Slater's brass SR bogies - an approach to building them

[Heather Kay]

I have decided to kick this into a new topic, rather than further confuse the Slater's Maunsell coach build thread I have going on. This topic has been prompted by Graham @Dog Star, after I kept missing out the important steps in the other thread!

I am not claiming any new ideas. The bogie kits in question are not difficult to put together for a competent modeller with the right tools. They are fiddly to build, they are time-consuming, can be frustrating at times, and the instructions haven’t been updated to match changes in the parts list.

Before I get into looking at the various components and beginning the construction process, here is the infamous jig…



Actually, that’s one-and-a-bit jigs. The correct one is at the top. The jig is essentially for one purpose only, and that is aiding the construction of the bolster. I’ll look at what they’re made of, besides sheet brass, and how I use it/them in due course.

What does the kit consist of?



Two of these etched frets. These comprise the main bogie framework and brake gear. The circled area highlights four keeper plates that retain the axleboxes and bearings. What appear to be insulators on a telephone pole are actually tags that fold back and help locate the plates in the hornguide. You will note one at the top left has not etched properly. This particular batch of etches seems to suffer from this. The location pips aren’t actually critical, though, since the plates can be positioned and soldered in place without their aid.

The square highlight top left is parts for the original bearing system. These are no longer required, although they are still referred to in the instructions.

I would also like to draw your attention to the thin edges of the scrap material at the top and bottom of the long sides of the sheet. I use these to make the angled safety loops. Such thin scrap material is often useful to keep in stock for other uses, too, such as lamp brackets and similar items.



Castings. If the bogie kit is included in the coach box, these will be packed with all the other castings in the kit. A couple of minor modifications will be made, which I’ll deal with when we get to them.



Injection moulded brake shoes, springs and axlebox covers. I’ve arranged them here so you can see both front and rear of each moulding. You will note the brake shoe runners include extra items which are intended for the plastic bogie kits. These usually find their way into my Bits Box to supplement other coach and wagon builds.





Wheelsets, top hat bearings, and the axlebox bearings and springs. The latter safely stored in a plastic pot with a lid to minimise the risk of feeding the Carpet Monster.

I haven’t shown the injection moulded step boards. They actually come on a runner as part of the main coach kit. I couldn’t find the runner in the box, so I may have to contact the manufacturer for a replacement.



The instructions. By and large, I shall be following these in the order they’re written. The note about drilling the rivet holes to take step board brackets says to use a 0.5mm bit. With the vagaries of brass castings, I find a 0.7mm hole much more reliable. It doesn’t hurt, either, to twirl a taper broach in the various etched holes to clean them out. So, let’s crack on.



Having separated the main frame and bolster parts from the fret, the first tedious job is carefully filing away the etch cusps on everything. Several parts in this build will not appreciate cusps remaining in place, plus I dislike seeing them left in place.



After some time - listen to something relaxing to pass the time, and remember to take a break to stretch the back muscles occasionally - we have this selection of parts.



Pushing out the rivets is fairly straightforward.



This is the next step, which turns the flat frame into a three dimensional object. Tackling this will be the next post.

 

[Heather Kay]

I inadvertently skipped over steps 2 and 3 in the instruction sheet. Let’s remedy that now.



With the rivets pressed out, and holes cleaned up, the axle guards are folded over against the side frames. Traditionally, etch folds have the half etch line inside. The instructions are clear to fold with the line outside. I have tinned the mating surfaces ready for the next step.



Plenty of flux, a hot iron (circa 380°C) tipped with a drop of cored electrical solder and held long enough to let the solder flow into the tinned areas. The parts were held down with a wooden stick while this was done. A quick clean up of flux spatter and a gentle scrub with a brass scratch brush to clean things up a little, and on to the next stage.



Folding the bogie end angles out. I ran my Olfa cutter along the etch fold line a few times to make life a bit easier. Even clamped in my Hold'n'Fold, it’s not an easy fold to form. I used a steel rule to push the brass over as far as I could, followed by some gentle panel beating with a small hammer to ensure it was all square.



