Monday, July 16, 2018

Track Power

When it comes to making working models getting the pickups right is really important; no pickups means no power which means the loco doesn't move. Unfortunately I always seem to struggle with pickups be that on a kit I've bought or one I've designed. As I mentioned previously, with Canopus I only have to fit pickups to one side as the chassis is live to the other wheels (a change from the original kit design) but that still means I need to fit three pickups. There is a suggestion in the instructions but no mounting point, you are just given a bit of copper clad board and some wire. After a bit of head scratching this is what I came up with.


What you can't see is that I've filed a gap in the underside of the board so it sits down nice and secure on the stretcher between the slide bars. This made it easy to position and glue in place. Phosphor bronze wires then run from the board to rub on each wheel. Amazingly it all seems to actually work. I did have to clean the wheels well, but given the amount of handling the chassis has had since I started the build that's not entirely surprising. Anyway here she is running for the first time under track power.


Not bad if I do say so myself. As far as I can tell the loco is now complete so next step will be to start thinking about a paint scheme.

Friday, July 13, 2018

Short Circuit

Short Circuit was a great 1980s film that I quite enjoyed as a kid (not my favourite 1980s film but not bad all the same), but when it comes to railway modelling the last thing you want is a short circuit; it's more likely to end in tears and you pulling your hair out rather than laughing hilariously. Now imagine my surprise that I've had to solve a short circuit issue on Canopus.

In fairness I think this issue is down to the original wheels the kit was designed for not being available when I bought mine and so a different set were provided. Originally both wheels were isolated from the axle. This means that you had to fit pickups to the wheels on both sides of the model, but that the model itself was insulated from the track. The replacement axles have only one wheel isolated and the other is live to the axle. This means that I only have to fit pickups to the isolated wheels as I can just connect the motor direct to the chassis as the power will flow from the wheels to the axle, through the bearings and into the chassis. So far so good; I hate fixing and adjusting pickups so I'm more than happy to halve the work involved.

The problem though is the trailing wheel. If you remember from a couple of posts back the wheel is mounted on a metal truck that pivots from the chassis. Now while both wheels are isolated from the axle, there is enough movement to allow the wheels to both touch the chassis and for the back of each wheel to touch the pony truck. If this were to happen to the wheel on the same side as the insulated driving wheels we'd have a short as both rails would now be connected to the chassis.


My solution to this involves two modifications. The easiest bit was to ensure that the wheel couldn't short against the chassis frames. I've fixed this by putting a piece of masking tape on the inside of the frame. To try and make sure it doesn't come off I've run a small bead of superglue around the edges and then painted it black to hide it against the frame (it's unpainted in the photo). Making sure the wheel can't short against the pony truck was harder. I went through a number of ideas for this but in the end I thinned the truck slightly and then glued a thin piece of plastic to the side (so that with the plastic the truck is still the right width).

As far as I can tell these two modifications should ensure that the wheel now can't cause a short circuit, but the real test will of course come when I finally wire up the pickups and test the loco on the track. Fingers crossed.....

Tuesday, July 10, 2018

Cylinder Drain Cocks

Whilst I may have finished most of the build of Canopus there are still a few detailed bits and pieces to work on. One issue with replacing the cylinders was that the front face didn't have any of the detail of the cast parts. I did contempate etching some covers with rivet detail, but in the end decided it would be easier to use up some scrap wire and tiny brass washers and model the cylinder drain cocks which were quite a prominent feature on the prototype.


As you can see these things are tiny and took four or five different attempts until I managed to produce something I was reasonably happy with. Each is made from two pieces of 0.45mm wire slid through a tiny brass washer (I bought the washers to fit on the crank pins). One of the wires had two 90 degree bends put in it to form the tap handle. Everything was then soldered solid nicely forming the body of the tap. The wires were all then trimmed back and the spout gently formed before being glued to the front of the cylinders.


Compared to photos of the original loco they are a little over scale, but given how tiny the parts are I'm not sure I could sensibly make them any smaller. Once everything is painted they should also be a little less obvious, and if necessary I can file the spout and handle back a little more.

