Priory Road - North East Essex in BR days

[Izzy]

10 hours ago, Nigelcliffe said:

A few thoughts and observations on the 05.   

When I built my 02, I used a solid square brass bar in the chassis between the frames to put the weight low down. 
Slotted to clear axles (so drop-out wheels can work), and I used a milling machine to cut clearances for gears, but a simpler solution with saw/file would also work. Or can build the solid brass up in four layers of 1/16th brass, fretting each to shape to clear gears/muffs in each layer. 
The solid brass needs insulating from the frames, which is either the old-stand-by of thin paper, or I did it by using thin PCB for the frames with bearing bushes for each axle.   PCB meant that the frame was only electrically "live" in the area near the wheels, it was gapped at the ends where the frame screws went into the spacer (hidden behind the body steps).   

 

Flycranks.  In 4mm and 2mm I'm now copying Farish's approach on the 03/04.  The crank is not on a through-axle connecting each side (no quartering), and the crank bearing is very very sloppy (one of my recent 4mm locos is something like a 2.8mm axle in a 3.2mm hole).   Some of my locos have used half-axles on the crank, with a free running tube to keep the axles "in line" with each other, but allowing the independent movement.    The crankpin to coupling rod is sensibly sized for running and low slop.   With rigid rods, this works fine, the rod will lift and push the crank around as required.  

 

Another alternative for flycranks is to copy the High Level kits "Illusodrive".   Gear the crank shaft from the driven axle with spur gears and don't fit any crankpins between rods and crank (crank pin washers/nuts are good to add to the illusion).   The crank is therefore gear driven, and the rods just waggle around in fresh air next to them.  

 

 

- Nigel

 

1 hour ago, Nigelcliffe said:

 

The standard throw is 2mm for wheels from 8.5mm dia upwards, the smaller wheels are reduced.  7.5 and 8mm wheels are 1.75mm.   The 7.0mm wheel is 1.5mm.   (Custom sizes/throws are possible, as are custom spokes/balance weights, etc.. they'd be special orders.  ).  

 

- Nigel

 

Thanks for all the info on chassis construction, as always very helpful insights on how to approach things. Gives me plenty to consider. Much appreciated. The idea of split flycranks a la Farish would allow room for chassis to body and keeper plate bolts. Also the crank throw. There appears to be a set of flycrank etches at 1.5mm so that's helpful.

 

As said earlier I've just recently made a couple of replacement rod sets for my Farish 03 & 04. These were 'cut & shut' from other association 2-layer etches and I just put a pin in the flycrank ends to just sit in the hole. The Farish pin is a tight push fit. Works just as well - thankfully.

 

Here's a few shots which should help explain, I hope. It needed two sets, a 4 coupled and a 6 coupled to get the 8 coupled equiv with the flycranks.

 

 

 

 

 

 

 

A before /after comparison

 

 

Not as good perhaps as the blue 04 with the etched association chasssis, but acceptable, and run just as well.

 

 

Bob

Edited September 19, 2022 by Izzy

[Nigelcliffe]

Just to add on the topic of fly cranks.   I have an Farish 04, which I converted to 2mm wheels over a dozen years ago.  It's the one I used to develop the DCC-controlled couplings.   
For some good reason (possibly the screws were steel and attracting the magnet in the coupling mechanism), I removed the fly cranks on that, and left the end of the rods waggling in fresh air under the steps.   Absolutely nobody has commented up it, including those who've studied the movement of the uncoupler at very close quarters.   It has been on layouts and test tracks at numerous shows over the years.   

 

 

- Nigel

[bradfordbuffer]

12 hours ago, Nigelcliffe said:

Just to add on the topic of fly cranks.   I have an Farish 04, which I converted to 2mm wheels over a dozen years ago.  It's the one I used to develop the DCC-controlled couplings.   
For some good reason (possibly the screws were steel and attracting the magnet in the coupling mechanism), I removed the fly cranks on that, and left the end of the rods waggling in fresh air under the steps.   Absolutely nobody has commented up it, including those who've studied the movement of the uncoupler at very close quarters.   It has been on layouts and test tracks at numerous shows over the years.   

 

 

- Nigel

Deception is the art of not telling any one of your intentions! Rivet counters will now ask where your flycranks are! Triang never bothered with center wheels on class 31s.....

[Izzy]

An Engineering Train

 

Although producing the running sequences for Priory Road has been very helpful in working out what stock to use, it’s also meant that some items then never get used unless I adjust things to suit. This I like to do to ring the changes and one such item is the engineering train I have assembled.

 

 

As with some other aspects this came about in a piecemeal way, individual items I made that took my fancy, a Farish blue 04 I acquired and re-built with an etched chassis and other improvements

 

 

a Cowan-Sheldon 6T hand crane I made along with a lowfit as a runner,

 

 

a Toad E brake van etched kit.

 

 

All separately done because I just like making things before the notion arose that perhaps I could arrange them into a train to run together. This then expanded a bit to include three grampus wagon kits that came my way along with a bogie bolster.

 

The 30t bogie bolster belongs to the ST department and has some signal posts on it, ones just taken down having been replaced by colour lights.

 

 

The crane was used to help remove and replace them. One grampus has some track timbers and chairs, another new ballast, while one is there empty to carry away surplus stuff that has been removed, spoil/old ballast/timbers etc.

 

 

I think possibly there should be a brake at both ends, and perhaps a mess/tool carriage as well. I can of course keep adding…..

 

This train helps show I think that mixing 1:148 & 1:152 often looks quite okay together depending on what is used. The bogie bolster is Farish like the loco so both are 1:148 while all the rest are 1:152. Just changing the couplings and wheels on N gauge stock alone makes a considerable difference, especially with the latest Farish correctly scaled stock.

 

As the present sequences have places where extra trains can be slotted in that is what I tend to do. Running this engineers one with using all the stock mentioned provides another excuse for some shunting because it is too long for the loop. Without a second loco to assist it means the train loco has to perform running around it in two halves.

 

 

The loco pushes it all back up the line, brings half forward and runs round it

 

 

collecting the rest before placing the first half in the parcels platform

 

 

 

and then running round the rest.

 

 

The final job is shunting the brake into the main platform road via the release crossover so it ends up at the rear again.

 

 

 

And it's ready to go off.

 

 

I can of course run what I like when I like. Play with anything. But using running sequences brings some purpose to it to my mind, so now I’m getting them organised I prefer to use them, and mixing an ‘as required’ train into it adds to it.

 

Bob

[Izzy]

A Hunslet 05 in 2mm – pt 2

 

While I consider all the various options for the construction of the chassis I’ve continued investigation of the body parts on the etch to see how it all goes together. Removing them from the fret with a very sharp (new) curved scalpel blade so I could cut the half etch tabs as close to the items as possible and leaving the minimum amount that requires cleaning up with a fine file. It’s very high quality etching and some parts such as the radiator grills and window frames etc. need the utmost care given how fine they are and so easily distorted.

 

 

The design uses half-etched holes on the rear of parts which are pressed through with a sharpish point to produce rivet detail on the front. I like this method because it means the etch retains more inherent strength. I used an old compass point needle held in my hand drill.

