Ian_C's workbench - P4 and S7 allsorts

[Ian_C]

Slow progress recently, but still progress. After sorting out the handrails I spent an age working out the quantity and location of the small oil boxes on the platform. They don't feature on any of the drawings in the Wild Swan book so it's down to photos and observation. In the end I found a couple of excellent hi-res broadside photos of preserved locos that showed the oil boxes very clearly. They're not the same each side either. Usual caveat about copying preserved locos. Wasn't looking forward to making 8 of the tiny things so avoided doing that for an age. Eventually scratched up from odds n sods of brass and soldered in place. You hardly notice them but the theory of authentic clutter says they should be there, so they are. Also added the oil boxes to the top slidebars which I missed much earlier in the build

There's a finishing list on the iPad now and it's filling up with tedious little jobs faster than I can cross them off. Today's contribution was the water trap in the vacuum pipe beneath the front buffer beam. It is quite noticeable so it does need to be modelled. As usual no casting for this so made from some small brass turned parts and brass wire. Another piece of clutter filling up the otherwise empty spaces below the platform.

 

[Ian_C]

Sure, you can see the oil boxes. Spoiler - they're a bit underwhelming...

Just scratched up from odds of brass and NS. Bit of a fiddle, but easy enough.

These are on the LH framing, and there's another out of shot to the left where the mainframe rises above the framing to meet the smokebox saddle. They're positioned differently on the RH side.


Here's the one I missed early on in the build, on the upper slide bar. I attempted to represent the hinge with a couple of piercing saw notches. Not sure it was worth it.

 

[Ian_C]

I always wanted to visit the Porsche museum, so this summer plane & train to Stuttgart and I did just that. Plus this year they have a 50 years of the 917 exhibition. If you were a teenager in the 70's this is what proper racing cars looked like. Brilliant place, and well worth a visit if you're into cars, and racing Porsches in particular. Bonus - Mercedes Benz museum is a short train ride away as well. Might as well do them both!

Never had a go at modelling cars but, with a head full of Porsche, I thought I'd give it a go.



The Porsche 935 is a bit of a favourite. It's an absolutely outrageous take on the classic 911 Turbo (really the 930 but it went to market as a 911 Turbo) for racing in groups 4 and 5. This example is a 1977 935 K2 in the white version of the Vaillant sponsor livery. It's in 1:24 scale and from the Beemax kit. Built pretty much straight from the box. The fact that it's a non working model feels like a holiday compared with eight coupled and Walschaerts. Nothing whatsoever to do with railways, but hey, Heather gets away with some very interesting excursions into military aircraft and vehicles so why not?

Quite pleased with it as a first attempt. A couple of minor screw ups, but lessons learned. It's very different from the modelling that I'm used to but I've learned a few things that are transferrable to railway modelling.

The car modelling community makes a big effort to achieve a high quality paint finish. None of your etch primer and a coat of grubby BR black here. I've never really enjoyed the painting and finishing of railway models so this was a real test of patience and discipline for me. It was a lot of work. Grey filler primer over the plastic body shell. Flatting down with micro abrasives (never come across this before but there are abrasives for flatting down paint (and polishing metal come to that) as fine as 12,000 grit - for example Micro Mesh) and white primer. More flatting and touching up with white primer. More flatting followed by a white base coat. More flatting followed by 2 grades of abrasive paste polishing. Decals (and applying some of these decal to complex surfaces makes most railway decals look dead easy). When the decals are set then it's finished with a high gloss clearcoat. When that's set hard it's back to very careful flatting out of any defects and fine abrasive polishing. Finished off with a wax polish and buff. You don't really see it in these photos but the finish is glassy (except in a few places!). There's a darn sight more work goes into this than I've ever seen described on a railway model. If you're aiming for an ex-works locomotive finish and shiny buffers I reckon this is the way to go. Swindon paint shop would approve. Interestingly typical enamel paints are rarely used. It's acrylics or paints derived from 'real life' car paints tweaked for modelling. There are specialist paint suppliers such as Zero Paints who will have a go at colour matching airbrush sprayable paint to your own spec, intended for cars and bikes but I daresay they'd match railway colours if they had a decent reference. The Zero primers are excellent and I'll probably use them in future in preference to the usual model railway paint products.