Monday, July 9, 2018

Cutting Up A Pony

Next up in the continuing saga that is the process of building Canopus is the rear pony truck -- the original loco had a fixed trailing wheel but it pivots in the kit to help the model negotiate tighter curves. The part is supposed to be built from a simple fold up etch but the instructions go on to state that...

as supplied the bogie frame is for 10mm gauge. For 009 it will be necessary to snap off the fold-up sides of the bogie and refit them 0.5mm inboard of their original positions.
Quite why this part is designed for 10mm gauge when the rest of the kit is designed for a gauge of 9mm is simply beyond me. However, the idea that I could snap off and accurately reattach the parts just 0.5mm inboard was also a bit of a joke so I opted for a different approach.

I found a piece of brass tube with almost the same hole diameter as on the etch (the tube has a slightly wider hole) but with an outer diameter which when rested on the folded up part aligns perfectly with the axle holes. So I folded up the original etch, cut a piece of the tube to the correct size, and then held it in place for soldering using a piece of rod slotted through the original 10mm gauge axle holes and the tubing. The original sides were then simply snapped off and the sides cleaned up and filled back to narrow the truck to the same width as the tube. This was then riveted to the stretcher that will be attached to the chassis frames.


The sharp eyed amongst you may also notice that I've filled away part of the stretched just off centre. Whilst it did just fit, there was practically no daylight between the stretcher and the larger of the gears in the gear box. Even now with that section filed back there isn't exactly a lot of clearance. I'm not sure if this is yet another design issue or if it's related to the change in gears from the original kit, either way it could easily catch out the unwary.


You'll possibly also notice that clearance between the stretcher and the worm gear is also fairly minimal. I've actually reduced the length of the worm quite a bit, having now removed about one and a half turns of the gear from both ends; from one end to clear the fixing screws for the motor/gearbox and from the other end to clear the pony truck stretcher. Fortunately there is still plenty of worm gear to mesh cleanly with the large gear in the gearbox.

Amazingly, baring fitting the pickups, that's the last step of the instructions finished!

Friday, July 6, 2018

Powered Waggly Bits

So having fixed the cylinders to Canopus it was clear that the clearances were minimal behind the crossheads. Slowly turning the motor over by hand and everything seemed okay, although on one side it did look as if the crosshead was pushing on the retaining nut on the front flycrank. Under power everything did move but it was very jerky as the two parts rubbed against each other.

On closer inspection it turns out that when I widened the slidebars I didn't refit them completely central, so while one side was very tight for clearances there was quite a lot of space on the other side. So I've now removed the cylinders and slidebars, refitted the slidebars more centrally and then refitted the cylinders. Although the clearances are still tight I can now see daylight between the parts all through a full rotation of the wheels. More importantly under power it seems to run quite nicely.


Next up is the pony truck, which unsurprisingly will need modifying before it can be fitted, but more on that next time.

Thursday, June 28, 2018

A Blast From The Past

Having finished the Clayton commission I decided I'd try and finish some of my stalled projects before starting anything new. First up on the workbench is my build of Backwoods Miniatures Canopus. Last time this appeared on the blog was November of 2015, when I was in the middle of trying to fix all the issues with the parts supplied with the kit; on that occasion the slidebars being two narrow. While problems still remain the model is really quite close to being finished, and so I'm going to make a determined effort to see it through to completion.

After altering the slidebars and riveting the connecting rods to the crossheads, the next step in the instructions is to fit the cylinders. Not entirely surprising but it turned out not to be as simple a task as it sounds. In theory all I needed to do was drill a 0.8mm hole through each of the two whitemetal castings for the piston rods to slide through. I drilled the first cylinder with no problems at all, but drilling the second one seemed impossible. Not only did I break a drill bit but even when I'd found a second drill I just couldn't get it to drill through. I'm guessing an impurity of some form in the casting. Either way this left me with only one usable cylinder, so I decided to turn up a replacement. Fortunately I checked the one good casting against the loco before starting as in the end I had to turn up a pair of cylinders.