 

 

 

With brass etch you have to be careful not to press too hard because it’s all to easy to make a hole. With nickel-silver being harder this is not such an issue, indeed sometimes firm pressure is required to produce a decent result. Using a hammer to give a light tap though, often used in larger scales, would be a mistake. I didn’t try it even on a scrap piece. An instant hole I would think. They are fine and look nice in the raw metal. I do wonder if some will disappear under a coat of primer and top coat but this is the danger in this scale with much fine detail and there is not much you can do about it.

 

 

Just to give an idea of the size of the bits for anyone not used to the scale here's the front with a pin.

 

 

With both the cab & the engine casing the sides have half etched rebates into which the back/fronts fit. There are half etch lines for the folds on the inside of the casing and rebates into which the doors fit on the outside.

 

 

Since the latter makes folding the lower section properly more difficult as it has less strength I did consider fitting the doors in place first, on the flat. I didn’t in the end, on either, but if I were to make another I think I might. I’ll come back to this aspect in a minute.

 

Although the recommendation is to form the rivets after bending the casing to shape, in 2mm I couldn’t see how this could be done, no room to get to the inside. So I did these first.

 

 

As there were two casing etches I thought I would practice on the larger one first, forming it to shape, before tackling the smaller one I would use. Large and small is a relative term. The height difference is about 0.5mm so you have to be careful about getting the right set of parts together. They have etched numbers on them but I have been known to muddle things up in the past……

 

The top of the casing is curved. This I first bent gently to shape using finger and thumb pressure. Practising on the first casing proved useful as I didn’t seem to get it quite right. I don’t know how but it seemed to crease in the middle a bit. Thankfully the other went okay.

 

Initially I intended to form the bends with my simple fold/hold tool I made. This worked okay on the top bend, but not on the lower one.

 

 

 

The metal wanted to bend at the weakest point, as you might expect, which was where the half etched rebates for the doors start. I had to use snipe nosed pliers to straighten things and think again. This is why I think I would fit the doors first, soldering them in to give the strength required. It might help, might not, no telling. So I then tried using my small hand vice. But first I scored the half etched lines a few times with a scalpel to try and help. Carefully and not too hard so I didn’t cut right through or cause the etch to fracture here. I have had both happen in the past and then you really have your work cut out sorting it. Cutting through more likely with brass, fracturing with N/S. Gripping the etch tightly at the top of the bend worked, although because the vice is only small it needed doing in two halves.

 

 

 

 

With the second casing I used instead the snipe nosed pliers. Again needing two goes, from the front and back edges, and gripping very tightly, but it again did the job. Phew.

 

 

The front of the casing with the radiator is curved. Again this was formed with finger/thumb pressure.

 

 

 

At this juncture I should mention that the design is again a bit different in that the cab and engine casing are soldered to a sub-base then attached to the footplate as a unit. A neat idea so long as it’s all kept flat and square. Shows the thought that gone into the design. Oh, I should just add that you will see holes around some edges. These are registration holes, so parts can be lined up using them. Another nice idea. An alternative to half etch or tab location where it suits the design. 

 

 

 

This is now where I’m up to. The next step is to try and sort out the basic chassis design before going any further because I’m sure the footplate and sub-base will need some alteration whatever chassis construction I go with, and need doing so before anything is soldered to them.

 

I often see and read accounts of construction where the body and chassis are built entirely separately, one first and then the other, with often little thought of how they will fit together and then needing subsequent ‘adaption’ to get there, risking damage to the already assembled parts.

 

Maybe it’s because the first loco I ever built was done from scratch, when I was in my late teens, but whether it’s been a kit or scratch I’ve always done things together in stages to be able to work out where it all fits as I’ve gone along. And some kits I’ve encountered in the past haven’t, even though of course they were supposed to….. I would guess many of us have been there.

 

Bob

[Caley Jim]

5 hours ago, Izzy said:

I often see and read accounts of construction where the body and chassis are built entirely separately, one first and then the other, with often little thought of how they will fit together and then needing subsequent ‘adaption’ to get there, risking damage to the already assembled parts.

I always build the chassis first and get that running before starting on the body.  I can then check at each stage of the body construction that a) the chassis will fit and b) there are no short circuits.  If you build the body first, then try to fit the chassis into it and it won't fit right home, how do you find out where you need to make adjustments?  Also if you find that there is a short when you put the completed body and chassis together, how to you diagnose what is causing it, other than by (lengthy) trial and error?

 

Of course I draw the whole thing up in CAD first so I know how it all should fit together.

 

Jim

[Izzy]

12 hours ago, Caley Jim said:

I always build the chassis first and get that running before starting on the body.  I can then check at each stage of the body construction that a) the chassis will fit and b) there are no short circuits.  If you build the body first, then try to fit the chassis into it and it won't fit right home, how do you find out where you need to make adjustments?  Also if you find that there is a short when you put the completed body and chassis together, how to you diagnose what is causing it, other than by (lengthy) trial and error?

 

Of course I draw the whole thing up in CAD first so I know how it all should fit together.

 

Jim

Yes, I too like to get the basic chassis up and running first, but do you make the footplate/ tender base etc just to check attachment points as you go, or leave it all until later? As I tend to scratch build as much as I use etched kits and of course you cut each piece to fit as you go, I do it the former way. It’s interesting to learn the different ways people tackle things. 
 

Bob

[Caley Jim]

46 minutes ago, Izzy said:

Yes, I too like to get the basic chassis up and running first, but do you make the footplate/ tender base etc just to check attachment points as you go, or leave it all until later? 

As I said, I prepare a scale drawing (elevations and plan) before I start construction, at the same time thinking out how I'm going to assemble it. I did that with pencil and paper before I had CAD, having done engineering drawing at school. That way I can work out how and where everything is going to go together. I have to say that the design I end up with can sometimes be quite different to my initial thoughts. 

 

Jim

[bécasse]

43 minutes ago, Caley Jim said:

As I said, I prepare a scale drawing (elevations and plan) before I start construction, at the same time thinking out how I'm going to assemble it. I did that with pencil and paper before I had CAD, having done engineering drawing at school. That way I can work out how and where everything is going to go together. I have to say that the design I end up with can sometimes be quite different to my initial thoughts. 

I often do the same, especially if I have any misgivings about the method of construction. However I don't draw it out at the same scale as the model but at five times the size on 5mm squared A4 paper so that each square on the paper represents a one millimetre square on the model. Using pencil this is a surprisingly easy task but provides considerable salutary information on the construction of the model, in particular a reminder to take the thickness of the metal properly into account. The one warning I would sound about the technique is to be very careful where thin strips are concerned, the five times magnification of the drawing can suggest possible designs/modifications that the strength of the metal won't support in reality.

