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A P4 Hornby Ruston 48DS


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Recently I was offered, free, a body for the Hornby 48DS.  The owner had used the chassis for a 3D printed body of his own manufacture and had no further need for the Hornby body.  It was the 'whisky' one, in Brown, which I will in due course be repainting anyway.  I have been following and contributing to the Hornby 48DS thread and have decided that now I've actually started on the project I would start a new thread here.

 

The idea is to fit the Hornby body onto a High Level 21mm wheelbase Quad Driver which Chris has produced for powering the Judith Edge kit.  I am presuming (indeed hoping!!) that it will fit the Hornby body as well, especially as I have now ordered one along with a small motor.

 

When I received the body the owner had removed the 'side panels' already and I was relieved to find there was no damage to the bonnet sides.  Perusing the photos by Porcy Main posted on the Hornby thread, and following his 'instructions' I managed to dissassemble the body and break it down into its constituent parts ie, footplate, cab, cab roof, bonnet and buffer beams.  I hadn't realised that it was virtually all metal and initially was wary about cracking plastic parts but I needn't have worried.  Apart from some 'cracks' when areas of stuck paint were separated all was OK.

 

558769527_Ruston48DSParts.jpg.22ce0eeec05c1c764dd92c7a8e4f586d.jpg

 

The footplate was very easy to detach from the superstructure, just 2 small screws and these were stored away in a small ziplok bag.  The inside of the 'wheelarches' is to narrow to take P4 wheels and needs to be widened.  This has been done (so far one end only) with a selection of rotary cutters in my Faux Dremel plus the occasional use of a sharpened jewellers screwdriver to gouge out bigger chunks.  The casting is quite soft and even a sharp scalpel will remove some surplus metal.  After gouging, the rotary cutters were used to smooth over the surface.

 

1365887133_Ruston48DSWheelarchenlarging.jpg.8d5e4aca0dd8bca276f1754edbe7aaa1.jpg

 

While doing the 'dremelling' I rested the chassis on its side on a piece of 1/8th inch balsa wood.  The projecting steps and lifting eyes were able to sink into the soft surface and be protected from damage while pressure was applied to cut the excess metal away

 

648035517_Ruston48DSFootplatefilingbase.jpg.ee0f016ae1dda26a3348fc07e6b47630.jpg

 

I now need to cut away the other pair of arches and then my plan is to make a dummy set of inside frames to check I have the correct height and spacing to fit the High Level Quad Driver in the correct position.

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On 02/10/2021 at 09:15, Michael Edge said:

You will need some sort of frames to hold the axles, the High Level Quadriver only links the axles, it fits inside inner frames in our kit.

That's what the 'dummy' frames are for, to create a template to cut some metal ones.  The potential trouble is that the 'slot' in the footplate casting may be slightly narrower than the overall max. width of the Quadriver so some judicious filing may well be in order.  Until I build the QD I won't know for sure.  The whole project is beginning to appear more involved than I initially thought!

 

Still need to know what then threading is for the footplate/Hornby drive unit fixing screws.  Possibly 2 - 2.5mm?  8BA to big, 10BA to small.  I'm not sure what (if any) metric screws I have.

 

EDIT - just found Porcy Main's post in the Hornby thread!  He says 2mm coarse thread.

 

ANOTHER EDIT - forgot to say that I ordered the QD and another box and motor on Thursday and they dropped through the letterbox Saturday morning.  Great service from Chris.

Edited by 5050
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  • 3 weeks later...

Progress at the moment is rather slow I'm afraid due to a combination of circumstances and I'm only working on this roughly every third week.  However, I have made some progress as the following photos show.

 

The wheel arches have now been fully opened up to take the P4 wheels, using a combination of 'dremelling' and gouging using a well sharpened jewellers screwdriver.  The 'substrate' is a relatively new purchase, a honerycomb ceramic soldering 'mat' which I find very useful, both for soldering and for holding small items whilst filing etc.

 

490023752_Ruston48DSFootplateFiled.1.A.jpg.555dc1e432ed71295a62c242b23a85cb.jpg

 

Next view shows the tools involved in the work along with the HL 'Rustler'  Quadriver assembled.  i have to admit that putting this together was one of the most problematic of all the HL gearboxes I've built.  Some of this was due to my apparent ineptitude but also the rather tricky assembly sequence necessary to get everything in the right place.  It has turned out to be slightly to wide to readily fit into the footplate slot but a bit of strategic grinding/filing will sort this out.

