Some RTR rolling stock for All Saints East

[Izzy]

If you do drill & tap mazak then can I suggest caution with doing it, in respect that it isn't an easy metal to work. It tends to stick to cutting edges/surfaces, a bit like an harder version of whitemetal, I've broken a few drills/taps because they got stuck - as with the latter. So frequent withdrawal (every couple of turns max) to clear the swarf is needed. Makes it time consuming though. PCB pads are easier where it works.......

 

Izzy

[sb67]

Thanks Izzy, I'll bear that in mind. Didn't realise it was mazak, when I tried sanding it prior to drilling it hardly made a scratch so I'm not suprised drilling will be tough.

Steve.

[Izzy]

 

Well, there is always the chance that it is something else, but most castings of this nature are usually it. But the composition can vary considerably like most metals/plastics from soft/buttery to rock hard. Hope you work something out anyway.

 

Izzy

Edited February 10, 2019 by Izzy

[Izzy]

 

Bachmann 03 chassis re-build.

 

It's been a while since I posted anything on this thread. Not because I haven't been doing anything, quite the opposite in fact, but it's either been actual work on the layout itself, or making things in another scale altogether.......

 

Anyway, the reason for this post is by way of an update to the Bachmann 03 conversion.  The other day I finished the latest alterations to the layout which involved yet another track re-build, picked it out to be the 'test' loco to have the first run over the new install, and it rather shuffled along in a manner that just didn't seem right. A little humping/wobble once every revolution of the wheels and more noticeable at some speeds than others.  The track seemed fine so I put it to one side and used the 08 instead. I am quite spoilt for choice really for such a small layout, 03/08/15/24/31 for diesel traction plus the J15 as well as the W&M railbus and Cravens 105 DMU.

 

Once it was on the workbench turning it over revealed the problem. The plastic 3-layered cosmetic frames I had fitted onto the outside of the Bachmann chassis had warped badly and come away from it.

 

 

A strip down made it clear replacement frames would have to be produced in an alternative material that wouldn't be subject to warping like this.

 

After some thought and much measuring of different material thickness I decided to use some cut from thick PCB sheet which I had to hand. I had two different PCB sheets, both obtained from Maplin, one SRB, the other Glass fibre. Although it is a bit harder to cut I used the latter on the grounds it might be more resistant to warping, something I was keen not to happen again. Since the sheet was about 2/3rds the thickness of the previous 3-layer plastic overlays I glued a single plasticard layer to the outside of it. I glued the frames to the Bachmann chassis with cryno after adding the brakes and sandboxes to them as I had done previously.

 

I would post shots of the new frames and the re-built chassis but I seem to have mis-laid them. If they surface at some stage I will add them to this post. However I hope my experiences will serve as a warning to avoid using all-plastic layered overlays if you can to prevent suffering these kind of issues.

 

Izzy

 

 

[Izzy]

An N7/4 for All Saints East.

 

The Oxford Rail N7’s first arrived quite some time ago. When the BR livery versions appeared I thought about getting one for a while but question marks over the coreless motors being used and whether conversion to P4 was feasible meant it went no further at the time. More recently I obtained one secondhand at a reasonable price having learnt in the meantime that conversion to P4 appeared possible. As with my Hornby J15 the idea was to see if it could be done simply by machining the wheels to run on track to P4 standards, with the backstop that should this not work out then purchase of suitable wheels from Gibson would be possible.

 

There is no doubt that it is a nice looking loco and the body finish is to a good standard as with most present day RTR. I had hoped not to have to alter the body save to add screw couplings to ensure no damage was caused to the nice BR mixed traffic lined livery but some grinding away to gain enough clearance for the wheels and coupling rods has proved necessary. Thankfully no damage to the finish occurred, a cradle in 5mm foamcore being made to hold the body firmly and safely upside down to assist with this work.

 

I don’t think I have seen a complete chassis strip-down of one of these online, if there has been I’ve missed it, so I’ll start off by doing just that. The chassis is held in place by three screws. One at the front underneath the coupling pocket, and two towards the rear one each side. The body is a mix of a cast footplate and internal sections mated to a plastic outer shell. The chassis is a single casting with a two layer plastic keeper plate incorporating the pickups. The motor is held in place with a plastic cover. There is another cover for the gear train. Both held in position by screws.

 

The motor is a small double shafted coreless just 10mm x 23mm in size and fitted with a flywheel that couples to the worm in the gearbox via a U/J. The worm also has brass bearings on it’s shaft. It’s all nicely done, the use of the U/J removing any end thrust pressure on the motor. This is advisable with many coreless motors since most are not designed to cope with and absorb it in their construction.