[Izzy]

It’s wierd really. Back in the mists of time, in pre-digital days, as a Technical photographer I used to do etching for a living, knocking out etching tools and so forth by the bucketload on a daily basis. Although I had all the facilities at my disposal, art studio, darkroom complex, etching plant etc, I never had the time to do anything for myself. Of course all artwork was produced at many times full finished size in the manner @bécasse describes and then reduced down using a copy camera to the finished size. The one I had, located in one of my darkrooms, was like a SLR/view camera upended onto it’s lens. It had 100w arc lights for illumination and was the size of a small car. The litho negatives produced could be from an inch up to 16”x20”.  I’ve never tried to learn CAD to do etching since. Funny old world sometimes isn’t it.

 

Bob

[Caley Jim]

Like @bécasse I used to draw it out on paper larger than actual size.  CAD lets you draw it to scale, but you can blow it up on the screen to check clearances etc.  As he says, though, you have to be mindful of the fact that it is several times actual size!  (Now how would I know that?)   I once printed an etch part out actual size to check that the folding would work and was slightly shocked at how small it was!  I had to print it out 2x size to actually fold the paper.  The etch worked fine as the fold lines and hinges made it easier to bend the metal than paper.

 

Jim

[Izzy]

 

A Hunslet 05 in 2mm – pt 3

 

Now I have some of the new 7mm mk5 wheels and a 7 x16 motor I’ve been able to do a bit more sorting out of the basic chassis arrangement. It might be a good idea if I mention at this stage that I don’t use a gearbox of any description. If I were to build a tender loco with the motor in the tender driving the loco wheels then that would be a basic requirement which the nice new gearbox from the 2mm association would fill perfectly. The problem I find with trying to use a gearbox in a tank loco or diesel shunter such as this is having to fit the motor onto the gearbox while the latter is in the frames, which also precludes the use of drop-in wheel sets. So I just have the worm gear mounted on the motor sitting in a mount of some kind to enable meshing with the worm wheel. Here is a shot of my N7/3 and one of the 08’s to show what I mean.

 

 

 

And while I'm about it one showing the basic strip keeper plate I use.

 

 

Mounts are made up using plasticard to get the right seating for best possible meshing, a bit of trial and error adjustment. A box type enclosure of some description made around the motor to keep it firmly in place once the meshing is correct. This also has the advantage that there’s no load placed on the motor by the friction involved in the shaft running in bearings in a gearbox or misalignment of it. With this design in mind I thought through the various chassis options I had, the suggestions that others have kindly made.

 

Use the etched chassis sides, which gave the advantage that the basic axle measurements were done. But meant a quite light chassis would result. I used 1/32” strip with the N7/3 but the decoder & stay-alive went in the bunker and that meant the side tanks and front of the boiler could be stuffed with lead so it tips the scales at 59gms. The Farish 08’s like the 03/04’s have cast metal bodies so that helps there.

 

Make new frames out of 1/16” brass strip. This would increase the weight a bit, but means shaping and drilling the chassis myself although I could dispense with bearings and just have the axles running in plain slots. Accurate drilling would be needed because there would be none of the ‘wriggle room’ possible with bearings which can be shifted a bit if disaster strikes. I am thinking not only of the wheels here but also the layshaft. You’ll see what I mean a bit further on with this saga.

 

Or for maximum weight I could attempt a ‘solid brass’ chassis. Now I’ve never made one of these nor do I have a small mill of the type ideally suited to his kind of work, so a lot of hand filing would be involved.

 

Using 1/16” strip would add around 3gms, so not a lot for the effort. I dug out some ¼”

square brass stock and found that maybe around 10-12gms might result. Much better but…..Hm...

 

So, I eventually decided to do it in stages. Build a ‘test’ chassis using the etched sides and see what happened. I could complete the body and see how much weight could be added. If it turned out the haulage wasn’t sufficient for my needs then a solid chassis could be made as a replacement.

 

Using the etched chassis sides I found that although the wheels will make the loco sit a bit higher they don’t reach the underside of the footplate, which is really good news. 0.5mm might not seem much but in 2mm can often make a big difference.

 

With that no longer a major issue I then altered the footplate and sub-base at the front, cutting out more of it to give clearance for the motor, and removing the strap across the middle where the gears will be located. These were done by scoring/cutting with the curved scalpel until cut through/fractured. It was a slow process but chain drilling in N/S would take just as long given how much harder it is than brass. I then cleaned them up with a needle file while holding the etches in the hand vice.

 

 

 

As the motor is double shafted the second shaft needed cutting back so it fits where intended. Although I would assume most would do this with a cutting disc in a mini drill I instead gripped the shaft in my hand drill and used a diamond needle file. Turning the shaft so the cut was equal around it.

 

 

 

The diamond files are a cheap set obtained from Machine Mart some years back, under a tenner, yet they are as good as (much) more expensive ones I’ve used. I find this method better/quicker than faffing around digging out and setting up the mini drill and a diamond disc. Less heat too. I always worry about small coreless like these so treat them with a lot of care.

 

The problem with the chassis etches were the axles holes weren’t big enough for the PB bearings. They were 1.9mm and needed opening up to 2.3mm. With 10thou N/S sheet trying to use drills would just rip and distort it. Broaches or taper reamers are best but not having any of a suitable size I just used a round needle file. This will seem very crude but sizing like this works okay by rotating the file anti-clockwise and opposite to the cutting edges. So a gentle action happens and an even cut occurs so the hole remains central. It also stops the file jamming in the hole. I kept checking the size using a bearing so none ended up oversized. I held the file in my hand drill with the etch in my fingers, so I could ‘feel’ the cut.

 

 

 

According to the members handbook specs for the gears M.04 14T running together need 5.6mm centres along with a clearance figure of 0.15mm, 5.75mm in total. The tooth depth for module gears is nominally 2.25x the module size, so 0.9mm for M.04. I hoped to mark and drill for the layshaft at between 5.75 – 5.8mm. This is why I use M.04, the extra leeway the tooth depth gives against the M.03’s. I found that it was just possible to site a 2.3mm hole below the top of the frames, well mostly part of it being above, to enable meshing with the rear axle. I couldn’t take it any lower to allow clearance of the wormwheel on the centre muff. I drilled the holes out to 1.4mm and then finished them to 2.3mm again using the round needle file which broke out of the top of the frame at the finished size.

 

 

I then soldered the bearings into the frames, flange on the inside.

 

 

 

I tested the gears in both frames to confirm the layshaft was located okay, that the spur gears meshed and ran together, pushing lengths of 1.5mm axle steel into the end of the muffs just enough to hold them in place. The ends of the steel were of course broken/chamfered to ensure they didn’t tear the bore.

 

 

This also allowed me to measure how much length there was for the chassis spacers. One short one at the back- 8mm, and a long one in front- 21mm. This was using the 7mm wide PCB.

 

 

Both were soldered to one frame, slightly below the top of the frame to allow a good fillet of solder on the top as well as underneath, then the second side was added using three lengths of ‘true’ 1.5mm axle steel for alignment.

