Thursday, August 21, 2014

Canopus: Pipework

With this post I'll have finally caught up with the current state of the build at which point updates may slow down as I move onto the more complex task of getting the thing to move under it's own power. So without further ado, let's talk about pipework.

You'd already seen one small piece of pipework when I added the balance pipe, but I've now added the injectors, the vacuum pipe for the break and the lubricators to the front of the saddle tank. Only the long pipe that provides the vacuum for the break is permanently fixed, the injectors and lubricators will be permanently fixed after painting, along with the handrails.

Strangely the instructions don't mention the pipe for the vacuum break, but not only is it clearly visible on photos and the works drawing, but there is a hole for it in the etched cab front, so I made it up from a simple piece of brass wire. The rest of the pipework are cast brass fittings. Unfortunately I managed to break one of the injectors when removing it from the fret.

I'm not sure how the injector pipe broke as I didn't exert that much force, but the long section snapped in the middle. I did try soldering it back together, but the joint looked horrid and didn't seem particularly strong. In the end I cut of the broken sections, drilled holes in the two end parts and then fabricated a new pipe from brass wire. This was then slotted into the drilled holes along with some solder paint. A quick touch with the soldering iron and I had a repaired injector, which looks the part.

You may also notice that I've moved on from using a piece of wire insulation to hold the coupling rods on. Now each rod is properly attached to all three fly-cranks with a small nut. These are amazingly tiny and very fiddly to fit, especially as the bolts are cast so not a perfect screw thread. They will eventually need fixing permanently and then the remaining screw cutting off and the bolt filing thinner but that will wait until I've got the motor in so I can check the movement is nice and smooth and make any necessary tweaks.

Tuesday, August 19, 2014

Canopus: Joined Up Motion

List time you saw the chassis for Canopus I'd fitted the wheels and the cylinder bracket to complete the basic rolling chassis. Since then I've added the fly-cranks and coupling rods to both sides (so the wheel quartering is done). I was a little worried about doing this but as you can see the chassis is still rolling nicely and looks great with the body rested on top.

The next stage is to build the gearbox. Unfortunately this may take a while as I've discovered that the supplied parts won't build into a working gearbox. Since the kit was originally designed some of the parts have been replaced, and this includes the gears. Unfortunately the change in gears means that they will no longer stay in the correct position within the gearbox so I'll need to figure out a sensible way to proceed. I have some ideas, but I'll need to get some more supplies from my local model shop before I know if I have a working solution.

Canopus: Balance Pipe

Now I'm not quite sure what a balance pipe is for, especially on a locomotive with, as far as I know, a single water tank, but it is worth noting that the dimples marking where it should fit on the saddletank casting are in the wrong place. All the drawings and photos I've seen of Canopus show the pipe curling tightly under the boiler just to the front of the tank filler cap. If, however, you look at the saddletank casting the dimples are positioned just to the rear of the filler cap.

Fortunately this is easy to fix by simply drilling holes into the casting in the right place and using a little filler to cover the old dimples (and the first hole I started to drill in the wrong place). Once the saddletank is glued to the boiler fitting the balance pipe (just a bit of 0.8mm wire formed around the handle of my modelling knife) is nice and easy.

Now if you remember I hate fitting handrail knobs to the saddletank. Having eventually got them right, I've had to do them again, as I've discovered that the saddletank casting appears to be slightly twisted. I glued it into position and checked that it looked level from the front (i.e. the bottom of both sides were level) and that the tank filler cap was in line with the chimney etc. It was only once the glue had set solid that I discovered that at the cab end it isn't so level, which of course meant that the handrails weren't level. I did try to break the glue to re-position the tank but it isn't coming off, so I've tweaked the handrail holes slightly to try and get them level back to front and at the same height on each side. They aren't perfect but for normal viewing they will be fine; it will only be a close up inspection from directly in front where you might notice a problem.

Monday, August 18, 2014

Canopus: Reversing Gear

So the next detail added to the body was the reversing gear. Annoyingly I didn't think to take a photograph of the part before I'd fixed it in place so it is now a bit difficult to see how it goes together. This was quite a fiddly part to make as there are three etched parts and some brass wire to be soldered together.

The reversing lever is made of three etched parts; the main lever and the rod the protrudes through the cab wall, and then two toothed gear racks. The three parts are held together by two small pieces of wire that slot through all three parts at both ends of the toothed racks. As I'm sure you can imagine holding all this together is a bit tricky, but worth it as the result is a very fine representation, such a shame really that once the model is finished you'll almost never see it; another good reason for keeping the roof removable.