 

A major difference is that the chassis has the leading driven axle and the rear carry wheels sprung using centrally placed coil springs bearing on the axles. But not just downwards, they have movement above the median as well. I have to say I am not particularly keen on such a design arrangement as it can lead to the ‘nodding donkey’ syndrome. Luckily the wheels run true and weight distribution appears such that enough is over the middle and rear driving wheels to prevent this happening.

 

Again as with the J15 the gearing was stuffed with lubricating grease. This had dripped down into the keeper plate which contains the phosphor bronze pick-up strips which bear on the back of the wheels. The multi-stage gearing produces a 50-1 reduction by my reckoning, which gives reasonable slow running and is pretty essential I feel with such a small motor being used for the weight of the body. Wiper pickups are used on the driven wheels as stated. The carry wheel is dead. The drive is to the rear axle.

 

There is a pcb at the rear with an 8-pin socket. The DCC blank fitted has a largish capacitor, presumebly to smooth current going to the motor on DC.  There are brass sprung plungers that connect this pcb with the keeper plate. I cut most of this off, just leaving the plunger connection. Later I soldered the plungers to the pcb to improve electrical reliability.

 

 

 

 

 

 

 

 

 

 

 

 

 

I did find it possible to machine the wheels in a similar fashion to the J15. Less thinning of the fronts were required so the moulded centres were not touched which made things much easier. However longer replacement axles were required. The originals were 2mm splined so after running through with a 2mm reamer plain 2mm rod was not a tight fit and roughing them and using loctite was required to get the wheels to key firmly on them. The final drive gear was drilled through at an angle on the axle and a pin fitted, some 0.7mm brass rod, to lock it in place on the axle with again some loctite. I also fittted brass tube spacers between the wheels and bearings to reduce excess sideplay.

 

 

 

However initially decent and reliable running proved elusive due to a combination of excessive slop in the coupling rods along with intermittent current collection.

 

The coupling rods had very oversized holes for the crankpins. What was even worse the leading and centre ones were slotted lengthwise. I could not get decent smooth consistent running until I sweated 10thou N/S sections behind the bosses and re-drilled to get a much closer fit on the crankpins. The crankpins are turnings fitted in from the rear of the wheels and these were shortened before refitting. This involved drilling right through and running a 12ba tap in to give a decent thread length for the hexagonal headed crankpins. I may make replacement items as with the J15 at some point.

 

 

 

The current collection issue was traced to the springs in the chassis. These seemed to have been stretched, making them too strong and lifting the middle sets of drivers up off the rail and thus loosing electrical contact. So these were squeezed down using pliers until they were more compact, reducing their strength and allowing better rail contact and current collection. However the phosphor bronze sheet wipers still didn’t seem to work that well, so were eventually cut off and replacements in 0.45mm brass wire made and fitted. The difference was quite noticeable, but complete reliability was not obtained until a stay-alive pack was added. Luckily I use DCC, and also fitted sound, which I will describe later.

 

The chassis is very narrow, just 11mm, perhaps to help allow sufficient play for the loco to get around tight curves in OO. I decided to add false frames to make it look a bit better. 3 layers of black plasticard I had to hand each side and giving a width of 15mm overall. The section behind the carry wheels is narrower. Again three layers of the black plasticard were shaped and fitted into the circular recces to keep the narrower than the main frame relationship. These parts were all attached to the main chassis sides with d/s tape as glue of any kind would not keep them in place and only served to cause them to warp and pull away. It can now get smoothly through a A5 crossover without too much throw of the rear.

 

 

I had not thought that any grinding away of the body to provide clearance for the wheels at the wider P4 measurements would be needed. I was wrong. While the front and middle splasher internal distance is 23mm the rear one is too tight at about 22mm. A set of wheels will just fit but allows no room for error. So I ended up using a diamond cutting disc in a mini-drill to widen these. I then found yet more grinding away was required to clear the coupling rod bosses at the wider gauge setting as well as reducing the bosses in size to help with this.

 

 

Once decent running under DC had been obtained I fitted sound. The sound project used was a YouChoos N7 immersive drive on a Zimo MX648. It was fitted with a small stay-alive. These were both located in the bunker. There is not enough room to use the larger MX645 with it’s on-board stay-alive circuits. It seems most sound installs also fit the speaker in the bunker. However there is a lot of empty space under the motor and so I placed a 15mm x 11mm planar speaker in a custom box – black plasticard cut to size and shape – in the rear half inside the tanks. This sounded better than in the bunker. Tamiya masking tape was used to seal and insulate everything, giving it a matt black coat of paint where necessary.