Folding the bogie frame is much simpler. I use a pair of Maun parallel pliers to act as a small anvil and square against which to form the bends. A little time spent getting things as square as possible makes the running of a solder fillet up the inside of each corner much easier.





It is quite normal for the frames to look like this when forming the sides up. Nothing to worry about, as the sides will be pulled together when the bolster assembly is fitted. You can, of course, gently tweak the frames if you wish. You may well need to do this to straighten things up after forming, to ensure all the hornguides sit flat on the bench. You can see the far right is cocked up in the air in the second image. It pays to try and get the frames as square as possible at this stage. While inserting the bolster and A-frames will tend to straighten things, and the axles being sprung will all help, you can’t beat a square frame at the outset to avoid all sorts of pain and anguish later.



It might be pertinent to identify what all the various holes are for. The red arrows indicate a slot for the spring stop and a hole for the step board bracket. The slot has an L-shaped etch part fitted from inside the frame, forming a leaf spring bump stop. I find running a sharp blade along the slot clears any cusp in it to make the bump stop fit easily. The green arrows point to alignment holes for the J-hanger castings. Blue arrows are the brake shoe cross rod holes, and purple shows the slots for the bolster assembly. The pair of large holes, either side of the small peg at the top of the hornguide slot, are for the plastic pegs that will hold the plastic leaf spring in place.



These are the etched parts for the bolster. One set has been left unfolded for effect. The next step, you will be glad to hear, involves some castings and the bolster jig.

 

[Heather Kay]

Step 7 in the instructions looks deceptively easy. It asks us to fold up part 8, then solder the cast ends to it.



These are the cast ends in their raw state. They represent coil springs in the bolster. The wings hook into swing links a little later on. Well, they ought to hook into the links, but experience has told me I need to do some minor surgery to make the fit as easy as possible. It’s best to do it at this stage, because it’ll be all but impossible later.



It's not all that clear, sadly, but the casting on the left has had some filing done to the wings to thin and reshape them.



Now, I’ve spent some time reshaping the wings and also shaving a tiny bit from each fat locating block. I’ve popped on swing link in place to show how it’s supposed to fit over the wing. In their raw state, this is next to impossible to achieve, hence all the filing.



The act of filing the locating blocks is to ensure they fit into part 8 nicely. They only need a couple of passes with the file, the added benefit of course being the brass casting is now clean enough to be tinned.



Ready for deploying the jig!



This may seem overkill. Do I really need the gas torch for this operation? Probably not, but brass castings plus the jig materials are quite the heat sink. Even my poor old Ersa 80W iron struggles to maintain the temperature to make a good joint.



I hope you can work out the essentials here. A large piece of 0.7mm brass sheet has been adapted to let the end casting sit in alignment with the etched part. A couple of bits of thinner brass were fitted when I first created the jig to let part 8 sit between them with the trough upwards. This was a misreading of the instructions, though honestly the orientation of part 8 makes no real difference. The other parts of thick sheet are used to give sufficient gap beneath the main jig to let the end castings nestle into place neatly. It all rests on a heat resistant brick, held down by a nice big cast 4lb weight. More heat sink!



Here we see the parts put together. Note how the casting wings tuck under the jig.



Some flux applied, followed by the gas torch. I hope to see some solder begin to flow into the joints, and you can see the heat has affected the brass parts. You don’t need me to tell you to leave this well alone until it has cooled down. Once this operation is completed, the jig parts are returned to storage, on the off-chance I shall have further Slater's bogie kits to assemble.

The next stage is assembling the bolsters.

 

[Heather Kay]

Time to make up the bolster assemblies.



The cross beam is the main focus at this stage. The instructions are fairly clear, so we needn’t deviate from them. There are some things to be aware of, though.