 

 

 

It’s fairly easy to bend this steel out of true over a longer length with heavy handling so these were cut from new lengths and kept just for this job. They have proved very useful over time. This method is easy for seeing if the frames are square to each other and in the same plane. The slightest error shows up. Once satisfied I tack solder and re-check before running solder all along. I use phosphoric acid as flux along with 60/40 lead solder. The iron is my standard Antex 15w with a 1mm tip. It’s all I really ever use these days, with different tips. This stage is probably one of the most crucial in chassis construction. If it’s not square and true you’ll always be fighting an uphill battle whatever type of chassis you build, solid axle, compensated etc.

 

 

 

 

 

 

 

After checking the wheels in the chassis I again tested the gears. Here I hit a problem. Despite my best efforts and checks one of the layshaft holes was a bit ‘out’ so the layshaft wasn’t square to the frames/axles.

 

 

This required me to de-solder the bearing, ease the hole forward with the round needle file, and re-seat the bearing. This did the trick and all was thankfully aligned correctly. Thank goodness.

 

 

 

At this stage I worked on the gears, filing the muffs down a bit so they were an easy running fit between the bearings, the final gear muff having about 0.5mm side play. So they would spin easily with finger pressure, and with both in the frames spin the frame around them by holding an axle or layshaft. I do this to make sure the motor has the least possible drive load/friction to cope with. I also usually chamfer the outside tooth edges of the final 14t so they don’t ‘catch’ when rubbing up against the worm wheel. Just running a flat needle file around at about 60 degrees.

 

With this done I re-checked how the footplate fitted and discovered there wasn’t sufficient clearance for the layshaft bearings so a bit more of it was filed away to suit.

 

 

 

 

 

Bob

 

[Izzy]

 

A Hunslet 05 in 2mm – pt 4

 

Carrying on with the footplate yesterday I decided to check how much room was available in the cab area for the decoder and stay-alive pack. Luckily I have a spare CT DCX76 to use and found it would sit sideways on top of 4 D case 16v 220uf Tantalum capacitors (so 880uf) which would also just fit in standing long edge on. Nip & tuck but possible. It will depend on how far into the cab area the gears protrude. Not much I hope. Three tantalums (660uf) would do if the space proved too tight once the other bits were added, resistor/diodes. It would all sit just below window height, well that’s the plan, not too visible.

 

 

 

This gave room to shift the rear attachment point forward. In 4mm the recommendation was to use 12ba and there was probably enough room. Go down a scale to 2mm and 16ba might just squeeze in, but moving it forward would allow me to use 14ba. In this I was mindful the front and rear bolts fixing the body and chassis together would also be used to hold the keeper plate strip in place. There’s not the space to have separate ones at the rear. I might at the front, tap the PCB 14ba etc. I’ll see how it goes.

 

Anyway, I was able to add 2.5mm wide strips to the inside of the rear footplate and baseplate. These were cut from the etch that is supposed to be the cab floor and soldered to the chassis to enable the cab to be glazed and crew added after painting. With a split frame chassis this isn’t going to happen… A bit of PCB will be used instead on which the tantalums etc. sit as with the N 7/3 since it can be electrically gapped. I suppose plasticard could be used instead and might be thinner, keeping the height down. I used PCB in the N7/3 for electrical connections. Might need to again here.

 

 

It is the baseplate that the nuts are soldered to since it sits on top. Once the body is soldered to it and completely finished I envisage soldering it all to the footplate. Whether this will happen is another aspect that will only become apparent when I try it. What I don’t want is there to end up with a gap between the footplate and the body. This is the potential downside of not soldering the body parts directly to the footplate. I could end up doing that, removing the baseplate. This is all speculation of course, but I do try and anticipate where problems might occur and allow/plan for them when I can.

 

 

 

Having done this I turned back to the chassis. The next job was turning the bearings into slots, for my drop-in wheel system. Perhaps I should explain that I have only ever used this basic kind of chassis construction since the late 1970’s. With sprung hornblocks, compensation, machined bearings running in milled slots in the chassis etc. in a variety of scales. The common factor is the use alongside this of ‘press on’ wheels. In other words not screwed on to axles like Romford/Markits (4mm) and Slaters (7mm). So I got used to mounting and quartering wheels on their axles before fitting them into chassis and is what I feel most comfortable doing. No quartering jigs are used, indeed doing it all by eye/hand was often the only option anyway. It also allows me more ‘wriggle room’, which I often need. I can mount the wheels, get them running true, and if anything goes wrong they can be dropped out. Sometimes to get a chassis running as I want – I’m very intolerant of poor running - they'll be in and out more times than…...well you get the picture.

 

This ‘slotting’ requires the use of the round needle file (again) and a couple of others, a flat and a knife. I have a collection of needle files built up over time but have one of each shape which I use generally on a day-to-day basis kept in a separate wallet, ones I find I get along with best. These are virtually all Stubbs.

 

To do this slotting I start off with the knife to make the initial cuts, doing both bearings on an axle together at the same time because it’s almost impossible to do anything else anyway, open the cuts out with the flat, which is 1.2mm wide so less than the 1.5mm bore and no risk of opening out the slot too much.

 

 

 

 

 

And then use the round, placed into the bore and rotated as before anti-clockwise, pulling it upwards at the same time, while also holding the end with my finger, so it never touches the top of the bearing, where the axles will mostly run, and instead cuts into the slot.

 

 

 

 

 

Working slowly the cut can be opened up into a slot at the correct bore. Checking with a length of axle steel so none of it becomes over wide. That the axle eventually can just slide in and out. Changing during this process from one bearing to the other as the end of the file needs to be above/through the other to do this work. Each pair of bearings take about 10-15 mins to do. Time is not of the essence of course, just getting the correct result, but it’s not a terribly long job.

 

 

 

 

I then mounted the wheels on their muffs. The bore of the 3mm one with the final gear was very tight and needed running through with a 1.5mm drill a number of times to allow the wheel axles to even enter, so they fitted nice and tight and there appears no chance they will shift. I decided to use the small 2.3mm muffs on the other wheels and the fly-crank shaft. These were an easy fit by comparison, too much so. As a result I did what I normally do with most muffs, cross drilled them 1mm in the centres to enable me to drop a little cryno in after fitting the wheels and quartering them to lock them in place. You can see the small gap between the axles for insulation.

 

 

Quartering I do, as said, by eye, lining up either the spokes or the crankpin holes or both. It depends on the number of spokes. These 7mm have 12 so they all line up while other numbers may not. The larger the wheel the easier this job becomes, seeing the sight lines, so these are actually the most difficult to get exactly right.

 

 

 

In order to give the gear axle a little side-play I sliced of about 0.75mm with a scalpel. I should have done this before mounting the wheels but forgot.

 

 

With the other wheel muffs I cut off more, around 1mm. This is to allow room for Simpson springs to press on the axles. I don’t fit these to the geared wheel. With the springs going between the muffs and the bearings they will restrict side-play so cutting slightly more is better than not enough.

 

Although with a small wheelbase loco like this side-play isn’t really needed for getting around curves I don’t like wheel-sets to be too tight in the frames so always include a small amount. Things like crabbing, which can affect small, short wheel base locos is often cited as a reason to eliminate side-play, but it’s other aspects such as non-concentric wheels, axles too loose in the bores, bad coupling rods, poor quartering, that are the real culprits.