The instructions suggest that the cylinder should have two notches on one end into which the slidebars fit into. My castings didn't and worse still when the cylinder is held in place against it's bracket the slidebars are almost a millimetre too short to meet the face of the cylinder. So my turned replacements are the same diameter as the cast parts but about 1mm longer so that they fit in the bracket and against the slidebars.



While the cylinders are now a bit longer than they should be I don't think they look too out of place on the loco. Even having moved the slidebars outwards (back in 2015) the clearances are still really tight but turning the motor by hand seems to suggest there is enough space for everything to move past each other.... just. The test will be when I find where I've put the rolling road so I can give it a powered test where I can watch everything closely.

Thursday, June 21, 2018

Clayton #5843 in Ex-Works Conditon

It's been three years since I first started work on a model of Clayton #5843, and in that time I've worked on three different models. The first had issues around the print bending and was never finished. The second was built for running on Rhyd but balance issues meant the heavy pewter driver figure caused the loco to kangaroo along the track, so he had to be replaced by a plastic figure. I've now finally finished the third iteration of the model (another commission so I've still not built one for myself) that includes more weight and finally allows the nice pewter figure from Andrew C Stadden to take it's place in the "cab".

It's new owner has requested it in ex-works condition (so they can have it weathered to match existing stock) and so here it is fresh from the paint shop.


While it would benefit from a little more running in (difficult on my short O14 test track) it's running a lot smoother than previous versions with the driver figure on board and is showing no sign of bouncing along the track.


Now I really should get another set of parts together and build one for myself, but first I'll need to take a trip to the post office to get this one on the way to its new home.

And Smaller We Go...

A couple of posts back I talked about converting the KATO 11-107 to a tiny 4 wheel chassis in the hope it would be small enough to fit a model I'm working on. Turns out that although it's small it's not small enough, not by quite a long way, so I've had to have another look at power options. The result is that I'm trying another well made KATO power unit but this time taken from one of their Centram models.



Not only is the tram model tiny (it's N gauge after all so a scale of 2mm to the foot) but it's been modelled so as to leave the inside empty so you can add your own passengers. This means that all the drive components are hidden under the floor. In fact the model contains two completely independent power bogies which when removed look like this.


Each wheel is just 4mm in diameter which gives you some idea of just how small and compact these are. The circuit boards drive the lights as well as reducing the track voltage to protect the tiny motor, and can be replaced by a simple resistor if you want to make things even more compact.

The problem though, is that when removed from the model there is no connection between the pickups and the circuit board and motor meaning they don't work. The tops of the pickups are the rounded brass pieces sticking up on either side between the wheels. When assembled into the Centram these rub on phosphor bronze strips which connect the pickups to the circuit board which in turn powers the motor.

Now most people solve this problem by soldering wires to the pickups, but you have to be fast. Not only are the pickups touching the plastic casing, but inside the chassis a set of plastic gears run alongside each pickup and they are easily melted if you get the pickups too hot. While you might get two chassis from one model, the model still costs between £80 and £90 (you have to shop around but this is a common price; I got mine cheaper by buying a second hand "as new" model) and so you don't want to destroy a £45 chassis by lingering too long with the soldering iron.

My solution was to design a small clip (which you saw in the earlier post balanced on a 5p coin) which could retain two pieces of phosphor bronze rod which would in turn rest upon the pickups.


It's not the most innovative piece of design work ever but it does the job. The slots for the rod to fit in are slightly undersized, to ensure a tight hold, and directly inline with the pickups so that the rod has to flex slightly ensuring a good push against the pickups. It means that all the soldering can be done away from the chassis and then the rods just clipped in place, and can be easily dismantled again if need be.


You could cut the wires on the chassis and solder them directly to the rods (via a resistor) but I'm going to retain the circuit board for now to use the lighting circuit so I've just soldered on loose wires to prove the system works, which were then wrapped around the terminals on the circuit board. The nice thing is that it opens up using the chassis for anyone who owns a soldering iron no matter how bad their soldering is, without any chance of damaging the chassis, so I'd call that a success even if, as I said before, the design isn't going to win any awards.

Tuesday, June 19, 2018

Test Print

A Shapeways order arrived today so I can restock a number of Narrow Planet kits, but it also included a test print....