Another eye opener is that even on injection moulded polystyrene kits it's quite normal to mix in resin cast parts, etched metal, rubber and other polymer parts and put the whole lot together with cyano adhesives. Makes for somewhat faster working than waiting for solvents to evaporate and harden or epoxies to set.

The etched parts were a surprise to me. They seem to be in stainless steel and very finely etched. Actually stainless isn't a very obliging material to bend and some of the tiny parts are an absolute a**e to form up. Also many of the parts are etched right around with no tabs to the surrounding etch frame. Instead the metal has a clear adhesive film backing and the parts remain fixed to that after etching. The advantage is that there's no cutting and cleaning up of tabs or any risk of distorting small parts in the process. To remove a part you just cut around the backing film and peel it off the loose part. The small parts here are bonnet clips and seat belt harness metal work. Very small parts and very cleanly etched with a cusp so tiny it's not worth trying to remove.


There's already a 1969 917K in gulf livery and another 935 variant in Jagermeister orange livery in the stash.

Well that was an interesting and enjoyable holiday project but now it's complete I'm itching to get back to the 8F . Better read my last 8F post to see where I got to...

 

[Ian_C]

The lead weights for the smokebox were made some time ago. Now all of the parts projecting into the smokebox have been fitted the weights can be relieved to clear obstacles like the handrail knobs, ejector exhaust elbow and steam pipes, after which they can be epoxied in place. Once they're in they're not coming out again and there's no going back!


The weights were sized to balance up the loco and arrive at a decent finished weight, and to leave enough room for the speaker.

The speaker is a Zimo unit with a bass reflex box (well, that's what it says). It needs to be removable so it's fitted to a subframe made from thick styrene sheet with a threaded brass boss glued to the underside.



One thing that puzzled me initially was how, if the speaker was fitted inside the boiler, the sound was supposed to get out. In this installation the speaker is just below the chimney hole. The chimney casting and the hole through the smoke box wrapper are opened right out to the proper size and that's quite a big hole. The steam pipe cover castings are open to the underside of the framing and the weights are relieved to allow some noise to escape that way. There's clearance down each side between the speaker and the weights and the lower part of the smoke box wrapper has had slots cut in it to allow some sound to be projected downwards between the frames.


Here's the ugly view from beneath the smoke box showing the boss for the fixing screw and the slots cut between the smokebox saddle formers.


Here it is with the speaker installed. The wires will run back down inside the boiler and under the cab to a connector, details still to be worked out. This is all new to me and frankly I'm making this up as I go. I squeezed in the biggest speaker I can and hopefully enough whooshing and clanking will find it's way to the outside.

 

[Ian_C]

This is one of the tedious little jobs on the loco body finishing off list. Actually it's two of the tedious little jobs - bonus.

Having run forward under the LH framing the vacuum pipe is connected to a moisture separator and drain behind the front buffer beam. It sits below the level of the buffer beam and is quite visible. Also the route of the vacuum pipe from the separator across to the actual vacuum stand pipe is visible from in front at low level, it all has to be represented on the model somehow. The separator was covered in an earlier post.

The first job is to provide something to mount the pipework to. There are some rolled steel channel sections behind the buffer beam on the prototype, presumably to transmit the drawbar loads to the frames. They're not present in the kit, and as the etched buffer beam is plenty stiff enough on it's own, they don't need to be. They do however provide the mounting surface for the vacuum pipe bracket so it's worth putting something into the chassis to locate the bracket and provide a substantial mounting for it. I simply made an L angle section from scrap etch that fits between the frames and provides the correct mounting surface, not forgetting to make a hole for the front drawbar.


The vacuum pipe casting in the kit isn't perfect but it's OK and I don't fancy scratch building a replacement. What it lacks is the funky little bracket that connects the vertical pipe to the front framing. Scaled from the drawings and the parts made from bits & bobs.


The bracket was first silver soldered to the casting. That might have been a difficult job to set up for soldering but the soft heat resistant blocks I use make it easy to drill holes and make slots to hold the small parts in place. Here the tail of the pipe is dropped into a drilled hole and wedged with a scrap of NS. A slot for the bracket was carved with the tip of a scalpel. The pipe can then be rotated over the bracket and positioned for soldering. The height of the bracket was worked out by holding the vac pipe in position on the buffer beam and marking the top surface of the framing.


