Tuesday, August 14, 2018

Insulated Driving Wheels: An Experiment

While the build of Ivor might be on hiatus, I now have four wheels which are effectively scrap (given that they are no no longer the same size) on which it is safe to experiment. The final two pieces of the wheel design I needed to finalise were the insulation from the axle and the crank pin.


Let's start with the insulation first. It's difficult to see in the photos but what I've done is to simply take the test axle from a few posts back and fit this to one of the wheels. This involved opening out the axle hole in the wheel to 2.8mm which is a nice tight fit for the insulating bush I took from a pair of hornby disc wheels. I'm not sure this is the final way I'll go (I might try turning my own insulating bushes) but it is nice and straightforward and seems to adequately insulate the wheels from the axle at little effort or expense. Obviously on the real wheel I'd trim the axle back to the face of the wheel.

When I was originally working on the 3D model for the wheels my plan was to use a 14BA screw as the crankpin with a hole through the wheel tapped for 14BA so the screw would actually screw into the wheel. I had wanted to cast a recess into the back of the wheel to seat the cheesehead bolt but the wall thickness requirements meant that wasn't possible. So my plan was to screw the bolt into the wheel and then cut the head flush with the back. A little drop of loctite helping to hold the bolt in place. Unfortunately while I managed to open out the hole big enough to tap, I then broke one of my 14BA taps and stripped the cutting threads from another. With no taps left I opened the hole up slightly further so that the bolt was a tight sliding fit. Rather than holding it in place just with loctite on the body of the bolt I decided to drill a recess for the bolt head anyway as there seemed to be enough material. With that done the bolt sits nicely in the back of the wheel and the bolt head helps to keep the bolt perpendicular to the wheel while also providing more surface area for loctite to hold it in place. Once the loctite had set I did try pushing the crankpin out and couldn't do it by hand. Even with a set of pliers it took a lot of force to break the seal, so this definitely looks like a workable solution.

Friday, August 10, 2018

Ivor is Going on Hiatus

So unfortunately work on Ivor is going on indefinite hiatus.

After doing the maths this morning I thought I'd go ahead and turn the wheels down to 20mm from their original 21mm diameter. If you remember when I originally turned the wheels I said it was hard work to get them down to 21mm, well getting down to 20mm seemed nigh on impossible. I continued to take it very very slowly but the work involved looked like being too much for my lathe without substantial extra work to the wheel (thinning the depth and reducing the width with a normal cutting tool first etc.) but with perseverance I got the first wheel to 20.5mm and so decided to split the difference and stop there. All (reasonably) good so far.

Having let the wheel cool (they get quite hot during profiling) I went to undo the wheel holding fixture only to find it was quite tight. I gently used a pair of pliers to start loosening it (I did this last time when it was too hot to touch) only for the threaded rod to snap in half! This means that the wheel holding fixture is now useless. More to the point I now have one 20.5mm diameter wheel and three 21mm diameter wheels so Ivor is going nowhere anytime soon.

I think the best thing to do is simply put the kit away for a while and focus on something else. This will give me time to rethink the wheels (I'll redo the 3D model for a smaller diameter and to make them easier to profile) and probably to save up to replace the wheel holding fixture. I could continue on with the body, but I think I'd just get frustrated knowing I couldn't fit it to a working chassis (plus it might need modifying to fit the gearbox etc.) so will probably turn to something else entirely. Not sure what yet, but I'll be sure to post when I've done something new.

Determining the Wheel Diameter

I've been having a bit more of a think about the wheels for Ivor after yesterdays discovery that they are probably too big to both fit inside the splashers and next to each other. It's also been pointed out to me that, normally the centre line of the buffer on standard gauge stock sits 3' 6" above rail height, which would be 14mm in 4mm to the foot scale. While Ivor isn't exactly based on a real loco, it would still be useful to have him sit at roughly the right height if I don't want him to look daft against standard 4mm wagon kits etc. The upshot of this is that I've been doing some maths...


The upshot of all that is summarised in the bottom right hand corner. My original 21mm diameter wheels would put the centre line of the buffer at 14.5875mm above rail head, so about 0.6mm (or almost 2" in real life) too high. To get it to sit at exactly 14mm I need the wheels to be 19.825mm in diameter (excluding the flanges).