 

The other aspect with side-play allowance is the internal measurement between the wheel backs and the outside measurement of the frames/bearings. Although the btb is 8.5mm the wheels have a small rear flange and so it’s roughly 8.2mm.

 

 

The frames were 8.0mm over the bearings. As the latter protrude from the frames they could be filed down a bit to give some more side-play, and I took then down so it was 7.8mm.

 

 

You may just see the chamfer on the 14t gear wheel I mentioned earlier

 

 

At this stage I pushed the chassis up and down to ensure it all still ran freely.

 

 

 

I then decided the next task was to make up the keeper strip. Stop all the wheels falling out when I go to sort out mounting the motor! These strips I make from scrap etch. I did look at the loco etch to find something of suitable length and width but none was apparent. Deciding to have a little clean up, put away parts no longer needed, I spotted some coupling rod etches and found what I needed on them.

 

 

I could have cut a strip from brass sheet, but N/S is stiffer for this job, when it’s unsupported. And it’s waste not want not. I always cut up and save decent parts of used N/S etches for jobs like this. The 2mm association has now produced etches just of various sized strips but I haven’t tried one yet. Simple stuff like this can be very useful.

 

Oh, I also cut another couple of axle steel lengths for the fly cranks. 5.5mm length as the wheels are 11.3mm over total width

 

 

This brings up another thing I should mention. You might notice that I cut two longitudinal isolating gaps in the chassis spacers – on both sides. These are 2mm in from the edges so giving a 3mm strip in the middle. This is so bolts can be located here and the body will remain electrically dead.

 

The strip was drilled with 1mm holes to take 14ba bolts, and bent to shape with snipe nosed pliers to clear all the muffs but give minimal clearance over the geared one. Just not quite touching so no friction is generated. The others can drop about 0.5mm. I found the strip wasn’t long enough to reach the front bolt point already made, so I did have to drill and tap for a small 14ba in front of the leading axle. I used a 0.75mm drill here as the resin based PCB is fairly soft to ensure a good thread for the bolt when tapped. 0.8mm is the normal drill size.

 

 

 

Next up will be mounting the motor. It’s getting there.

 

 

Bob

 

[DavidLong]

Bob,

 

The following may be of interest. A couple of months ago I learnt of a couple of new decoders from Doehler & Haass which they have produced for Modellbahn Union. These are small N scale sizes decoders which, according to the information, have two small capacitors on board. I haven't had the opportunity to try one out yet although I do have a converted Farish 64xx for which one may be appropriate. Modellbahn Union info is here:

https://www.modellbahnunion.com/HO-OO-gauge/PD10MU-3-DCC-locomotive-decoder-with-6-pigtails.htm?shop=modellbahn-union-en&SessionId=&a=article&ProdNr=DH-PD10MU-3&p=802

They are also available via ebay and DM toys (an associate of Modellbahn Union):

https://www.ebay.co.uk/itm/384985473617

They are actually relatively cheap but of course the postage cost puts them up nearer the usual £30. D&H do generally seem to have a decent reputation. Somewhat surprisingly there don't seem to be any D&H agents in the UK  but as these decoders are made for a specific company that mat not make any difference.

 

David

[Izzy]

Thanks David, that's very interesting. A bit smaller than the Zimo MX617. The question would be how the motor control stacks up I think. I have heard the name before and believe it may be decent, but whether it's at Zimo/CT level would be key for me. The mention of the capacitors for data retention suggests to me it's not stay-alive motor type but I guess this kind of knowledge is more @Nigelcliffe level. Whether stay-alive could be added if not would be another question.

 

I'm just thankful I have the CT DCX76 spare for this loco given the current dearth of almost any type of Zimo. I have a larger Zimo MX622 spare as well, but it's 6-pin, as are a couple of Lenz silver minis which I could use until something better could be obtained if I was really desperate. They are small, but that's the best that I can say about them.

 

Bob

Edited September 28, 2022 by Izzy

[Nigelcliffe]

I think D&H are available through DCCTrainAutomation.    

 

I've never used them, but they have a reasonable reputation.   Try Carsten Berger's 1001-digital site which may carry some more information (in German).  

Most D&H decoders seem to have decoder positive and decoder ground available for stay-alives.  

 

 

 

- Nigel

Edited September 28, 2022 by Nigelcliffe

[Izzy]

A Hunslet 05 in 2mm – pt 5

 

 

I used Slaters10thou & 20thou plasticard to mount the motor. I say Slaters because it’s a hard variety and other makes vary, Evergreen being very soft by comparison, so how others would key to the chassis and motor might vary. I used Mek-Pak as the glue. I have ‘proper’ MEK (butanone) as well as others, but this combination works well for me in most situations. Other peoples experiences may of course differ.

 

However, firstly I mounted a worm on the motor shaft. This is one of the new white acetal 1mm bore ones, which as they are quite long, I sliced in half with a scalpel so it hopefully doesn’t protrude too far into the cab. It was a nice fairly tight fit, like the other black ones I’ve had in the past. I like the way they can be pushed/pulled on and off and along the shaft and retain this firm fit. However, as I had cut it in half I decided to smear a drop of cryno on the shaft before final fitting in position to ensure it didn’t move at any time.

 

 

 

 

Putting the motor on the chassis showed that with the worm-wheel's position the motor would have to be raised a bit. A strip of 20thou and another of 10thou sitting on the spacer and between the frames seemed to get a decent height and allow the worm to sit in the worm-wheel correctly. I then added 10thou strips 1.5mm wide followed by 1.0mm along the outer sides to make a shallow ‘v groove’ into which the motor sat. This I then fixed in place with a wash of glue

 

 

 

I tested the motor connected to a basic Bachmann layout set controller (not the best control in the world but quick and easy), to see how it ran. Not too bad. The mesh seemed okay.

 

https://youtu.be/z2XKoxKFvXs

 

With this confirmed I added 10thou strips up the side and on top to ‘box’ the motor in, running the wires inside as they would need to go to the rear. And sloshing more glue around to lock it all together. Very easy, crude, and simple. The overall width of this ‘box’ matched the chassis width to ensure it would slide up inside the footplate easily.

 

 

 

I then tack soldered the wires to the ends of the chassis for electrical pickup and tested it again on a short length of track. It ran okay but a slight ‘chuffing’ sound indicated that the meshing was a fraction too tight so I levered the worm end up a bit with tweezers. As the glue joints hadn’t completely hardened off at this stage there was some ‘give’ in the structure and then it settled down to run okay-ish. A bit stuttery due to just trying to move using only the driven axle and the lack of traction.

 

https://youtu.be/GaYMxtPPzjM

 

Satisfied this would become acceptable once all else had been sorted I turned to making the coupling rods, but to do this I first needed to make up the jackshaft and flycranks. Two lengths of axle were cut 5.5mm long, the overall outside measurement of the wheels being 11.3mm. The outside faces of the flycranks need of course to roughly match this, and there is also the air gap between the axles required. I would again use a small 2.3mm muff. Gluing a small disc of plasticard to the end of one does ensure they can’t touch if pushed in too far.