This is what you end up with after soldering.


Having fixed the bracket with silver solder it's easy to add the clamping strap with soft solder.


The strap is made over size and filed back to match the clamp. The chances of me making the strap exactly to size and soldering it on in exactly the right position are about nil. I didn't bother to add the bolt heads to the strap - seems like more trouble that they're worth at this size.


The whole lot is manoeuvred into position and soldered on. On the prototype there's only the front framing bracket and the stiffness of the vacuum pipe keeping it all steady it appears. That leaves it rather vulnerable on the model. Also the diameter of the cast vacuum pipe is a little over scale and doesn't match that on the separator sub-assembly where they meet behind the buffer beam. To overcome those problems there's a short length of brass rod (1.5mm I think) soldered to the pipe join and the buffer beam L angle section. Mercifully it isn't noticeable on the model from normal viewing angles. And yes, the pipe bracket really does hang down that far below the pipe.


All done, and the ugly bits hidden behind the AWS bash plate.


Postscript on the AWS bash plate. I'd assumed there wasn't one in the kit so made one from scratch (earlier post). Whaddya know? When searching the etches for something else I found the parts to make an AWS bash plate, not mentioned in the instructions.

 

[Ian_C]

I bought a pair of screw couplings from LG Miniatures for this build. There are screw couplings, and then there are screw couplings. There are plenty of variations on the theme depending on parent company and period. The type of couplings used on most LMS locos had two links from the hook to the first trunnion, and not the more common 'D' link. LG has a set of parts fo this type, 9-007 MR,LMS,BR Locos. They're very tidy little castings and they look the part. There's a problem though, particularly with BR period locos with an AWS bash plate. The screw is cast integral with the trunnions and on the LG couplings that leaves the tommy bar pointing either directly forwards or backwards. Either way it doesn't sit well with the AWS bash plate.


An idle and unproductive hour looking at 8F photos shows that most couplings were just left to hang and the tommy bar ended up lying flat across the bash plate. Interestingly very few lower links seem to have been stowed in the slot provided for the purpose at the bottom of the bash plate. Maybe freight crews couldn't be bothered, or maybe at typical freight speeds the coupling didn't flail around to a bothersome extent. I considered re-drilling the tommy bar hole perpendicular to the original and that would have allowed the tommy bar to lie across the bash plate, but when coupled it wouldn't hang down like the prototype. The only solution to that is to have a screw adjuster that actually rotates in the trunnions.

CPL does have a variety of coupling kits where the screw adjuster actually does work. Link to CPL couplings. Unfortunately the one type missing from the CPL range is the LMS type. The owner of the CPL range, Paul Bambrick, tells me that there exists a Tony Reynalds master for the LMS type of coupling but the owner isn't interested in selling, so for now it'll remain a gap in the range (unless somebody produces another decent master - anybody?). My solution was to make an LMS type coupling using a combination of LG 9-007 and CPL-30 (BR screw coupling) parts. There's not much to choose between the CPL and the LG parts so far as quality is concerned, they're both decent castings, however working from both sets of parts allows you to choose the ones you like the best. Also worth noting that the CPL kit provides a few spares for the parts that might not always cast well or may be easy to mes sup during assembly - sensible and generous! The parts laid out in the photo below are :

• Hook - LG
• Link pin - CPL
• 2x top links - LG
• Trunnions - CPL
• Screw - CPL
• Lower D shackle - LG
• Tommy bar - from scratch