I think given this bit of maths (and if anyone fancies checking my working it would be most appreciated) that I would be better off reducing the wheels to 20mm (or 5' in real life rather than the suggested 5'3") which would give a total diameter including the flange of 21.27mm which given the wheelbase of 22.5mm should leave a gap of 1.23mm between the flanges of the two wheels.

Does that seem sensible to everyone?

Thursday, August 9, 2018

Is It Just Me?

I'm beginning to wonder if either I'm drawn to kits with design issues, or if I'm just not very good at building kits accurately.

Having finally battled all that was weird and wonderful with the Canopus kit I thought the kit for Ivor the Engine looked quite a bit easier. Okay I made life more complex for myself by deciding to make my own wheels, but in itself that shouldn't affect the design of the kit. Having built up the chassis (fairly easily I may add) I've now made a start on the body, which in turn has led me to discover a couple of, potentially, catastrophic issues.


So far I've formed the splashers and attached them to the footplate, which also includes the front buffer beam. What you can see, in the photo above, is the chassis slotted into the footplate containing one of my wheels on the test axle I turned.

The first problem was that the chassis wouldn't fit into the footplate as it was slightly two long. After a lot of careful filing I've made it fit and the fixing holes appear to line up pretty well. The second problem though is that the chassis wouldn't fit with the wheels attached. In the photos you can see that I've bent the front of the splashers that are inside the model to get the wheel to fit, and it still feels like it's catching when I turn the wheel. I think the solution to this will be to cut away the extra metal, as it can't be seen once the model is assembled, and isn't needed to keep the chassis central once the screws are in place. Before doing that though I wanted to figure out why the wheels didn't fit.

Looking again at the instructions, which are just a sequence of photos with no textual description, I think all the photos show the 7mm version of the kit and not the 4mm version. It's difficult to be sure as most of the photos don't include anything to give a sense of scale, but they all seem to have previously appeared in this RMWeb thread discussing the build of the 7mm kit. The one page that is clearly for 4mm gives the size of the finished model and is the place where it suggests to use Ultrscale OR Markits 5'3" 16 spoke wheels with 8 spokes removed. As I was making my own wheels I took the 5'3" as a starting point and produced 21mm wheels (5.25*4). As I made the wheels to RP25-110 the flange depth is 0.025" or 0.635 giving a total wheel diameter of 22.27mm. The instruction page also states that the wheelbase is 22.50mm which as far as I'm concerned is just a bit too close to 22.27mm for comfort. In fact placing two wheels against the chassis I'm not sure they will fit without the flanges touching!

Reading through the thread on RMWeb I did notice that the suggested wheels in 7mm scale are actually 5'2" diameter not 5'3". I know that would only change their diameter by a small amount (they would be 21.94mm over the flanges) but that extra clearance would probably be great for both the splashers and between the wheels.

I can't be sure that the flanges will touch until I turn up a second axle (I've just the test axle so far) but if they do then I guess I'm going to have to try and reduce them in size slightly which is a real pain, although it might mean I can remove the slight flats on the flange from removing the wheels from the sprue. Mind you that isn't really the point; if I'm following the instructions for a kit am I just picking kits with issues, or am I just not assembling them accurately enough?

Monday, August 6, 2018

RP25-110

Next up in the sage of making wheels for Ivor is the bit I've been dreading the most; profiling the wheels to add the flange. In theory this should be easy as in essence all it involves is reducing the diameter of the casting using a profiling tool, but that glosses over a whole bunch of issues.

Let's start by defining exactly what we mean by "to profile" a wheel. Put simply it's to shape the tread and flange of the wheel to a specific shape. There are lots of different profiles all defined by different guidelines and associations. For Ivor I've settled on using wheels profiled to match RP25-110. This means I'm using the RP25 profile, as defined by the NMRA, with code 110 wheels, i.e. wheels that are 0.110" in depth (or for those who prefer metric, 2.794mm). Now a lot of the work of making the wheels fit this profile was done during the design of the 3D model as it set the depth etc. but it is impossible to 3D print thin enough and accurately enough to produce the flange.

To add the flange (and to ensure a nice smooth turned tread) I'm going to finish the wheel profile on the lathe, using a specific profiling tool. You can get profiling tools from numerous places but I picked up this one from Carbide Solutions as it had a square shank which made mounting it in the lathe easy.