I'll explain in a later post, but anyone want to take a guess?

Saturday, June 9, 2018

Power Options

While I've not had lots of time for modelling recently I've been pondering a number of locos that, given the time, I would like to model. As with a lot of the other locos I've modelled in the past these tend to be quite small engines leaving me with few, if any, options for powering them. When I hit this problem with the Hudson Hunslet 24hp diesel I ended up designing a custom chassis for it, and I might still take this route, but in the interim I've been looking to see what existing chassis I might be able to adapt.

The KATO chassis from Japan have a good reputation for reliability even if they can run a bit fast; I've used one in the past when I built my first OO9 loco. Most of their chassis are, however, quite a bit bigger than I'm currently looking for. Or at least that was what I thought until I read a short article by Roger Lycett-Smith in issue 263 of Model Railway Journal (MRJ).

Roger had built a model of a tiny open-cab 4 wheeled Ruston using a KATO 11-107 chassis which starts out looking like this.


Clearly as it arrives, it's not going to be much use for building a 4 wheeled loco. It turns out though, that inside the white casing the motor sits above one of the bogies (which isn't driven) and is connected via shaft and universal joints to the gear train on the other bogie. What Roger had done was to rearrange this setup so that the motor was directly connected to the gear train. My attempt at replicating this resulted in...


Having now done this myself, I've discovered that the instructions in MRJ don't quite make sense. Roger states that...

The power bogie, worm removed from it's carrier and fitted direct to motor shaft, which has been slightly shortened and a brass strip made to secure the motor to the bogie
Unfortunately the shaft on the motor is no where near long enough to pass through the worm, and certainly not long enough to need shortening. In fact if you only attach the worm to the motor shaft it wobbles around quite loose in the housing; this might be partly due to me not having permanently fixed the motor in place but even so I would imagine it might lead to unnecessary wear of the gears if they are moving around too much. My solution, has been to fix the worm to the motor shaft and then insert the original pin the worm was on from the other end. This means the worm is now supported at both ends as before. It also means I have a rotating shaft onto which I'm wondering if I could fit a small flywheel; a job for the lathe next time I have enough desk space to turn it on.

I've not soldered wires onto the pickups yet as I'm considering some more radical butchering to fit the loco I want to model, but I have tested that it runs nicely like this by attaching power direct to the motor terminals.

While it's certainly not the smallest chassis, it has the advantage of being made from reasonably high quality parts which are known to be reliable, and it uses a proper 12v motor. Plus the chassis are cheap; you can buy them in the UK for about £24, although if you are happy to wait you can get them direct from Japan for around £14.

Sunday, March 18, 2018

As Seen In...

Some of you may remember that back in December I completed the I P Engineering kit of a 16mm scale Hudson Skip locomotive. At the time I didn't go into too many details about how I'd built and detailed the kit, this wasn't for any good reason, other than I'd not written anything down. Well now I have and the results are a four page article in the April issue of Garden Rail magazine.

One of the people who read the original post was Phil Parker (if you don't already read his blog then you should) who suggested the editor of Garden Rail would like an article on building such a kit, and he should know given he's the editor of Garden Rail! So over the Christmas holiday I put together a quite detailed article on the build and all the extra detailing, including how I built a rivet press. So if you want the gory details go buy a copy.

Buying a copy of this article is much easier than all the previous articles I've ever written (either railway related or work related) as Garden Rail is sold on the high street so, for example, you can walk into your local WHSmith and pick up a copy. I got sent a copy, but I might even go buy an extra copy just for the thrill of it.

Friday, February 23, 2018

Gunpowder

After dipping my toes into modelling in OO6.5 gauge I decided to see if there was anything a bit more interesting I could model, that might also be usable in OO9 gauge. I didn't have to look far as the Royal Arsenal Railway had an interesting little gunpowder van, which sat on a very similar chassis to the transfer wagon. Mark Smither's book on the railway contains a couple of small photos and a drawing (although I discoverd that the drawing is wrong in a couple of important ways) and I managed to find a few photos of a surviving example which is now at the Conway Valley Railway Museum. Putting these together with the existing chassis model I managed to produce what I think is a really nice little model. First in OO6.5 gauge...