A few notes on assembling the couplings may be useful. The link pin, hook and the top holes in the upper link are all about the same size so they fit together without too much free play after a little cleaning up with a cutting broach. The lower holes in the LG links are a little too big for the spigots on the CPL trunnions, so they were cleaned out, filled with solder and re-drilled to suit. The links need a slight joggle to accommodate the change on width from hook to top trunnion, and that's there on the prototype too. The lower trunnion needs to be tapped through 12BA and needs the be opened out with a 1.00mm drill first. The screw is interesting as it's all cast. I wouldn't have thought you'd be able to cast a decent 12BA thread but it comes out workable, if a little imperfect. I found that carefully running a steel 12BA nut down the thread helped to tidy up the thread form. No idea what load it'll take before it strips but probably plenty for a model, and anyway, who's going to live long enough to build enough 16 tonners in S7 to test it out? Not me for sure! CPL supply a brass lacemaker's pin for the tommy bar and LG cast the thing. Neither seemed quit right to me so I made a replacement from 0.6mm brass wire and a couple of turned ends. One thing to think about is the means of retaining the top end of the screw in the upper trunnion. The CPL couplings come with some etched buffer beam plates and some small etched washers (there's one in the photo above). I think one is supposed to solder a washer to the end of the screw projecting through the trunnion. I did this for one coupling but it's so small and there's so little solder I wonder how much load it'll take before pulling through. For the second coupling I turned a small brass boss, which makes a better job. You can just see it in then photo below. A supply of gumption, some breath holding and careful soldering gets them all put together.



Most of a weekend's work and it's OK, and the tommy bar can sit in its natural position now, both uncoupled and coupled. I notice it's not hanging quite straight in the photo, but it's not a tragedy. Reasonably happy with the result.

 

[Ian_C]

The cab roof is another job that's been continuously pushed down the to-do list in favour of easier stuff. Can't put it off any longer I'm afraid, and it did turn out to be a bit of a performance.

I wanted the roof to be removable to make assembly of the cab interior detail and painting of the cab easier. The design intent of the kit is to solder the roof to the cab front and sides, so some modification was necessary.

The kit provides an etched roof (flat), a sliding ventilator part and a half etched plate for the rear of the roof to represent the section that can be unbolted to enable lifting gear to get to the rear of the drag beam. The cab profile is not an easy shape to form, consisting of a sequence of curves and straight sections. After a lot of careful bending and tweaking I got a reasonable fit onto the cab but it was clear that I'd never get it to sit down perfectly. For fixing I'd considered small screws inside the cab, springy wire clips, micro magnets, but none of them seemed straightforward. The solution I adopted was to avoid fighting the springiness of the formed roof and make it a rigid lid that dropped into place and was retained by gravity and friction.

First step was to make some stiffening ribs to hold the cab roof to the required profile. The etched cab roof rib that was already part of the cab assembly was unsoldered, tacked to a scrap of N/S sheet (0.7mm ish) and scribed around, and repeat. Piercing saw and files get you two very stiff ribs of the correct profile that can be soldered inside the roof. The etched rib is the uppermost in the photo below. I included some prongs at the ends of the rib, and they will locate in some slots cut in the cab side flange.


One rib was soldered in place just far enough back from the front edge to to be clear of the inside of the cab front sheet. The other sits just in front of the etched cab frame rib. This means that the longitudinal ribs provided in the kit that fit between the cab front sheet and the etched rib can't be used. They don't serve a purpose any more so bye bye. The kit intends the cab roof to be located by tab and slot. The tabs on the etched rib can be filed off and the slots near the front of the cab roof can be soldered up (the two small scraps of brass in the photo below). Now the roof is fixed to the exact profile, there's no springiness and it's become a rigid unit. The other bonus is that it can be held by the rather substantial ribs for the work that follows.


With the ribs fixed, their positions on the cab roof flange can be marked. Well, almost. The etched cab sides have a flange above the windows to stiffen the top edge of the side sheets (I guess) and to provide something to solder the edges of the roof to. To prevent distortion of the window frames when the flange is bent there's a long relieving slot etched along the bend line. It certainly prevents the top of the window frames from being distorted but it all but negates any stiffening effect. Also the only areas where the flange is attached happen to be where the roof ribs are, so cutting a locating slot there makes the stiffening flange minimally attached. The remedy is to solder a length of 0.5mm wire inside the bend and fill the slot with solder (dotted line in the photo below). That makes the whole thing far more solid and we can cut locating slots without a problem. The locating slots are circled red in the photo below. If the slots and prongs are matched very carefully the roof can be a gentle press fit into position and be accurately located on the cab. A lot of words, but I hope it's clear from the photos.


With that problem solved we can look at the cab roof detail. The Stanier roof is quite a dog's dinner of plates, angles, rivets, rain strips and beading and of course the ventilator hatch. The simple etched parts look a bit 2D and don't do it justice. More hairshirted tomfoolery follows of course.