Even with a sharp profiling tool (I'd not used mine before) this is actually quite hard work for the lathe and involved taking very very tiny cuts and quite a few breaks even during each wheel to ensure I didn't over heat the lathe or the wheel (it got exceptionally hot).


As you can see I've held the wheel in the lathe using a tool designed specifically for the job (another purchase from fohrmann-WERKSEUGE). The tool ensures the wheel is perpendicular to the lathe bed and clamped tight, although I did manage to over tighten the clamp on two out of the four wheels which unfortunately opened out the axle hole in the wheels slightly -- not a problem as I'll fit insulating bushes to these two wheels so will need to open the hole further anyway.

You'll also notice that I've left as little of the profiling tool hanging out of the toolpost as possible to try and reduce chatter, and I clamped the crossslide tight so as to remove as many sources of movement as possible. On the first wheel I started with the lathe on a slow speed but that was a disaster as the tool tended to dig in and bounce around, even with the lathe locked as solid as possible. I reconfigured the belts to run the lathe on it's fastest setting (4000 rpm) and with very very tiny cuts this worked a lot better, and fortunately I figured this out before destroying the first wheel. Once I'd reduced the first wheel to the correct diameter (21mm for 5' 3" wheels at 4mm to the foot) I took a note of the position on the cross slide, and then repeated the process for the other three wheels.


It took me all morning (in blocks of a couple of minutes here and there) but I've managed to profile all four wheels. While I'm not going to claim any of the four as perfect, I'm happy enough with them all to try and assemble the loco. All four have a difference of no more than 0.02mm when measured and all are slightly above 21mm rather than below, so they are close enough that I think they should sit level. The main issue with them is that when I removed them from the sprue, and filed the excess away, I didn't take into account that the edge of the flange was the edge of the casting (something I'll change if I produce any more) and so in a couple of places there is a slight straight edge on the flange, but hopefully not enough to cause a problem, if it is I can always order another set and replace them but fingers crossed...

Friday, August 3, 2018

Axle Hole

Having separated all four wheels for Ivor from the sprue they were attached to during printing the first step is to drill out the central hole to take the axle. Normally if I was trying to make a hole to fit an axle I'd drill it slightly undersize and then open it out slowly with a reamer to get a tight push fit. In this case though I'm going to turn the axle as well, so I can make the axle fit the hole. This means I can use a cheap drill to make the hole and not have to worry about buying an expensive reamer. That isn't to say this step doesn't include expensive tools as not only did I do the drilling using my lathe but I bought a set of step chucks specifically for the task.


Specifically I bought the 20.00mm to 24.50mm step chucks from fohrmann-WERKZEUGE. As you can see these allow me to hold the wheel (or any other appropriately sized cylindrical object) in the lathe for accurate centre drilling. In this case I've used them to widen out the axle hole to 2mm in each of the four wheels.


Visually the wheels all look good and the hole appears to be nice and central so hopefully that's the first step successfully achieved, and now they all have an identical sized axle hole I should be able to mount each in turn in the same position in the lathe which should make turning the flanges on each in turn a little easier.

Thursday, August 2, 2018

Flangeless Wheels

Having checked that I could machine the silver steel rod to make axles I've turned my attention to the actual wheels. I've actually been working on these for a while now. The main problem I had is... what do Ivor's wheels look like? While they always seem to have the same number of spokes they seem to differ slightly from scene to scene, mostly around the thickness of spokes. However, in some shots the wheels have balance weights and in some they don't. In the end I decided to work from a specific drawing in my childhood book.


The plan was to make a 3D model of the wheel, bulked out in diameter slightly. These would then be printed in brass, and then finished on the lathe using a profiling tool. So far I've designed the model (see above), had them printed as a sprue of four wheels (cheaper than printing each separately) and separated the wheels from the sprue.


Next up will be drilling out the central hole for the axle and using a profiling tool to reduce the diameter slightly and add the flange.

Stepped Axles

Having assembled the basic chassis the next step is to figure out the wheels. Unfortunately as the prototype is a cartoon character there aren't any wheel sets I can just buy off the shelf. The only suggestion in the instructions is to use "Ultrascale or Markits 5'3" 16 spoke wheels with 8 spokes removed". Having looked at both of these options I wasn't happy with either, as even with the extra spokes removed I didn't think they really matched up with those you see in the cartoons. In the end the only thing I could think of was to make my own wheels. Clearly this isn't going to be a quick and simple process so it's likely to go on for quit a few posts as I detail the different steps and experiments. In this post I'm going to concentrate on the axles.