This is a pair of the swing link castings. I usually run a 0.6mm bit through the cast holes. The slotted end should be inspected in case some cast material is blocking it. If the slot is blocked or narrow, it won’t fit over the wings in the bolster springs assembled earlier. I generally gently file the flat leg and tin it in preparation for the next stage.



Here are the cross beams, one with the swing links in place. Follow the instructions, especially regarding the orientation of the outer channels and their various slots as well as the swing link castings. It’s important the swing links are free to move on their wire pivots.



These are the spring bump stops. I’ve folded one already. While there’s still reasonable access to the frames it makes sense to fit these.



These fit along the top edge of the bogie frame sides. I’ve punished out the rivets, but they need folding to a right angle. A bit of a fiddle, but aided by running the Olfa cutter along the half etch line a few times.



The instructions would have you fit the suspension beam to the swing links, then fit the whole shebang into the frames. I find it easier to fit the cross beam assembly from earlier into the frames first, while there’s access to get the soldering iron in. Tinning the ends and the mating surfaces on the inner frames helps, too.



Here's the bolster cross beam in place, from above. You could solder from the outside of the frames, where the tabs show in their slots. If you’re fussy, you can spend time cleaning up the outer face around the slots, but with the rivets there it’s best to ignore. With the foot boards and other gubbins on, it really doesn’t show.



A couple of minutes with the Hold'n'Fold sees the angle strips formed. Tin them along the riveted side, as well as the location on the main frames.



Use a couple of Dinky clips to hold the strips in place, then solder can be run into the join from the top.





For the final point in this stage, I fit the suspension beam to the swing links. A quick dab of solder on wing each will hold things in place. It’s fun to try and make sure the beam is square to the rest of the bolster assembly! As the instructions point out, the swing links should be slightly splayed outwards with the beam in place.

Time for a break before the A-frames are sorted out.

 

[Heather Kay]

Folding out the A-frames is probably the worst part of this build. Let’s see the instructions on this.



Removing the frames from the fret, spend some time carefully filing all the edges to remove the cusps. Run a taper broach through the small holes for the brake hanger rods. The twin holes on the cross beam are for brake lever castings, which we will see shortly.

Again, the Olfa cutter along the etched fold lines really helps, as does being methodical about the order. Holding the piece to make the folds is the most awkward, and I recommend a Hold'n'Fold that can support along the length of each fold. I think the instructions are wrong here, as it shows the long sides being formed first. The cross piece should be folded first, the the ends of it carefully filed to remove the cusp. Then fold the long pieces. The final folds to bring the long angles up to the cross piece can be done by hand.



The main folds have been made on the lower pair of frames here. The final folds bring the long side beams up to the cross beam.



I have arrowed the location slots on the main frames assembly. The tabs at the ends of each A-frame will fit neatly in these, as long as you’ve cleaned the cusps off everything. I’m not just obsessed, it’s important to ensure a good fit.



Locate the inner ends of the A-frame, which occasionally needs a gentle bending of the frame to get it to the right spacing. The outer ends can then usually be slotted into the outer bogie frame slots without too much bother. The instructions do say to carefully file the ends of the A-frame to ensure a good fit, so take that as good advice. I do find the bogie end frame does occasionally need a gentle outward pressure to let the A-frame tabs drop in.



Once in place, the A-frame will be a good solid fit. I apply a fillet of solder inside the ends, just to hold things in place.



These are the brake lever pivot castings. The pins fit into two holes in the A-frame cross beams. Run a taper broach in the holes to make a good fit. I have had a situation where the castings have perhaps shrunk slightly, and they didn’t fit the etched holes. Dry fit to make sure things fit well.



Plenty of solder on the pins holds the castings in place. The main frame assembly is now finished. The next stages are fitting the wheels and brake gear, so it’s probably a good idea to give the bogie frames a rinse to clean off flux residues. This pair is off to the ultrasonic bath for a soak.

 

[simond]

Heather, sorry if I missed it, do the swing links swing or are they soldered solid?

academic question as I’m never likely to build one, just interested.