The rear edge of the roof (1/8" plate on the prototype) is finished with an angle section to stiffen it and stop rain dripping on the fireman. The angle is 1-1/2" on the prototype, and that's about 0.9mm in 7mm scale. I represented this with a strip of brass soldered to the edge and filed to shape. Rather than try and position a tiny strip accurately it's easier to solder on a wider strip in roughly the right place and file it back to size. It helps to anneal the brass first to make it easier to bend. Here it is soldered in place.


File the lower edge of the strip flush with the inside surface of the cab roof first. Then mark 0.9mm offset from that edge and file the top edge of the strip back to that line. Finally cut the ends off the strip to match the edges of the half etched overlay plate.


There's worse to come. The cabs had a beading section running from above the cab side wing plates (to which the cab doors are attached) up the rear edge of the side plate and following the roof edge curves around to butt up to the end of the aforementioned angle section at the rear of the roof. It's a surprisingly chunky section, measuring 2-1/4" x 3/4" with a sort of shallow 'D' profile. That's 1.3mm x 0.45mm in our world. That was made by making some 1.3mm wide strips about 60mm long from a sheet of 0.45mm N/S.


There's a lot of bending in both planes and the strips need to be annealed to make that possible. Heat them to a gentle red with the mini torch, pick them up with tweezers and wave them around in the air for few seconds. That cools them fast enough to anneal them fully, and they're very pliable to begin with. I started at the top and worked my way around the cab curves and down to the wing plates. This time the strip has to be accurately positioned so that it's centred on the edge of the roof. No bodgery and filing to shape permitted here. I pre-formed the initial curve along the rear edge of the roof and tack soldered that in position first. Then it was a case of working along pressing the strip into position and tacking. Note that the more you bend and re-bend the strip the more it work hardens and may eventually fatigue through and break. It's easy enough until you get to the last bend where it runs down the rear of the side sheet. The roof has to be placed on the cab to form that bend and because it's quite a tight bend across the flat of the strip it's an a*s*.


Because the roof is to be removable the bead strip has to be cut near the junction of roof and side sheet. I chose to make the cut where the bend straightens out. It means there's a little bit of beading projecting from the cab roof corner and the roof has to be handled carefully thereafter to avoid bending it out of shape. The final short straight section of beading on the rear of the cab sheet is positioned to match. When it's all tacked in place it can be carefully soldered along its length. The final task is to create the D section by rounding the edges with files and wet & dry. You can see the break in the beading here, and I'm hoping it'll be less obvious when painted.


The roof edges on the prototype were formed up into a semi-circular rain gutter about 5/16" outside radius. Can't really replicate that at this scale, but a flat edge doesn't look right, so a length of 0.3mm brass wire was soldered along the edge and blended in. Of course it's not the U shape of the prototype but it looks the part at a normal viewing distance.


The etched part for the roof vent was a bit clumsy so a replacement was made from a scrap of N/S closer to scale thickness. It took a bit of research to figure out whether there was any detail on the ventilator. The cab drawings in the Wild Swan book show that the whole ventilator hatch was riveted together. Eventually I found a good photo looking down onto the roof of a Black Five which had an almost identical cab. Looks like the small rivets were flush with the surface and don't show at all. There were four bolt heads along the rear edge and they were made from 0.5mm wire soldered through holes and filed down. Here's the finished roof in position. A lot more work that I'd imagined, and I hope the Modelu crew appreciate it when the scaleseven Toton drizzle doesn't run down their little resin necks.

 

[Ian_C]

Just for fun* , the water valve control for the live steam injector. The handle's about 3mm long. A bracket from NS scrap, a tiny turning, some 0.6mm wire and a little 0.5mm wire, all silver soldered together.


* - legal definition of 'fun' that you were previously unaware of.

 

[Ian_C]

When I made the oil boxes for the framing I forgot to make some for the cab. Two varieties; 2 x larger oil boxes with two outlets each, for the rear axleboxes I think, and 1x smaller oil box with three outlets, which I assume is there to lubricate the damper control linkage beneath the cab.