 

In a previous post Nigel (Cliffe) very kindly confirmed the crank throw of these 7mm wheels as being 1.5mm, which as luck would have it were also present on the etch for the flycranks. There are three sizes offered. 1.7,1.5, 1.83, which of course relate to the equivalents needed in 4mm for different make wheels in that scale. I lined them up and layered/soldered them together before sorting out sizing the holes. There are three layers.

 

 

The small crankpin holes were just under 0.4mm so opening then up to 0.55mm allowed the flanged crankpins I had to fit, 0.5mm being too tight. The axle holes were quite a bit under 1.5mm. These I opened up to 1.4mm with a drill and then used the round file to finally size them for a good firm fit on the axle steel. I used a spare length for this with the end well chamfered only sizing from one side once the steel just entered the bore on both sides, the file of course being tapered. Both the crankpins and axles halves are of course soldered into place so this helps with any slight errors in sizing. These flycranks are just a simple push fit into the muff. I don’t usually secure them in any way since as Nigel has also remarked previously, in essence they just really ‘go along for the ride’. I just have them quartered correctly with a loose fit of the coupling rods on them. But I do this with the rods on all crankpins anyway, which I’ll come to shortly.

 

 

 

I took this shot before filing back the rear of the crankpins so they were level with the rear of the flycranks.

 

I had decided to try gluing the crankpins into the wheels with cryno as has been discussed on, I think, the 2mm VAG. Those on the N7/3 I had soldered into place as with the mk4 wheels. This I do before fitting the wheels on the muffs. With gluing them I chose to leave this stage until later, when the wheels were on the muffs and quartered. I thought it might make things easier. Here I hit a small problem, and I can’t really work out why. The holes in the wheels were bored 0.5mm. A 0.5mm drill went through okay. A nice fit, not loose. The pins measured 0.5mm, same as the drill shank. But even with chamfering the ends of the pins I could not get them to fit in. I’d had no issues with the wheels for the N7/3 or indeed the mk4’s. Hm. Were the new pins I got a very slightly different size to before I wondered? Tiny differences can matter, I’d never really had to measure or think about it before. Out with the spares left from the last pack. No, all exactly the same size. Wouldn’t fit either. Okay.

 

I couldn’t use a broach to open up the bores enough to get the pins to fit, there wasn’t the room as they were now locked and quartered on the muffs, so I took the only other course open to me and drilled the bores out 0.55mm. 0.05mm is 2 thou so I hoped it wouldn’t be too much. It wasn’t thankfully. The pins fitted in just the way they had before with previous wheels. Really weird. A drop of cryno in the bores and the pins feel locked in place.

 

 

 

 

 

Finally being able to now fit the wheels and flycranks in place revealed that there was more than enough room to spare between them. More sighs of relief!

 

 

So, now onto a job I had not been looking forward to right from the start, the coupling rods. These had looked very fine, and thus also fragile, from first seeing the etch. I immediately thought I would have to make more robust replacements because I just wouldn’t be able to cope with them. I struggled with those produced for the Farish Jinty/4F conversions and eventually had to go with the larger than scale but more robust ones on the association 3-205 etch due to my inability to handle things carefully enough. I try my best but…..

 

 

However I decided to try with them first at least, until I bent/twisted/wrecked them. See how far I could get. It wasn’t easy. They are if anything even finer than those mentioned. I managed to get a 0.5mm drill through the holes while they were on the etch, but they started distorting going any further. Oh dear. One layer being half etch depth except at the crankpin bosses didn’t help. So I then cut them out and soldered them up, hoping I could open the holes up afterwards, when they might be a bit stronger. Otherwise it would be on to plan B.

 

 

The basic design is individual rods meant to pivot around the crankpins, to allow for springing/compensation etc. the frames being etched to allow slots to be formed to fit hornblocks. In 4mm of course. So they needed soldering up in a way they became solid whilst flat and in a straight line. As they are lapped over the crankpin holes this means solder fills these holes as I did this. I flooded plenty of solder into all the joints, checking as best I could they matched the wheelbase, because making ‘cut & shut’ coupling rods to suit odd locos over time, like those made for my 03/04 and posted about earlier in this thread, I know that if not given enough they can end up weak at these joints and liable to bend/fracture at these places. As they were being soldered at the crankpin bosses I couldn’t see a way to use pins etc. to set the wheelbase distance through the crankpin holes. Use pins smeared in oil might work, but ran the risk of spreading into the joints and preventing a good soldered joint between the rods themselves.

 

It went better than I had feared. Although very small they seemed to have enough strength. Holding them with a pair of tweezers on the cutting mat, I drilled the crankpin holes in stages. Firstly with 0.5mm to establish them, followed by 0.55mm and then 0.6mm. At each stage I tested them on the loco to see if they fitted. That they fitted okay at middle dead centre, 90 & 180 degrees. No tightness or binding over this ‘dead centre’ position. Not finding them doing this easily I then went to 0.65mm. I quite expected the rods to start breaking down, not enough meat around the bores for them to cope, but they didn’t. It still wasn’t enough. They now went over the pins but on the track the chassis wasn’t entirely happy. Something seemed amiss. I checked and re-checked, that the crankpins weren’t bent out of true etc. and then finally tried 0.7mm. This is the size I normally use, a quite sloppy fit some may find surprising. When even this didn’t work I thought it was onto plan B. That the crankpin holes must be out fractionally even though I couldn’t see any error up against a ruler.

 

Although I’ve never gone this far before, giving it one last try, going for broke, I ran through with a 0.75mm. The rods held!  Here's a size comparison with a ordinary pin.

 

 

And what’s more the chassis then ran acceptably enough that I decided to make do. Take a chance knowing that the option of plan B would always be there. And especially as making the chassis like this, a lightweight, was all a bit of a shot in the dark anyway.

 

 

 

 

The video is just a brief look at the running I did with it, some worse, most better, still quite variable without any weight and lacking Simpson springs let alone a decent DC controller or DCC decoder + stay-alive. Hope and expectation lives on……

 

https://youtu.be/hm9lM0N6kDE

 

I think I might play with the body a bit more now. I won’t finish the chassis off until that is done just in case alterations may be needed that I am unaware of at present.

 

Bob

 

* sorry, can't seem to embed the videos. Hm.

 

Edited October 1, 2022 by Izzy
video link issues

[Caley Jim]

I've always found that a bit of slop in the coupling rods never goes wrong. I would suggest that any remaining slight stiffness will 'run in' in time. 

 

Jim 

[Izzy]

Yes Jim, that’s what I’m hoping. It’s surprising what a bit of running just up and down a short track will do, especially when I can add a little bit of weight into the mix. 
 

Bob

[Izzy]

 

A Hunslet 05 in 2mm – pt 6

 

I’ve now started back on the body. Looking at the design concept of the separate body base I thought perhaps I aught to make sure the cab and engine casing when assembled fitted onto it correctly when joined together. I still worried that in this scale getting it to seat flat and not end up with gaps between the body and footplate could be an issue.