Atb
Simon

 

[Heather Kay]

Heather, sorry if I missed it, do the swing links swing or are they soldered solid?

When first fitted they are meant to swing, as it makes it easier to fit the cross beam. Once that’s done - as the whole thing is basically cosmetic - soldering up solid is the final step.

 

[simond]

Ta!

 

[Heather Kay]

Time to tackle another of my least fun parts of these bogies. Oh, alright, I admit it. I hate building these bogies! There. Said it. Now, on with the motley!

Brake rigging. Brake shoes and hangers, actually. The rigging is still to come.



First, making up the shoes. These are two parts each, a front and back. The reverse of one half shoe has a smooth surface, which is glued to the thicker detail on its opposite half. I prefer to remove the smooth face part from the runner and attach it to its mate while the latter is still attached. It makes it a bit easier to align things like this.



Here we are with the halves joined together. The row of shoes at the top are those meant for the poor folk building the plastic versions of the bogies. Destined for the Bits Box as useful detailing for other coach builds.



Now, more fun. Having trimmed and tidied the shoes, fitting the hangers. The idea is to use 0.5mm brass wire passed through the shoe and brass hanger. A drop of cyanoacrylate holds the wire "hinge" and hopefully leaves the hanger free to swing.



Should glue encroach on the hinge, gently working it back and forth to free it up usually works. The space between the moulded hinge hole and the outer edge of the shoe is very small, so care needs to be taken to avoid breaking the hinge wire out of the moulding. I’ve been there before, at least twice. With no spares, if repair is not possible replacement by bodging one of the solid mouldings is the only recourse.



More 0.5mm wire is used to make the hanger bars. I leave the outer wires long on the inside so they can be used to hang the yoke safety chains from. Try to make sure the shoes are hanging the right way round. Ask me how I know this! At this stage, the shoes remain loose on their bars. They generally remain a complete nuisance through the rest of the build, liable to accidental damage, so be careful about handling things from here on.



Half-way on one bogie. I’ve also installed the yoke levers to the cast pivots.



Slater's at this point head off and install the plastic moulded leaf springs and the yokes. With painful experience, I’ve learned to ignore the instructions. First, the yokes are easier to fit with the wheelsets in place. Second, we aren’t done with soldering. These brass J-hangers need to be fitted, and they take a bit of heat.

The arrows show a projection on the back of the centre hangers. I chop these off, as they interfere with aligning the inner pairs of brake shoes.



There are etched holes to fit and align the J-hangers. I find these need to be opened up to somewhere slightly north of 1.0mm. Clamping the bogie frame in a small machine vice leaves hands free to position the castings, then hold them while soldering. Tin all the mating surfaces. I did this stage with the Ersa, as you can tell by the mess. A resistance soldering unit might be better for this job.

Aside from the option of spot soldering the brake shoes, yokes and axle guard tie bars in place, that’s all the hot soldering for now.



I had hoped to get the final stages done today, but wrestling with the J-hangers beat me. I’m off for a lie down, while this pair dry after a final ultrasonic bath.

 

[Heather Kay]

I’m not kidding about when I say these blighters take most of a week to put together. To put it in context, I’ve generally spent about four or five hours each day working on these. The nearest equivalent I’ve come across are the Kemilway Gresley kits, which take even longer to put together if memory serves.

 

[chigley]

I’m not kidding about when I say these blighters take most of a week to put together. To put it in context, I’ve generally spent about four or five hours each day working on these. The nearest equivalent I’ve come across are the Kemilway Gresley kits, which take even longer to put together if memory serves.

i know what you mean, i ended up going the poor mans route, now whats that mans name, oh yes percy veerance. PS what ultra sonic cleaner do you have. keep up with the good work. Ken

 

[Heather Kay]

PS what ultra sonic cleaner do you have

For the bogies it’s one of those cheap things sold for cleaning jewellery. I have a much larger professional one I use for the bigger jobs.