As I mentioned previously the kit is designed for use with axles with a diameter of 1/8". The wheels on Ivor don't have a huge central boss, and certainly not something big enough to accommodate a 1/8" (or bigger for an insulating bush) hole so my plan is to use stepped axles. Most wheels seems to use steel for axles so I've bought some 1/8" diameter silver steel rod (from Eileens Emporium) but having never tried to turn anything other than soft brass rod (CZ121 brass to be precise) I had no idea how well this would work.


For a quick experiment I've turned down a short length of the silver steel rod to take one of the OO gauge wheels I used to build the Clayton. These wheels fitted on a 2mm axle so I had to remove roughly 1.25mm from the diameter of the rod. I actually found machining the silver steel possibly easier than brass and the turnings come off as long thing ribbons rather than lots of dust. All told (including setting up the lathe) this took about 10 minutes. Now obviously machining steps on both ends of an axle and getting the back-to-back correct is going to be more time consuming but at least now I know I can work with the materials I've got, and I've 26" of rod (minus the short test piece) to play with and I only need two short (approximately 19mm) axles.

Wednesday, August 1, 2018

In the Top-Left Hand Corner.....

You may remember that back at Christmas 2016 one of my presents was the OO gauge kit from PH Designs for Ivor the Engine. It's taken me a while but I've now made a start on assembling the kit.


The first step was to separate the main chassis component from the etch and then solder bearings into the frames. The kit is designed to use wheels with 1/8" axles but the 1/8" bearings I already had wouldn't fit in the holes in the frames as the walls of the bearings were way too thick. As you can seem I'm using a set of bearings from Nairnshire Modelling Supplies which fit perfectly within the etch.


There were some odd issues with little tags on the etches (not where the tabs hold the part to the fret but elsewhere, almost as if it hadn't etched properly) but in general the cleanup was easy and the bearings soldered into place without incident. I did have a bit of an issue when folding the chassis though. While folding down the frames was easy enough, and two lengths of 1/8" silver steel rod kept everything square, it was impossible to get the step down at the back of the chassis to fit properly. In the end I snapped off the final part of the fold, reduced the length ever so slightly and then soldered it back into place -- hence the slightly messy solder joint. It might just be that I didn't quite get the fold right in the middle of the line (quite wide fold lines) rather than an issue with the part itself. Anyway so far so good.

Next up will be sorting out the wheels...

Sunday, July 29, 2018

From the Footplate Downwards

If you cast your mind back about a month (before I finished the Clayton and started back on Canopus) I was looking at tiny chassis for a project, specifically the power bogies from a KATO Centram. Having settled on a chassis I've been slowly designing the rest of the model.


So far I've finished the footplate downwards; the body will be an all etched affair that slots onto this base. The test print fitted fairly well (a couple of support pins need resizing slightly for a better fit) so I better get on with designing the rest of it.

As to what it's a model of...... I'll let you guess a while longer yet.

Monday, July 23, 2018

Unlined Black?

I've now started on painting Canopus, and the question arises as to what colour it should be. The instructions suggest that at some point it had a striking livery of emerald green with red and yellow lining, but that it was also seen running in unlined black. I'm not sure I've got the patience for a complex lining job, and as I don't currently have a black loco, I think I'm going to go for a reasonably well weathered unlined black look.

Currently the chassis has been retouched by hand to cover damage to the original paintwork done before the wheels were permanently in place, and the body has been painted with red oxide primer and then matt black.


Even with an unlined black livery there is plenty of detail painting and weathering to do, but it's nice to be on the home straight now.

One interesting point about the black paint. In the past I've used Humbrol Matt Black (No. 33) from an aerosol can, but as I no longer have a convenient model shop (I do miss Antics in Sheffield) I can call into on my way home I had to buy the paint online. A quick look on Amazon and I was amazed to find that the Humbrol paint was costing £11.48 for 150ml (yes I know it's cheaper from other sellers but I have Prime so why pay for delivery or wait for ages for it to arrive). I had a look around and instead bought matt black from Hycote -- I use their red oxide primer which is excellent. Amazingly this comes as a 400ml spray can and costs just £5.09. Coverage seems to be excellent and it dried nice and quickly (as does the primer) so that's me happy.

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?