 

Firstly I decided to fit/solder the engine casing doors in place. This would help strengthen it when soldering either to the baseplate or footplate if I dispensed with the former. I drilled out the handle holes 0.3mm to make sure they were clear. The aim is to use 9thou steel guitar wire for all handles, handrails etc. Next I also chose to cut out and fit the windows in the cab parts, front, back, sides, doors, while they were ‘flat’, thinking this might be easier than when assembled together. These window frames are fitted into half-etch rebates but are quite fine. It also seemed pretty essential with the cab front as the windows went right up to the edge so there was virtually no ‘edge’ here, just a thin bit of half etch. After cutting them out of the etch I had to very carefully hold them in the hand vice to be able to file of the tab residues. Some still distorted and had to be gently straightened with tweezers. I laid the sides over these frames and soldered from the rear to allow solder to flow into the joints and fill any gaps on the outside. I cleaned up in my usual manner with scalpels and files, scrapping away excess solder. I do this at every stage of construction on anything I make, on the outside visible faces and the inside if really excessive. I sometimes use fibreglass pencils as well. When it looks clean I feel mistakes are easier to spot and rectify before going any further when it might not then be possible.

 

The cab front and rear fit into rebates on the sides. I made a mistake here. I didn’t assemble and fit the cab doors at this juncture, which it turned out would have been far easier than once the cab was together. Because these doors are inset, and the cab sides slope inwards at half-height, there are tapering wedges that sit in half-etch rebates in the doors, so they stand vertical. Trying to fit these door assemblies once the cab had been put together was quite difficult, however I didn’t want to have to take the cab apart as it had gone together okay. Fitting the doors also makes the sides stronger, less liable to warping under finger pressure. There are etched tabs to keep the door gap until they are fitted but these can warp/collapse as they are just half-etched.

 

 

I then fitted the radiator front and rear former panel into the engine casing. The front needs the edges rounding off except at the top edge.

 

 

The design is as I’ve mentioned before that registration holes are present in the cab front and rear former to line them up. I soldered 0.35mm brass wire in the cab front so I could plug the two sections together, and then solder them up once it was checked that all was square and true. Since this meant there would be more metal involved I changed the tip on the iron for a bigger one to ensure the joint went quickly. This turned out to be another mistake.

 

 

 

I checked it all and on the drawing for overall size, that it all was correct and square, and then used the iron.

 

 

Well, the two plates sweated together okay, but the heat transfer ‘sprung’ undone the rear engine casing on both sides. I managed to get it back into place both sides, but then discovered all this had shifted the whole lot, and the bottom of the casing now sat higher than the cab. So I had to first unsolder/remove the casing completely, and then the rear of the casing panel from the cab front. Worrying all the time this would ‘spring’ the cab joints apart…….

 

Initially I began to clean things up to go through the process again but then thought, hang on, if I was scratch building the loco would I be doing it this way? No. I’d just be soldering the basic engine casing straight to the cab front, lining it up with a bit of tack soldering first. So that’s what I did. Oh, and I also went back to using the small tip on the soldering iron. To better control the heat spread. I know a lot of steam loco’s etched kits are designed this way, fireboxes etc. usually joined together with a single bolt through the centre, and I’ve done the odd one or three of them in other scales, but it can be problematic at times, as this turned out to be. Another time it would be plain sailing…..well mostly….

 

Turning to the base plate I decided to see if I could fit it. I set it so it was very slightly in from the edges to try and ensure that it didn’t keep the body edges from mating with the footplate. Adding it did seem to make the body feel firmer. Bolting the footplate and finding no gaps I could see I then soldered the two together from the inside where the two layers were visible. With plenty of flux the solder was drawn to the outside edges. I only did the sides, not the front or back, so the bolts didn’t get soldered up solid as well.

 

 

You will see that I've also cut a bit out of the cab front to clear the worm and gears and provide a bit of space for the motor wires.

 

Trying the body on the chassis and comparing it to my blue Farish 04 with it’s etched chassis I was very pleased to find that despite using larger than scale diameter wheels it’s footplate was still lower, as it should be. These locos, although classed as 05, were quite a bit smaller in several ways than the 03/04’s.

 

 

With this sorted I then went about adding the bufferbeams and buffers. As I wanted to use DG’s I first made a slot in the bufferbeams into which the couplings could be fitted. This was a slow process, chain drilling N/S with a 0.3mm drill wasn’t either quick or easy. After breaking one I filed a 60degree chamfer on the opposite end of the shank with a diamond file and drilled with that. I then cut it into a ragged slot with a sharp scalpel and sized it with what remained of the drill flutes proper until the shank of the DG could be pushed through. As these bufferbeams are two layer, a 10thou back with an etched front, I just did the back layer, sweated the two together, and then cut the thinner front layer through the slot with the scalpel to make the front one, again using the broken drill to get the right size.

 

 

The bufferbeams soldered to the footplate well and felt solid. They go on the ends rather than beneath. I’d got some 18” LMS square base buffers from the association as they seemed the nearest match. However the holes in the beams were larger than the shanks, and larger again in the rear layer than the front one, so soldering them in while keeping them square to the footplate proved tricky but they added more strength to the beams in helping to keep them square to the footplate. I ended up not getting the slots level….a twist of the coupling should sort that, hopefully.

 

This shot shows those doors.

 

 

It’s beginning to look quite respectable now.

 

 

 

The next task will be sorting out the decoder and stay-alive and the pcb they sit on in the cab. I need to get this aspect done to ensure it fits into the space. Although your supposed to fit the roof permanently in place I will make it to plug-in so I can sort things without having to drop the chassis out if I need. Being able to do both might be handy, for painting etc.

 

Oh, weight.....  

 

While I had it out I put both the Farish 04 and the Hunslet on the scales. The 04 comes in at 32gms. The 05 at just 13gms, so there is space to find to add some lead sheet. All around the motor is possible, top, sides, front. And at the rear of the cab below the window line. This is why I want to tackle the decoder next. Get it and the tantalum’s etc. in the cab. And hopefully (that word crops up a bit doesn’t it?) not to far above the window line or highly visible. We shall see.

 

Bob

 

[Richard Hall]

Bob, I am following this build carefully and learning a huge amount from it. Even little tricks like the plastic sleeves over the crankpins to hold the rods on for initial testing. Thank you for posting in so much detail, absolute gold here.

 

Were the 05s scrapped early because there weren't enough drivers thin enough to squeeze through the cab doors? They can't be much more than a foot wide.

 

Richard

[Izzy]

19 minutes ago, Richard Hall said:

Bob, I am following this build carefully and learning a huge amount from it. Even little tricks like the plastic sleeves over the crankpins to hold the rods on for initial testing. Thank you for posting in so much detail, absolute gold here.

 

Were the 05s scrapped early because there weren't enough drivers thin enough to squeeze through the cab doors? They can't be much more than a foot wide.