 

[Heather Kay]

There will be a final post or two. I’m very close to finishing, and I’ve done a fair amount of the prep work for installing the wheels and brake yokes. Then I managed to break one of the shoes off…

I have walked away. I hope I may be able to repair things and carry on.

In case it’s of interest, the technique to sort it out is to snip the hanger rod to release the brass hanger loop. The rod can be extracted and thrown away, since it will be replaced in due course. The plastic shoe broke through where the wire hinge was inserted - a known issue which I highlighted up the thread. I have applied cyano to the affected area, which I hope will be sufficient to repair the break.

I shall try again tomorrow.

 

[Heather Kay]

I succeeded in repairing the broken brake shoe, so it was on to the final stages of construction. By now, I’ve thrown the instructions away because there is a better sequence to fit stuff.



First, I found the step board runner. It was lurking among the body and roof mouldings in the kit box.



Before we can really get into fitting all the brake rigging, some more decusping. Even the pegs that fit the brake shoes get a swipe with a file, otherwise they’re not a smooth fit and risk damaging things during assembly.



The operating rods get a 90° twist and I make up the safety chain loops to fit. Fine copper wire forms a split pin that gets soldered to the yoke. The chain I’m using is trimmed to four links.



A quick twist of a taper broach in the large holes at the top of each hornguide ensures the plastic pegs are a smooth fit. Forcing a peg into the hole only results in squashing it. I find it better to have it a good push fit, and then held by a drop or two of cyanoacrylate. This stage is also a good time to ensure the axle bearings are a nice easy and smooth fit. Time spent aligning and gently filing things at this stage pay off later.



With a bearing in place in the hornguides, trap the phosphor bronze spring between the pegs and add a drop of cyanoacrylate to hold it to the bearing. I also fit the top hat bearings and hold them with a drop of CA. If you’re building a Finescale O model, the top hat bearings may well need to be tweaked in the bearings with the wheelsets in the bogie to centre the latter.



Fitting the plastic pegs can be done next. They’re a lot easier to fit before the wheels go in!



I fit the tie rods between axleguards now. Much easier without the wheels in. Cut four 0.7mm brass wires to 46.5mm long. There are tiny etched recesses in the hornguides to show the location. The wires go inside the axleguards.



Now, fit the wheelsets with the spring bearings, followed by the tie bars to keep them in place. Now we can begin to fit the brake yokes.

The process is hard to photograph easily, so I’ll try to explain the process in text, but the diagram in the instructions does help to identify which yoke fits where.



Begin by sliding the yoke's end pegs into each brake shoe. Gentle poking and prodding while the bogie is right side up will help to align the shoes with their wheel tyres. At this point, the end of the yoke operating rod should align with the lever already in the bogie. Persuade a short length of 0.5mm wire into the yoke and lever holes according to the diagram. A drop of flux and a hot iron should fix the yoke in place. Realign the brake shoes if necessary, and then fix the hangers to their cross bars. I do this with solder, but you might feel happier with a drop of cyanoacrylate.

Repeat for the other yoke on the wheelset, and then do the whole thing again at the other end of the bogie. It doesn’t really take long once you get your eye in. The important thing is not to stress the brake shoes, as it doesn’t take a lot to break them.

The final act, if you’ve fitted them, is to hook the safety chains over the hanger rod extensions.

Save for the footboard L-brackets, that’s all the soldering done. If things have worked out, we should have a free running bogie with soft springing.



Fit the moulded leaf springs to their pegs, fixed with a drop of MEK or similar solvent applied by a brush. Sometimes the brass J-hangers need a gentle tweak to align them with the leaf spring. If they are too far away, there’s not much that can be done, so ignore them. You will note the left hand J-hanger seems a long way from the leaf spring compared to the right hand end. Measure them and you’ll notice about half a millimetre difference in the T-bar. Nothing we can do, just a mistake by the manufacturer.