Sunday, August 17, 2014

Canopus: Freewheeling Chassis

So having started the day with a post on another body detail I thought I'd focus on the chassis for Canopus in today's second post. The last time you saw the chassis I'd added all the overlay detail but had yet fitted the wheels and soldered it solid. Well I've now added the wheels (including the insulating washers) and soldered on the cylinder bracket and the front cross-member to complete the basic rolling chassis. Rather than a photo I thought I'd show that the chassis runs nice and smoothly even without the extra weight of the body.

While I'm happy with how well it moves now, I'm hopping it still moves that freely once I've fitted the fly-cranks and coupling rods. I'm a little worried about fitting the fly-cranks as I've just realised why reaming out the axle holes was such an involved process.

The instructions mention that the fly-cranks should be an interference fit on the 1.5mm axles. I had a quick look to see how well they would fit only to find that they don't... at all. A little bit of measuring and I've discovered that the supplied wheels (which a packing note explained differ from those in the instructions) are actually on 2mm axles. Clearly the bearings that were supplied fit the axles, but the chassis etch obviously hadn't been updated so rather than just a small amount of reaming to get a push fit, I had to remove 0.5mm of extra material. On the chassis and axleboxes this wasn't a problem (other than being time consuming), but I'm a little worried that once I've removed the extra material from the fly-cranks that they might be a bit fragile.

Canopus: Handrails

I'm sure most modellers have something that they find difficult or hate doing. So far, my pet hate is handrails. I had real problems getting them right on the Quarry Hunslet loco and fitting them to Canopus hasn't been much easier.

Initially I thought they would be fairly easy to do this time as the saddletank casting had six small dimples in the right places for the handrail knobs. All I would need to do was to drill the holes at an appropriate angle. Having struggled with this before I knocked up a holder, inspired by Paul using a V block, from a small mitre box and some cardboard and then set about drilling the holes.

Annoyingly having drilled the holes on one side I found that while the two end holes were fine the middle one was well out of position. Rather than trying to fill the hole and drill a second one, I decided to just stick with two handrail knobs on each side of the saddletank. Strangely while the kit suggests three per side, and a works drawing Paul sent me also shows three per side, every photo I've seen only shows two, so I'm happy with just two.

Once I'd drilled the holes and checked the alignment I gently tapped the wire to the saddletank and then used a small drop of solder paint to fix the knobs to the wire. I've now reduced the wire to the correct length and tided up the solder, but I haven't fixed them in place as it will be easier to paint the body and then fix the rails in place, so for now they are neatly labelled (which side and which way around) and stored in the box with the remaining parts.

In theory Canopus should also have a curved handrail attached to the front of the tank that wraps around the chimney but I wasn't convinced that it looked great so I've filled the holes and will leave it off. As I'm not intending to create an accurate copy of Canopus I'd prefer to like how it looks and not add a part just for the sake of doing so.

You can also see from the photo that I've glued the filler cap to the top of the tank which I think completes the fittings I can add before I glue the tank to the boiler.

Saturday, August 16, 2014

Canopus: Cab Roof

I know I've already blogged today, but I've now got quite a few detailed bits of Canopus to blog about so I thought I'd do a second post today to try and catch up. The last time you saw the body I'd fitted the boiler and smokebox (the saddletank casting was just rested on) but the cab was still roofless. The roof itself is a single etched part that needed gentle shaping to match the profile of the cab. Once correctly shaped two small etched parts were soldered on to represent a ventilator and a flange around where the whistle and safety valves will protrude.

While the roof looked good just rested in position, it obviously needed a more sensible way of keeping it in place. Now I could have soldered it to the top of the cab sides but that would leave it difficult to access the cab for painting etc. so I took a different approach (which is also suggested in the instructions). I picked up a short length of 2mm x 2mm brass angle from my local model shop and cut two short pieces to be a tight fit to the cab sides. I then used masking tape to fix these in position along the top of the cab sides, before taping the roof into the correct position. I then flipped the body upside down and tack soldered the two parts to the roof and then removed the whole contraption and added some more solder to make sure the joins were solid. The brass angle encroached a little too far down the cab sides and so was visible at the top of the door opening, so I simply filed this section away while holding the roof in place and so now from normal viewing angles you can't see the brass angle at all.

The roof is now a nice push fit to the cab and will even stay in place if turned upside down, while still being easy to remove.