...and also in OO9 gauge.


Design wise the model is a bit of a departure from previous wagons I've designed as in the end I opted for a mixture of 3D printing and etched metal parts. The reason for this is that with the external framing there is no orientation you could print the model in that wouldn't result in support wax covering all the planks, which would likely result in a horrible surface and the plank gaps being obliterated.


The combination of 3D printing and etched parts works really well together on models like this and I'll certainly take this approach again on any similar models in the future.

There are a few issues to finalise but hopefully it shouldn't be long before complete kits for both the OO6.5 and the OO9 gauge versions are available via Narrow Planet, price yet to be confirmed but I'm sure I'll do another post when they do appear.

Friday, February 9, 2018

Stop Blocks

Having previously produced models of the chimneys and finials used on some of the stations on the Lynton and Barnstaple Railway I've now been asked by the same people to look at another set of detailing items; the concrete and wooden stop blocks. While it turns out that they changed quite a lot over the years and no two appear to be exactly alike, research (mostly carried out by Chris Harvey) suggests that there were a few basic versions. Each block consists of a concrete post, some of which have a sloping back, and a wood block which could be either wide or narrow. From those details I've worked up a set of test prints that when painted look like this.


I had to take four separate photos as each stop block is actually made up of two parts that fit together and I only test printed one of each part. Essentially the wooden block has a peg on the back that slides into a slot on the front of the concrete block.


As you can see I've also made it so that an hex nut can be slotted into the concrete part, which not only allows you to use a bolt to secure the two pieces together (not needed really as the parts are a nice tight push fit) but to also bolt the buffer to the baseboard so that it might actual withstand the force of a train colliding with it; the bolt is made from nylon to make it easy to cut to length.

The height of the blocks was carefully chosen to allow them to be used in two different ways. For those who model the L&B and want the block to be the correct prototypical height then they can be mounted on top of the sleepers. If, however, you mount them direct to the baseboard (so the bottom of the block is inline vertically with the bottom of Peco 009 track) then the loop on a standard 009 coupling should just slide over the top of the block with the face of the coupling aligning with the wooden block.

Whilst these were designed at the request of a number of L&B modellers, hopefully they will be of interest to other 009 modellers. A a kit will consist of both a wide and narrow wooden block, a nut and bolt, and either a square or sloped back concrete part (you'll be able to choose which style you want when ordering). I need to order stock before they go on sale but a single kit will be £7 or we can offer a pack of 3 kits for £18.

Tuesday, January 30, 2018

Finally, Some Movement

Having spent some time over the weekend when the little one was asleep doing some work, I managed in return to get a little noisy modelling done yesterday while he was at nursery; I do love having a job that allows me flexibility in when I work as long as the work gets done. The result is that I've managed to move the Clayton O14 loco build along a little to the point where it's now moving under track power.


The downside of more weight is that there is even less space inside than before so I had quite a few problems with electrical shorts, but after some careful tidying and some electrical tape in key areas it moves. Clearly the wiring is just temporary; there isn't room in the loco for all that spare wire but I've left everything nice and long until I sort out the lights and will wire everything up properly in one go at the end. The pickups possibly also need a tweak here and there to improve running, but I'll probably do this once the model is painted as they'll only get knocked when the wheels are dropped out etc. The good news is that with the extra weight introduced in this version it seems to run nicely, although I'll only know for certain how it performs once I try adding the rather heavy driver figure as that was what caused the most problems last time. For now I'm happy with how it's coming along though.

Whilst assembling the model I did briefly ponder another change from the previous version. I managed to accidentally assemble the model without fitting axle bearings. The result, as you can see in the video, was that the wheels were free to rotate slightly around the centre line of the locomotive.


Many models are actually designed to incorporate features similar to this, usually refereed to as a compensated chassis, to help the wheels maintain contact with the track at all times, and hence to ensure proper power collection over points etc. While I did briefly ponder leaving the model like this I decided not to, simply as I was worried that the plastic gear would suffer terrible wear against the stainless steel keeper plate, but has anyone done anything like this before? Any thoughts on how successful or terrible an idea it is?