits...
So, out with the 0.080" black plasticard to fabricate both a new beam and the reinforcing section - the 'flat' bit parallel to the track - you can see in the photos above. Bond all that lot together with solvent and you have a buffer beam unit that can be screwed to the chassis (into all that nice thick plasticard and lead you have above the floor, remember?) or simply bonded to the chassis with solvent. I chose the latter. After that, decorate as required (pipes, couplings, buffers and so on as listed in my previous post).
I hope that is a useful set of pointers to convert the chassis. Wiring it all up again is the same as the Hornby one (you did make a note of which wire goes where on the circuit board, didn't you?) No?
Better? Now for the paint shop...
Best,
Marcus
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