A bit of 'how to ' for those wot's interested. The basic section (1.5mm x 1.8mm) was milled from some 1/8" brass strip. The angle on the top for the lid was filed on and the section cut into oil box lengths (2.7mm) and cleaned up. The outlet positions were marked on the bottom of the boxes by eye using a sharp scriber to make an indent. That's usually just enough of an impression to start a small drill. The holes were drilled using a pin vice, 0.5mm for the small box and 0.8mm for the larger. Short lengths of micro bore brass tube were pushed into the holes and snipped off over long. Some pieces of scrap etch were cut well over sized for the lids. The whole lot was cleaned and silver soldered together (Linbraze TOS155-HA30-W1 silver solder paste with flux , 630C, in 10g syringe applied with the tip of a cocktail stick - makes it easy). Various stages of finishing and cleaning up shown below. I have to say that taking photos of your work like this does show up all the carbuncles and provides some motivation to improve.


That's definitely the last of the oil boxes. Unless there are some on the tender - I'm not going to check.

 

[Ian_C]

Here's where I've got to with the cab interior.





Still a few things left to do. I see that the oil box on the reverser pedestal is a little wonky, needs adjusting. The cab windows need to be fabricated. I'll be trying to use microscope cover slides for the glass so they might be thin enough to make the sliding window actually slide. Slaking pipe and valve on the fireman's side. I think there was a section of steel tread plate beneath the firehole. Cab doors. Fall plate. Now I think about it there are quite a lot of things left to do!

There's one minor mystery though, and something I overlooked when I was detailing the backhead. The official LMS cab photo shows (if you look carefully) a heat guard to the left of the firehole to save the driver's legs from intermittent roasting when the fire doors are open. I doesn't seem to be present on any of the preserved 8Fs so far as I can tell. Was it a 'great idea' that was quickly discarded? Something that's not favoured in preservation? Would it be present in BR day's (and I can't find a cab interior photo from the BR period)? Anybody know?

 

[Ian_C]

How to fix the backhead into the cab and still have it easily removable? A magnet glued to the inside of the backhead, and a piece of steel fixed to the cab front sheet spaced off so that they just make contact when the backhead is in place. The magnet was from Eileen's Emporium. Hopefully the pics make it clear.



In other news... there's a small valve or tap that controls the supply of water to the slaking pipe/coal watering pipe/fizzle pipe/whatever. No castings that look anything like or can be butchered, so have to make from scratch. Some tiny turned parts, scrap etch and bits of wire. Silver soldered together.

 

[Ian_C]

Hi Ian , my microscope slides tend to fall to pieces if i look at them the wrong way , i wish you luck with a sliding window .

Here's one way of cutting microscope cover slides to size. Daresay there are other methods, but this seems to work most of the time for me. You can get cover slides in various thicknesses, look on Ebay or Amazon. The ones I have are by Amscope and between 0.12mm and 0.16mm thick. You get a box of 100 for £peanuts. That's pretty thin, and they're correspondingly fragile, but they're close to scale thickness (about 1/4") so window frames don't have to be over thick and the glass edges are not obtrusive where they're visible.

This is how I cut them...


You need something to scribe the glass. I use a tungsten carbide tipped scriber sharpened to a dead sharp point with a fine diamond abrasive hone. Some folk use a diamond record player stylus in a pin chuck, but I've never tried that. You need to work on a rigid surface. Any bending of the glass as you scribe causes it to break in uncontrolled directions. I draw the shape I'm cutting in fine pencil on a scrap of printer paper (90g/m2, but I don't think it's critical as long as it's not too thick and squishy). The paper is placed on something solid and flat, in this case a turned steel blank I use as a an anvil and mini surface plate. I use a lollipop stick as the straight edge to guide the scriber. It's kinder on the glass than a steel rule. Position the cover slide over the pencil marks. Hold the non-waste side under the stick, firmly enough to stop it sliding around but not so hard that it breaks the glass. I've found that the section of glass held under the stick is less inclined to break. Draw the scriber gently over the glass. You don't need to press down at all if the point's really sharp. It creates an almost invisible line on the surface of the glass. Often it'll break as soon as the line's scribed. If not, then pick it up and place the line over the edge of the stick with the waste section overhanging and gently bend the glass. It'll snap along the line. I use a lump of BluTack to pick up and move the glass pieces around. The diamond abrasive honing stick is also good for smoothing or shaping the edges of the glass, radiused corners etc. Light touch required and work along the edge of the glass rather than across it. You break a few to begin with, but once you get a feel for it it's surprisingly easy. I find the reject rate is about one in three. Make a few spares as you go! Better wear safety glasses as well, sometimes bits ping around when you break them.