 

1545509018_Ruston48DSFootplateFiled.2.A..jpg.5791d8c7bb4b9203d092307d486a94a7.jpg

 

To complete the assembly there is a need to solder nickel silver parts to the silver steel axle in a couple of critical places and I had difficulty in getting the solder to 'take'.  To use to much heat may have affected the plastic gears so these were left out where possible until soldering was completed which I eventually managed - but I'm still not sure if the joints are fully satisfactory hence the use of nail varnish as well.

 

The AG wheels are removed from the pin-point axles which are then turned down to length and the wheels refitted.  The non-driven end can be assembled as in the photo but the driven end will have to have wheels fitted  through the gearbox etc. when the time is right.

 

Now to make the frames!

 

 

 

 

Edited by 5050
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On 19/10/2021 at 15:44, 5050 said:

...

 

To complete the assembly there is a need to solder nickel silver parts to the silver steel axle in a couple of critical places and I had difficulty in getting the solder to 'take'.  To use to much heat may have affected the plastic gears so these were left out where possible until soldering was completed which I eventually managed 

...

A couple of years ago I had this problem. I replaced the silver steel rod with 2mm o/d brass tube. I found this tube was every bit as accurate as the steel rod but it's easier to work with. I also replaced the soldering with just squeezing the ends of the axles with side cutters. This not only cuts the tube but distorts it so keeping the axle in place.

The results are not pretty, and it may only be suitable for use with P4 width frames, but if you need to solder it will be a lot easier. I seem to have archived the photos I took, I'll try to find them.

 

Edited by PenrithBeacon
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19 hours ago, decauville1126 said:

RT Models do a set of etched frames already for a 48DS, conceived I would think before the High Level Quadriver was developed to suit Mike Edge's superb etched kit. Might need wheelbases checking though. I wonder if that might help?

 

Scroll down to find it on

https://www.rtmodels.co.uk/rt_models_032.htm

 

 

Only 2 wheel drive (not necessarily a bad thing but 4 wheel is better) compared to the Quadriver which wouldn't fit due to the central 'spine' and spacers.  Making my own chassis has been more 'interesting' than I initially envisaged.  There's a lot of conflicting elements in the fabrication and allowances/clearances have to be made.  There may also be the need to make alterations to the' body' of the Quadriver to make sure I can fit it between spacers etc. - and I've also got to work out how to best fit pickups.

 

Keeps me occupied:rolleyes:

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  • 2 weeks later...

The saga continues, read on.  Progress is rather sporadic due to life getting in the way but I have made some.  Mainly in connection with the chassis and it's interaction with the footplate casting.

 

Here's the various parts prior to assembly.  The assorted spacers are all 'spares' from previous kit builds.  The chassis sides require unsoldering after final cutting to shape.

 

1537914816_Ruston48DSchassiselelments.jpg.3ccdd5987d3e3eb98ec8b9e94fcaebac.jpg

 

The sides separated and 2mm studding, washers and nuts used to space them apart for the spacers.  My usual heavy brass 'assembly jigs' can't be used as they are for 1/8" axles and much to big for the size of this chassis.

 

2038736618_Ruston48DSchassisparts.jpg.939a98367dafc36b01b7f5d2b0dcb5b9.jpg

 

Sides assembled together with spacers selected from the assortment in sizes that would hopefully not interfere with the fit of the gearbox.  I had to trim some material away after checking with the fit of the gearbox.  Note that I have soldered some spacing pieces on the outside of the sides to minimise side play which will assist in keeping the final drive gears meshed with the others.  I had to have a couple of attempts at soldering all this up as the first came out a sort of banana shape for some reason!  Note that the top of the sides is not totally flat as the underside of the footplate casting is in 2 levels.

 

1427088376_Ruston48DSchassisassembledtopside.jpg.1be9f4c21ef3204028a25ffa121394a2.jpg

2100287367_Ruston48DSchassisassembled.jpg.0944b33ba6d8f4c51d4af06f76702899.jpg

 

To provide good clearance for the sides and various protruberances on the Quadriver I filed the insides of the footplate.  As the casting is quite soft this is not difficult.