 

 

 

 

 

 

 

With a driver & fireman added into the cab the job was finished. Oh, and some coal glued into the bunker, this perhaps being the weakest part of the loco looks wise, the moulded finish. It now runs well and looks and sounds good, so I am pleased I eventually got one.

 

 

Izzy

Edited August 15, 2022 by Izzy
restore images

[Izzy]

Just to say I have been able to reload all the images to this thread.

 

Bob

[Izzy]

 

A Railroad Class 31 re-motor

 

On the first page of this thread I described the conversion to P4 of a Hornby Railroad Class 31 along with some body improvements. Although it was okay performance-wise it wasn’t brilliant at slow speed which was what was needed for my small plank type shunting layout.

 

 

So last year I managed to obtain a ‘full fat’ mazak rot version (5512) at a decent price. The intention had been to take out the motor and drive parts along with the bogies and transplant them into the railroad one as others have done. However I found that the body & chassis damage was quite minimal, very minor cracking of the cabs which could be cured by re-gluing, while cleanly cutting off the front bufferbeam sections from the chassis and fitting them to the body instead meant the whole loco could be used since the main chassis seemed totally unaffected by the rot. The chassis had just failed at the weakest, thinnest point, the front part under the cabs which includes those bufferbeams. All I had to do was then machine the wheels to run on P4 track and it was job done. I did however remove and ditch all that rotating fan gubbins to provide plenty of space for the speaker and decoders and also ditched the circuit board as the lighting connection parts had failed. I could have re-wired it all but wasn’t bothered about the lights, not ever using them. It is always something I can re-visit in the future and sort if desired at any time.

 

The TTS sound decoder was moved over to the new loco but was found not to control it very well. Eventually I did another ‘piggy back’ job as I have with several other diesels using TTS chips and used a spare Lenz silver mini to control the loco with the TTS just providing the sound. This then meant the original railroad model was spare and no longer needed.

 

Recently I decided to try and sell it on the RMweb classifieds. No sooner had I listed it than while giving it a final run before packing it up ready should a buyer emerge than the motor just packed up, went completely dead. In hindsight perhaps this had been on the cards without me realising as the slow speed running had been getting worse. So I then of course withdrew the loco from sale.

 

This left a dead and useless loco. I did consider trying to sell it as it stood, needing a new motor, which can easily be obtained from such as Peter’s spares. But I was also intrigued as to why the motor had failed, and why the loco didn’t run better than it had. Had I got one that had a less than perfect motor to begin with, was that why performance was not as good as I had hoped? Or was this just basically railroad standards? I had no way of knowing and didn’t feel I wanted to buy another motor myself if the latter was the case. It would just be more money down the drain. I also had lots of spare Mitsumi double-shafted motors and wondered if perhaps I could re-motor it with one of those. An experiment to see what kind of performance emerged.

 

This would mean removing the worms on the dead motor. It proved impossible to get them off. A really tight fit on the shafts and no room to get sufficient support between the back of the worms and the motor body to tap them off with a drift. Since the motor was dead I eventually got a diamond needle file in the gaps and cut the shafts off, then being able to tap the remaining sections out of the bores.

 

 

At this stage I discovered a few things. Firstly, on stripping down the motor I found it was well made, decent commutator brushes and with a large 5-pole skewed armature. The magnets are very strong but why it cogged so badly I still can’t work out nor why it needed a feedback controller to run slowly on DC, because it shouldn’t have given the spec. Nor could I find any reason why it had failed. Hm.

 

 

Then I noticed something else that I’d missed before. The gears in the motor bogie are large tooth, roughly 42dp, and with 16 tooth spur gears. I had thus assumed the gearing was 16-1, okay for a diesel with small wheels although a higher ratio would have been better for slow running. However I was wrong, because I had missed that the brass worms were two start and not the normal and common single start worms that are used. So the gearing was actually only 8-1. Jeez, quite ridiculous. This kind of gearing ratio was quite common in days of yore with large and heavy current draw slow running motors but a bit silly now. This helped explain the often coggy, jerky, slow speed running I’d got and I was very glad I had not got another railroad motor/gears combination to replace the failed one.

 

So, what now? Well, if I could find some single start worms to go with a Mitsumi motor I might have a solution. As luck would have it I did have some suitable worms, from a distant time when I produced worm gear sets for O gauge in a couple of different sizes, 42dp and 50dp.

 

With a couple of 42dp worms on the shafts the Mitsumi motor fitted nicely into the space and plasticard was used to place the motor in the correct position for meshing with the spur gears.