Canopus: Chassis Detailing

So, as a number of people pointed out in the comments to the previous post, the problem with the guard irons wasn't that they were too long, but that I hadn't bent them to shape. Embarrassingly that was the next step in the instructions. As you can see though the chassis has moved on a little further than the guard irons.

The main chassis etch contained the outline of the springs but no detail other than a few rivets. Al the details are provided by overlays. The first job was to ream out the holes in the axleboxes so that they fit around the protruding bearings before they were soldered to the side of the chassis. Once they were fitted the spring detail etches were filed to to fit and then soldered in place.

The next step solder the rest of the chassis retaining parts in place, which means that the wheels will be permanently trapped between the outside frames. I'm currently debating if it is worth trying to add the remaining details to the chassis first so I can paint it without risking bunging up the wheels and moving parts, but the consensus seems to be to finish the model first (at least to the point of wheels, pickups, and fly cranks) and then paint it. If anyone has any thoughts though I'd appreciate any suggestions.

Thursday, August 14, 2014

Canopus: Fouled by the Guards

While I'm still working on all the detailed fittings for the main body of Canopus I've now also made a start on the chassis. Currently I've soldered the six bearings for the main wheels in place and folded the chassis so I can test fit the wheels. While this was nice and straightforward it has highlighted one problem with the kit.

Most steam locomotives were fitted with guard irons, metal protrusions in front of the wheels, which are designed to knock away small objects from the top of the rail surface which, I guess, helped to prevent derailments. The guard irons on Canopus are easy to see in the photo taken when in use by the RAF. In that photo they appear to end just below the level of the wheel axles, but this isn't the case on the kit.

As you can see the guard irons are unbelievably long and end well below rail level. Fortunately as they are part of the frames on the kit (rather than inline with the rail) they will allow the chassis to sit flat on the track. The problem is that I want to be able to run the loco on a layout where there will be a section of the track set into a road surface at which point the guard irons would be below the level of the road. Clearly this is a mistake in the kit so I'll have to file them back to a more appropriate length. On the plus side the chassis seems to sit perfectly flat on the rail and a piece of glass and the wheels turn freely which suggests I got the bearings in straight (although I did file down the flanges slightly as the clearances were a little tight).

Tuesday, August 12, 2014

A Rake of Wagons

So work on Canopus has slowed slightly, mostly as we spent the weekend at a family wedding. Having said that I have done some work on the model that I haven't blogged about yet, but I'd like to be able to explain what some of the parts are supposed to represent so I'm doing a bit of reading up first before I show you those.

So to keep you entertained I thought I'd show you the completed rake of three of the box wagons I recently printed.

As you can see the wagons don't currently have couplings fitted. I'm thinking of only fitting working couplings to each end of the rake and to permanently attach the three wagons together, but has anyone any suggestions of a good way of doing this? I have the slot in the buffer beam for the Greenwich coupling so can easily attach something else in the same place, but what would work best?

Thursday, August 7, 2014

Canopus: Fitting the Boiler

After a fair amount of filing and fettling I thought I was happy with the boiler, smokebox and saddletank castings. Turns out it still wouldn't all fit together properly.

If you remember back to the previous post on Canopus I mentioned in passing that the smokebox needed a hole drilling and tapping but that "this was easy to do as there is a dimple in the casting to aid correct positioning". Unfortunately I didn't actually check the dimple was in the correct position before drilling and tapping the hole. It turns out that the dimple wasn't correctly positioned on the casting so when the smokebox was screwed to the footplate it was about a millimetre to the right of centre (when viewed from the front).

Now a millimetre might not sound like much but on a model that is only 26mm wide it is quite a lot. What is more annoying is that I didn't spot the problem during the numerous test assemblies I did, only after the parts were glued together did I spot that they were out of line.

At first I thought I could live with the problem, but the more I looked at it the worse it seemed. Fortunately it was easy to break the two superglued joints to allow me to separate the parts and refit them. Unfortunately there was no easy way of moving the tapped hole in the smokebox casting. If it had just been a hole I would have filled it and drilled a new one, but I wasn't sure if that would work. Instead I slightly opened up the hole in the footplate that the screw passes through allowing a better positioning of the part; I will need to do the same to the matching hole in the chassis at some point.

With the boiler fitted, I attached the chimney and smokebox door handle (both of which are nice brass castings) although from these photos there is clearly still some work to do to hide the join between the chimney and smokebox, but I'll do that when I've finished the rest of the body. Currently the saddletank is only rested in place as I need to drill holes in it for handrail knobs etc.