 

1847617347_Ruston48DSfootplateinnersidesfiled.jpg.e7c82ef8c32d7f649d967926c9d7300c.jpg

 

Now for one of those " 3 steps forward, 2 steps back" moments.  Or rather 3 forward, 4 back!  Up to this point I had been working on the premise that the motor/gearbox would be at the cab end (don't ask me why 'cos I don't really know!).  I then realised that it would fit quite happily into the bonnet and leave the cab totally free.  However (as usual!) there was a problem.  The wheels are not equidistant from each end, the front pair are 1mm further away from the end than the rear.  This meant that I could not just reverse the chassis as the wheels would not line up with the outside bearing castings so I had to saw 1mm away from the front end and make up the difference at each end with some 40thou and 20 thou plasticard packing so it fitted snugly.  I also decided to attach a piece of 1/16" brass into the footplate casting (Araldite) drilled and tapped 8BA for a screw fixing through the larger spacer.  I think this will be quite adequate to hold the chassis in place on its own with no need for a fixing at both ends.

 

577659038_Ruston48DSChassisFixingplate.jpg.5a42a449f7d518ca0c4fc35afed19787.jpg

877731721_Ruston48DSChassisinFootplate.jpg.1ad9df2b2e0bccbc2b5ac930106d14c1.jpg

 

The wheels on suitable shortened axles (21.8mm if you need to know) just clear the inner face of the wheel arches but, to date, I haven't checked with a meter to see if they might short out.  Some more grinding/chiselling might be on the cards. Side play is minimal but with such a short wheelbase it shouldn't be a problem and, in some ways, actually be better.

 

I've also been working on final assembly of the Quadriver (and dissasembly as well!) and photos will appear in due course.

Edited by 5050
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Due course has now arrived - and a lot quicker than anticipated.  Here's some shots of the almost completed Quadriver and its relationship with the footplate casting.

 

The Quadriver in its (hopefully!) final state with only the trailing compensated axle to fit wheels to.  I was having problems with the 'swivelling' of the geared arm.  It didn't seem to want to provide much movement for the compensated axle and i was concerned that running may not be to good.  I decided to partly dissasemble it by removing the 'axle' on which it fits and refabricating it.  As it happens, the soldered NS/Steel joint between the arm and the axle had failed anyway (see above posts regarding this) so I took a leaf from Penrith Beacon's book and substituted it with a length of 2mm brass tubing.  When I removed the redundant steel axle I discovered that it was corroded along its length due to the ingress of the acid flux I had used.  The gear wheel had hidden this up to that point.  The new brass shaft was secured with (easily) soldered 2mm washers at either end using a thin paper 'spacer' at one end to allow a modicum (ie - sufficient) of movement.

 

68933405_Ruston48DSQuadriverassembled.1.jpg.9af533bcca827e9eb316674dd3b832e8.jpg

 

Here it is with the footplate showing the 1mm NS wire beam.  I had intended using a steel wire for this but again, I could not get it to solder to the brass frame spacer despite using a variety of fluxes.  The NS wire went straight on and will be adjusted for height once all wheels are fitted.

 

1621378827_Ruston48DsQuadriverassembled.2.jpg.da064e823a8f3c2e9939762dde56e8b6.jpg

 

The Quadriver is a snug fit into the footplate casting.  It is just narrow enough to fit inside the bonnet and the location slots for the bonnet can be seen close to the gearbox.

 

718409763_Ruston48DsQuadriverandfootplate.2.jpg.20971985b0ebafe808b6a77773e3037a.jpg

1533977813_Ruston48DSQuadriverandfootplate.jpg.fe7be36d8453b213ee911919b2372fd3.jpg

 

I had a bit of a game fitting the final drive gear to the driven axle.  Chris states in his instructions that, due to potential variations in axle diameters, the press fit may be tight. I found it very tight!  I had to take a 2mm reamer to the axle hole and seemed to remove more material than I was anticipating - and it was still a tight fit.  The other gear wheel may end up being reamed even more drastically.

Edited by 5050
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1 hour ago, 5050 said:

...