 

 

 

Once it was all wired up I found the performance far, far better. Decent slow speed running with the simplest DC controller. Had I tried this motor conversion before obtaining the full fat model I most probably wouldn’t have bothered. It just never occurred to me but would have if I had spotted the low 8-1 gear reduction which would have set alarm bells ringing.

 

 

So that’s the loco back up and running nicely but it is still now surplus to requirements so perhaps I will again try selling it.

 

Bob

 

[Izzy]

J15 with two speakers

 

Well, it's been a while since I last posted on this thread. It isn't that things haven't happened, All Saints East itself has been completely rebuild for a start, and new items in the form of a couple more locos added, but the main focus has been elsewhere with another scale/gauge.

 

However the making of these new locos and fitting them with sound, (a J68 from an etched kit and a Thompson L1 using a Hornby body on an etched chassis), brought to my attention that the only tender loco, the converted Hornby RTR J15, didn't sound right with the sound clearly coming from the tender and not the loco. This wasn't readily apparent when I first fitted sound to it after the conversion to P4 but slowly became apparent over time when run alongside the other locos.

 

The question was, what to do about it? I'm afraid I am one of those people that can't leave things as they are if I find something that's not right and isn't to my liking. There was nothing wrong with the sound, the J15 project from Youchoos, indeed it sounded great (and stills does) with a few tweaks for personal preference for individual sounds levels.

 

Now I'd fitted sound to both these new steam locos by fitting speakers into their smokeboxes and it began to occur to me that this was what I needed to do with the J15. With a speaker already in the tender and having read and posted questions about twin 8ohm speaker set-ups it seemed quite possible to do and especially as I had fitted a Zimo MX645 which can cope with this in either speaker wiring formation of series or parallel, having a 4-8ohms output. Speakers wired in parallel halve the impedence while in series this doubles. So two 8ohm in parallel are 4ohm while in series it becomes 16ohm. It seems the lower the impedance the louder they are and visa versa. The speaker impedance must obviously match or be less than what the decoder can provide. So in parallel is not possible for those that can only provide 8ohms, which is the vast majority of Zimos. ESUs are all 4ohm I believe.

 

The big issue was finding the space. The Hornby J15 has a cast metal footplate and upper body in two halves for weight which is great but what space remains is stuffed with the chassis and motor etc. There is no empty space at all. Eventually after measuring it all up I realised I could, just, squeeze one of the small 15×11mm planar speakers I have used recently into the smokebox standing vertically, but only if I was able to cut out the large chunk of metal that sits there behind the smokebox door.

 

 

It took me quite some while to pluck up the courage to attempt this, the ever present danger of just wreaking the complete loco not being far from my mind. Because finding a spare body would not be easy (probably impossible) should things go pear-shaped. Trying to work out how to actually cut out this metal section also took some time. If only the smokebox door came out…..and I could get the boiler/cab off the footplate….

 

In the end one day I just took the plunge, parted the loco and tender, and took the body off the chassis. After removing the screws under the cab floor I managed to slowly lift the cab away and by gently levering the cab/boiler up/down it started coming away from the footplate. It took a long time as I didn’t want to bend/warp/crack the footplate. The front slips under the footplate and this is what the chassis screw goes into. It was the middle part of this tall square pillar I had to remove, well almost all of it actually except the very bottom bit with the screw hole.

 

As there was a gap either side which shows the rear of the smokebox door I decided to push my luck and see if I could force the door out from the rear. I guessed it was glued into place. It’s plastic, one of the few parts that are. Just when I was about to give up it flew out of the front with a crack and ended up on the floor feet away. Given the sound made I thought perhaps I’d smashed it, but no it was intact and undamaged. That was lucky!

 

 

 

 

With it removed there was then easy access to the pillar and so I chain drilled it top and bottom to remove the bulk and cut it out and then spent a long time cleaning it all up with burrs in a mini drill and to get the square corner shape into which the speaker would fit. I had to cut away the pillar below the front of the smokebox which was a tricky task to complete.

 

 

 

Once done it proved possible to get the speaker into the space but only a flat piece of plasticard could be added onto it to make a sealed enclosure.

 

 

 

After soldering on the wires I wrapped it in Tamiya masking tape for insulation against the body, not wanting electrical shorts of any kind. This tape was also used to hold the wire runs to the inside of the boiler.

 

 

Initially when all done and wired up I found the larger Zimo speaker in the tender still overwhelmed the other volume wise, so replaced it with another 15×11 planar to get an even sound output. This worked nicely. Now it seems as if the sounds come from the loco itself whichever direction you listen from. So a lot of hard work but worth the effort.

 

Bob

Edited February 7 by Izzy