The plastic moulded axleboxes are now glued to the moving bearing. They sit over the top-hat bearing. It’s not immediately obvious which way up the boxes go. There’s a tiny sloped faced that goes to the top. When the springs are fully compressed, the leaf spring sits just behind the slope. Finally, glue the box covers to the boxes.

The step boards can now be glued to the L-brackets, as long as they’ve survived being extracted from the runners and being cleaned up. I’ve had another one snap on me, which I guess may be a moulding flaw rather than pure clumsiness on my part.

I’ve just realised I haven’t covered creating and fitting safety loops. To see what I mean, here’s a link to a photo showing the real thing. I’ll be back later when I’ve done my homework!

 

[Heather Kay]

As far as I can work out, the safety loops - designed to catch the long brake rods from the vacuum cylinder area should they come adrift within the bogie - were only fitted to one end of each bogie. This, obviously, was the end facing towards the centre of the underframe.

I suspect the real thing was designed to be mounted to the coach underframe in a certain way, but for model purposes it doesn’t make a lot of difference. I selected one end, that with the A-frame cross bar near the bolster, to be the inner end, and tried to ensure all the bogies I’ve built are the same orientation.



Remember that scrap etch I pointed out at the start? Well, here it is. One strip will actually suffice exactly for two loops.



I made my original loops up by eye, based on the photo I linked to earlier. The actual measurements are, from one twisted end to the other, 3mm+9mm+15mm-9mm-3mm. The ends are twisted 90° so they can be soldered to the bogie end stretcher.



Perhaps not as messily as this, but you get the idea. The loops do just touch the brake yokes, which isn’t too far off what the real ones appear to do.

Well, there you are. How I go about putting the Slater's brass Maunsell bogies together. I hope you found it of use. Thanks for reading this far, Please post any comments or questions my technique might have raised.

This pair of bogies is off for a final ultrasonic bath, and then some chemical blackening ready to be painted and weathered with all the other bogies now littering my workbench!

 

[chigley]

thank you heather.

 

[Pencarrow]

I've got 2 more to make at some point Heather, made the last 5 years ago, so this will be useful.

 

[OzzyO]

Ready for deploying the jig!

View attachment 138125

This may seem overkill. Do I really need the gas torch for this operation? Probably not, but brass castings plus the jig materials are quite the heat sink. Even my poor old Ersa 80W iron struggles to maintain the temperature to make a good joint.

View attachment 138126

I hope you can work out the essentials here. A large piece of 0.7mm brass sheet has been adapted to let the end casting sit in alignment with the etched part. A couple of bits of thinner brass were fitted when I first created the jig to let part 8 sit between them with the trough upwards. This was a misreading of the instructions, though honestly the orientation of part 8 makes no real difference. The other parts of thick sheet are used to give sufficient gap beneath the main jig to let the end castings nestle into place neatly. It all rests on a heat resistant brick, held down by a nice big cast 4lb weight. More heat sink!

View attachment 138127

Here we see the parts put together. Note how the casting wings tuck under the jig.

View attachment 138128

Some flux applied, followed by the gas torch. I hope to see some solder begin to flow into the joints, and you can see the heat has affected the brass parts. You don’t need me to tell you to leave this well alone until it has cooled down. Once this operation is completed, the jig parts are returned to storage, on the off-chance I shall have further Slater's bogie kits to assemble.

The next stage is assembling the bolsters.

Heather,

sometimes you just like making it hard work for yourself. Why not just add the bottom bits of brass (about 5mm wide) to the sides or ends of the top sheet, then drill four holes in these parts to take some push pins to pin the jig down to the heat resistant block. To remove even more of the heatsink you could cut out a big hole in the top sheet.

Doing this you loose a lot of brass in the three sheets and you don't need to have a 4lb lump of metal acting as a very big heatsink.

Nice looking build.

OzzyO.

PS. very late to the party (or early if you look at the time I'm posting this).