 

Richard

Thanks Richard,

 

I’m grateful you said that because I have wondered how much to say, not wishing to, as they say, ‘teach granny egg sucking’. The plastic sleeves are outer wire, the trick being getting a size that’s a decent tight-ish fit. So far they, and the wheels/rods, have been on/off, in/out, of the chassis four or five times as I do things. That’s why I could never contemplate fitting wheels in a ‘fixed’ chassis. I don’t know how people manage it, real skill I could never match.

 

Yes, they are narrow aren’t they. No idea why, or how anyone got in. They scale out at under 18”, roughly 2.8mm. When you think the average house door is 28-33”. Turn sideways, take a deep breath, pull in your stomach…..

 

Bob

[ShadowinLinby]

There is only one answer to that conundrum Bob - practice makes progress. 

 

ChrisB

[Izzy]

A Hunslet 05 in 2mm – pt 7

 

For a very long while I shied away from fitting stay-alive. Recently I’ve read comments that if you have clean wheels and track it shouldn’t be necessary but I don’t live in that perfect kind of world. I’ve managed in more recent times to make and fit stay-alive to most of my 2mm locos, all except the bogie diesels in fact, so fitting one in the 05 was considered part of the basic spec.

 

As I was fortunate to have a spare CT DCX76 decoder with stay-alive wires already attached to use I felt that fitting it into the cab and sitting on top of the tantalum pack would be the way to go. It’s turned out to be a slightly longer job than I had anticipated and hasn’t worked out quite as I expected, rather more as I feared, which isn’t the end of the world, but does impact where weight can be added. But I’m extremely glad the decoder was to hand because once I got down to it I found that virtually no other decoder would have fitted in the space anyway, even the next smallest being too large. This will all become clear further on.

 

I started off by making up the stay-alive tantalum pack. I had hoped to fit in four of these SMD 16v 220uf D case ones, but soon realised that with the Zener diode and Schottky diode + 100R SMD resistor three were the most that could fit sideways standing on edge. This is thus 660uf and what I have used before so good enough although more is always better. All I’m after is a bit of help over tiny specs of dirt etc. not running on over a carpet etc.

 

The capacitors I strapped together with a piece of magic tape before adding PB wire down both sides, making sure of course that they were all orientated correctly. I haven’t always…. whoops.... Bang! Done once and never forgotten! These wires are bent one end to add the 16v mini-MELF Zener diode.

 

 

 

At the other the mini-MELF Schottky diode + SMD100R resistor attach to the positive leg. This is connected to the common positive (Blue wire) while the negative connects to ground (I use white wire here – there’s no lighting).

 

 

Once I had checked the fit I added some insulation. I used Tamiya masking tape as I have before. More will be added around the ends once the wires are connected. I checked for easy passage through the body. I had to file a bit more out. And a bit more still later on.

 

 

 

 

 

 

I decided to do as I had with the N7/3 and fit a one-sided PCB pad to the chassis on which to sit the stay-alive pack and connect all the wires up. This was split insulation-wise as I did with the chassis spacers, as well as another section to connect the motor leads to those of the decoder output. I thought (a wonderful thing) that I had taken a shot of this, but no I hadn’t. Not before soldering it in place. So here as a replacement is a diagram to help explain.

 

 

With the pad soldered to the chassis the bottom holes are track feed. The upper two each side join the motor wires and the decoder motor output. I never never bother which pairs I connect, which way around they are. The track feed doesn’t matter as it’s DCC while if the loco runs the wrong way adjusting cv29 is quick and easy, well with my Sprog/Decoder Pro/JMRI anyway, which is all I mostly use for programming.

 

 

My early version Sprog 2 is quite probably one of the best investments I have made. If I could only have one piece of DCC equipment it would be it, no question. A golden rule I have is never, ever, to run any loco from new with a decoder fitted, even RTR, until it has been on the program track and read a bit just to confirm no problems, then run using the Decoder Pro Throttle. If there are any issues with wiring etc. then a read on the program track will return ‘odd’ readings, either ‘loco not found’ or the manufacturer or loco address will be faulty, i.e. ‘no such maker’ or the address will be a string of weird numbers ‘147935’ or such like, nothing you would have set, 3 being of course the default as-delivered address.

 

 

Because I hadn’t yet fitted any Simpson springs to the front two axles I had to press down on the chassis to get it to read properly as the program track output is just purposely signal level low voltage. There will/should be an ’ack’ response from the motor as it’s read/written to. Sometimes they will move quite a way down the track……

 

As the CT decoders aren’t happy being programmed with a stay-alive connected or being DC enabled when they have the former, this has to be done first. At this point I discovered that it just wasn’t really possible to sit the decoder on top of the stay-alive pack, there was just too much wiring, I couldn’t tuck it around despite using the smallest/thinnest wires I could find. I had other ‘fun’ here.

 

 

 

Trying to manoeuvre all the wires, first the two stay-alive wires came off…..which meant more tricky soldering and re-checking on the program track that it hadn’t gone pear-shaped, followed by the same occurring with the main decoder wires…...meaning I eventually had to decide to site the decoder on top of the motor, where I had placed those in the 04 and 08’s. This meant less space for weight.

 

 

 

To illustrate just how little space there is I made a near fatal mistake of not covering the decoder with insulation before plonking the body on and testing it on the track. Immediate short! The wires at the solder joint with the decoder were touching the top of the engine cover. I also put tape on the underside of the body front and back to insulate the chassis from it. Something neccesary with split-frame current collection.

 

 

 

Now the CT decoders are not only some of the smallest in width and girth but also thickness. The CT DCX76 is 1.4mm. I know of no other decoders as thin. With a layer of Tamiya tape all is well, thankfully, I escaped my mistake by the skin of my teeth, it could have been a different story so easily. But without lowering the motor somehow, or using the smaller 6mm diameter coreless motor, I don’t see how any other decoder would fit here, and of course they can’t be more than 7mm wide anyway. Hm. Tricky.

 

 

And the space is the cab isn’t large either, 14mm x 14mm internally. Sounds enough and I suppose one of the very small double thickness/half length Zimo’s might fit. It depends on whether you’d want to fit stay-alive as well of course. A real balancing act. This is just a heads up for anyone contemplating making one of these 05’s and using DCC. At least this way the cab is clear.

 

The stay-alive is held in place on the pcb with some d/s tape

 

 

 

 

 

Anyway, I decided to test the loco on Priory Road at this stage. Just to see how it looked and ran without any real weight. But then an issue occurred that has meant further work has been put on hold for a few days. The stay-alive pack in the N7/3, which was sitting on PR, blew a tantalum. This is the second time this has happened in recent months, following a similar incident with the Ivatt 2MT. There are some worrying similarities so investigations are now under way.

 

Bob

 

 

Edited October 10, 2022 by Izzy

[Allegheny1600]

Hello Bob,

Wow, wow and thrice wow! 
Your work on this gorgeous little shunter is quite amazing really but now when it comes to the fitting of these electronic gubbins, I am in awe.

 I feel your pain in part as I have struggled with a small H0 steam loco but compared, I have masses of room and nothing to complain about. I have also invested in a CT decoder and know they are exquisite - and expensive so it was very fortunate you didn’t release the magic smoke!

Keep up the good work,

John