It may have taken a while to get right but it is now looking like a really interesting little steam engine.

Monday, August 4, 2014

Aberllefenni Box Wagon

Getting the boiler to fit on to Canopus correctly is taking a little longer than expected, and as I received another batch of test 3D prints at the end of last week I thought I'd switch focus and show you my latest piece of 3D printed rolling stock.

While flat wagons and three bar slab wagons are great, most things I'm going to want to portray on a layout set in Yorkshire are (I think) more likely to need to be carried in a wagon with sides, so here we have a simple box shaped wagon. Whilst it may look at home on my layout (whenever I actually get around to building it) the wagon is actually based on wagons that were in common use in the Aberllefenni Slate Quarry in Wales. It is a fairly accurate model (it's ever so slightly too wide so as to accommodate the wheels) as it's based on a scale drawing in the Slate Quarry Album by Gordon and Ann Hatherill.

I was a bit worried that the axle boxes would be too fine to print properly but they have come out really well and the wheels turn really well in them so even unweighted they seem to run along the rails nicely. I definitely think I'll be printing a bunch more of these and if you happen to want any then, as with most of my 3D printed models, head over to Penistone Railway Works where I'll happily sell you some!

Saturday, August 2, 2014

Canopus: Retubing the Boiler

While I never expected that the kit for Canopus would be easy to put together, I hadn't expected to hit quite so many issues as I have so far. Prior to this post I had used six etched parts, one of which I broke and one of which I destroyed and had to replace. Rather foolishly I hoped that the next step would go together easier.

Having assembled the cab the next stage involves fitting the smokebox, boiler and saddletank. This actually involves four parts as the boiler consists of a brass tube and a cast whitemetal weight. The other two parts are also whitemetal castings (the kit includes both a cast and etched saddletank but I'm using the cast version as it is heavier). The bottom of the smokebox needs a hole drilling and tapping to take the other fixing screw (the first one is at the bottom of the coal bunker) that keeps the body attached to the chassis. This was easy to do as there is a dimple in the casting to aid correct positioning. Having test fitted the smokebox to the footplate I found that the boiler wouldn't fit.

The problem, as you can see from the first two photos is that while the instructions say that the saddletank "should be a snug fit against the cab ... so that it just touches the smokebox" both the boiler tube and weight are longer than the saddletank casting. The solution is easy, although rather time consuming.

First I used a razor saw in a small miter box to trim the brass tube to a more acceptable length, before then filing it to an exact match to the length of the saddletank. I then filed the whitemetal weight down until it was the same length as the brass tube. Having test fitted the parts they do fit although I haven't yet had the time to actually glue and solder everything into place so that will (hopefully) be a job for tomorrow.

Canopus: Cooking the Coal Bunker

Having added the four main walls for the cab the remaining piece is the back wall of the coal bunker. This is made from a relatively small piece of brass which needs to be rolled to match the profile of the rear edge of the cab sides. While this should be an easy piece to fit, it isn't. The problem is that given the thickness of the brass and the size of the part it is almost impossible to roll it to the right shape. The trick, apparently, is to anneal the brass which should make it easier to shape.

Annealing is basically just heating the metal to make it easier to work and the instructions say that you can do this by simply placing the part on an electric cooker hob for about 10 minutes. Unfortunately we have a gas cooker and I wasn't sure how I'd support the part in the flames, so instead I decided to use another item from the kitchen, a blow torch. Usually the blow torch is used for melting the sugar on top of a creme brulee or this excellent Lime and Passion Fruit Tart, but I thought it should be able to heat the brass well enough so I set up a sensible looking work area and turned on the blowtorch.

Now the blowtorch did seem to be able to heat the metal quite well, although even after about 10 minutes it wasn't exactly glowing, but then disaster struck as the metal appeared to bubble; I'm guessing I held the torch in the same place for two long. You can see the ripple marks on the bottom left corner, and there is also a bubble on the back in the middle. So while the part now bends much easier it wasn't really useable.

Fortunately I'd decided to measure the part (10.75mm by 23.5mm) while it was flat before I tried annealing it, so I made a replacement using some 0.25mm brass sheet from Albion Alloys. This sheet is slightly thinner than the part from the kit, but not noticeably so, and can just about be formed without annealing. I gently rolled the part using the handle of my modelling knife and then soldered it in place which definitely transforms the look of the rear of the cab.