I had a bit of a game fitting the final drive gear to the driven axle.  Chris states in his instructions that, due to potential variations in axle diameters, the press fit may be tight. I found it very tight!  I had to take a 2mm reamer to the axle hole and seemed to remove more material than I was anticipating - and it was still a tight fit.  The other gear wheel may end up being reamed even more drastically.

I found that the swivelling arm had quite enough movement in yaw to enable compensation, although, as the proof of a pudding etc, the model still lies uncompleted.

It, an RT Sentinel, needs a scratch built  chassis for P4 and I made a mess of it first time around. Must get back to it but the mojo has gone.

After reaming out the drive spur gears, I found it was necessary to drill and tap 1mm for grub screws to be sure of fixing to the axles. Said grub crews ar available on eBay with either a socket or slot for allen keys or screwdriver

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1 hour ago, PenrithBeacon said:

I found that the swivelling arm had quite enough movement in yaw to enable compensation, although, as the proof of a pudding etc, the model still lies uncompleted.

It, an RT Sentinel, needs a scratch built  chassis for P4 and I made a mess of it first time around. Must get back to it but the mojo has gone.

After reaming out the drive spur gears, I found it was necessary to drill and tap 1mm for grub screws to be sure of fixing to the axles. Said grub crews ar available on eBay with either a socket or slot for allen keys or screwdriver

I can supply the chassis if you still want one? Just need to know which one as the post war chassis is unique to all the others in the series.

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Paul, this is very interesting indeed. It looks very good so far and there are echoes here of my building a very similar chassis (albeit in OO) for the Roxey Planet, featuring one of Chris's similar 4-wheel drive gearboxes.

 

I'm interested in the AG wheels you've used. I've got some 10.5mm Black Beetle wheels waiting to fit to a Hornby 48DS. I can see now that I will also have to get the Dremel out, but were your AG wheels 10.5mm or smaller, please?

 

Thanks.

 

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2 hours ago, RThompson said:

I can supply the chassis if you still want one? Just need to know which one as the post war chassis is unique to all the others in the series.

The problem here is due to rendering the the prototype in P4 or 18.83.

The wheelbase of the prototype is 4'-9" (19mm) on a track of 4'-8.5" (18.83mm) leaving the P4 modeller with just 0.5" (0.17mm) to play with. It's fine in 00 because 16.5mm is playing 19mm, but I don't have the skills to work with just 0.17 mm.

I decided  to extend the wheelbase of the model to 20mm (5'-0") which would give me 1.17mm to work with a scratch built chassis. I got the wheelbase correct ok but got the side profile of the frames wrong. Pig's ear.

I need to go again but not now,  but thanks a lot for the offer, much appreciated. 

:D

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That will be for the post war sentinel then as there was room for the motor to be up in the air hence the as designed and as built 4'9" wheelbase at 19mm.

 

All the other kits actually use 20mm wheelbase because the bonnets was low for the motor to stick up plus on the real locos the wheel bases was variable anyway to take the slack out the chain drives, up to 6 inches I think.

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10 hours ago, PenrithBeacon said:

The problem here is due to rendering the the prototype in P4 or 18.83.

The wheelbase of the prototype is 4'-9" (19mm) on a track of 4'-8.5" (18.83mm) leaving the P4 modeller with just 0.5" (0.17mm) to play with. It's fine in 00 because 16.5mm is playing 19mm, but I don't have the skills to work with just 0.17 mm.

I decided  to extend the wheelbase of the model to 20mm (5'-0") which would give me 1.17mm to work with a scratch built chassis. I got the wheelbase correct ok but got the side profile of the frames wrong. Pig's ear.

I need to go again but not now,  but thanks a lot for the offer, much appreciated. 

:D

I know you've said this before in another thread, but what is the problem having the wheelbase less than the gauge? It can't be the only example from railway history, and I really don't think anything terrible is going to happen. Of course any very short wheelbase vehicle is likely to waddle a little but then I'm sure this is true of the real thing, and P4 will be better at avoiding this than any other gauge I would think? Just interested...

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2 hours ago, Barclay said:

I know you've said this before in another thread, but what is the problem having the wheelbase less than the gauge? It can't be the only example from railway history, and I really don't think anything terrible is going to happen. Of course any very short wheelbase vehicle is likely to waddle a little but then I'm sure this is true of the real thing, and P4 will be better at avoiding this than any other gauge I would think? Just interested...

I'm surprised that it isn't obvious that the wheelbase has to be greater than the track gauge. I'm sure that it can be shown that this is true but I don't have the references to hand. I dare say that some RMwebber does have though.

IIRC the GWR had a broad gauge horse box that had a wheelbase of 6'-6" and that vehicle always had to be marshalled with other vehicle behind and in front because it was wildly unstable otherwise. 

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47 minutes ago, PenrithBeacon said:

I'm surprised that it isn't obvious that the wheelbase has to be greater than the track gauge. I'm sure that it can be shown that this is true but I don't have the references to hand. I dare say that some RMwebber does have though.

IIRC the GWR had a broad gauge horse box that had a wheelbase of 6'-6" and that vehicle always had to be marshalled with other vehicle behind and in front because it was wildly unstable otherwise. 

I do see that that stability is worse the shorter the wheelbase. However you are making a model of something that existed in the real world, and which works well enough. In fact the 48DS was available in gauges up to 5'6" with the same wheelbase. Even in standard gauge it is very nearly 'square' of course but as long as your model is close enough to the real thing in terms of scaled dimensions then I can't see why it wouldn't work - fractions of a mm above or below 18.83mm can't possibly make any significant difference. Having said that the drawings I have show the Wheelbase of the 48DS to be 5' 3 3/4" which is just over 21mm. This should give enough leeway?

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One of the reasons I have only allowed a very minimal sideplay in the wheels is to try and avoid 'waddle' and 'crabbing'.  With the short wheelbase and the wheel/rail tolerances inherent in P4 there should be sufficient 'slop' (!) for the loco to get round tight curves.

17 hours ago, Captain Kernow said:

Paul, this is very interesting indeed. It looks very good so far and there are echoes here of my building a very similar chassis (albeit in OO) for the Roxey Planet, featuring one of Chris's similar 4-wheel drive gearboxes.

 

I'm interested in the AG wheels you've used. I've got some 10.5mm Black Beetle wheels waiting to fit to a Hornby 48DS. I can see now that I will also have to get the Dremel out, but were your AG wheels 10.5mm or smaller, please?

 

Thanks.

 

Wheels are 2-hole discs a nominal 11mm diam over thread.  I have drilled through the moulded 'hole depressions' at 0.8mm and added an extra 2 holes at 90' to make them 4 hole.

 

BTW, I built a Roxey Planet as well a while back using the 'under-the-counter' unit that Chris designed for Gordon Ashton.  I also used one of them adapted for use in a Branchlines Sentinel.  After this I now have no qualms about attacking one of Chris's products to make it fit!

Edited by 5050
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1 hour ago, PenrithBeacon said:

I'm not talking about  the 48DS but the post war Sentinel. 

My apologies, but I still think a slow moving shunting engine would work just fine with a WB less than or equal to the gauge, and would like to see it built.

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I have a 48DS in P4, which I bought ready-built from the Impetus kit from a friend at the club a few years back. It runs quite nicely, but now I'm going to have to go and check the wheelbase!

 

blogentry-57-0-89965800-1393886125.jpg.19fa458eacf213db98c3ed10a9d2e12a.jpg

 

Edited by Captain Kernow
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8 hours ago, PenrithBeacon said:

I'm surprised that it isn't obvious that the wheelbase has to be greater than the track gauge. I'm sure that it can be shown that this is true but I don't have the references to hand. I dare say that some RMwebber does have though.

IIRC the GWR had a broad gauge horse box that had a wheelbase of 6'-6" and that vehicle always had to be marshalled with other vehicle behind and in front because it was wildly unstable otherwise. 

You brought this up on a thread in the Industrial section and it's not obvious to me. I didn't get it then and I still don't get it now. There are many prototypes with a wheelbase that is barely the same dimension as the gauge. The Sentinel at 4ft.9in, Manning Wardle 0-4-0STs with the same wheelbase and dozens and dozens of Wickham trolleys, some of which had a wheelbase far less than their gauge dimension. It clearly worked on the prototype, so what is it you think will happen to a model if it has a wheelbase as short as the gauge dimension?

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