The sliding window frame's a bit of a head scratcher at the moment. You're only defeated once you've given up, and I've not given up yet. Next post probably!

 

[Ian_C]

Paul C - I don't have any problems cutting standard windows , it was the fact that you wanted to make a sliding window with all its flexing that got my attention . Any luck yet ?

After epic diversion (design & make projects for non-modelling purposes) and distraction (making a tool & cutter grinder), here's where I've got to with the sliding windows.

Attempting to follow the prototype is usually the right thing to do, and the windows on the prototype slide in cast brass channels, so we need to make some tiny channel sections. Opted in the end to machine them from brass. The best way of doing that seemed to be by cutting them with a slitting saw. Except...I didn't have a slitting saw. Well, not a proper one. I did buy a cheapo slitting saw arbor and some saw blades ages ago, but they seem to have have been designed and made by somebody with no understanding of engineering principles and didn't look like they'd be able to cut anything. (Lesson continually re-learned: bargain engineering equipment from the hobby engineering trade is usually pants. Save up for proper stuff, it actually does the job it's intended for!) Besides I needed something much smaller for this job. The channels scale to about 0.5mm wide in 7mm, and small saw blades of that thickness are readily available. Though I'd have a go at making my own slitting saw arbor.


For maximum rigidity the arbor is machined directly from a 3MT blank arbor. I've sacrificed depth of cut for a bigger clamping disc and a bigger friction radius. The blade location spigot was machined directly onto the arbor with the 3MT in the lathe spindle, so a minimum of run out on these small blades. That was easy enough to make. Of course I don't learn the lesson do I? I bought some 'reasonably priced' blades (0.5mm and 1.0 mm thick) and whaddaya know? The hole isn't exactly in the centre of the blade, so I have some runout after all. Having purchased 30 odd teeth, only one or two are actually doing the cutting. At least there's no wobble so they cut the correct width - count yer blessings.


1 - You can probably make out the dimensions and method from the sketch.

2 - A piece of 3mm brass was cut over sized and soft soldered to a sacrificial length of 3mm strip. Needs to be big enough to hold the channels far enough above the vice to give the slitting saw enough room.

3 - Trammed up to perfection in the milling vice and reduced to 1.3mm thick.

4 - Making the first cut at the top and working down from there with cuts at various depths using fine feed on the quill and table Y.

5 - Unsoldered carefully from the base strip and cleaned up. Worked out better than expected. Need two more for the other side of the cab...

Some modelling might actually happen next.

 

[Ian_C]

Things didn't quite work out the way I'd planned. 'Planned' is a strong work in this context. Superficial thinking is closer to it. There's a lot of fudgery in scaling down the cab sides and window components: etch thicknesses, overlays, accumulated assembly tolerances etc. The channels I'd made were almost exactly to scale, but because of fudge they held the rear, inner window frame too far inset from the front outer frame. The channels were soldered to a piece of NS scrap and filed down from 1.3mm wide to around 1.0mm. Next problem: I'd soldered a piece of brass wire into the angle of the folded flange along the top of the cab sides to reinforce them. Seemed like a sensible thing to do at the time, but it got in the way of the upper channel, so had to be removed.

I've looked at a lot of 8F photos, and the only ones I've seen with the rear window closed in the rear position are on locos being delivered new into service, glossy black and shiny buffers. Every loco in service seems to have the rear window slid forward to the fully open position, although I bet they'd be closed heading north from Settle Junction in the winter! Similarly I've never seen an 8F with the front window slid back to open it. Therefore I've no qualms about soldering the front window frame directly in position. I should mention in passing that the MOK kit provides the two inner window frames etched as one part, so they need to be cut apart to do this.

With that done, the channels were trimmed to length and tacked in position. Working inside the partly assembled cab was a pain. Access for soldering irons and assorted prodders and holders is limited. At which point the next problem became apparent. With both channels in position it wasn't possible to fit or remove the sliding window frame. Doh! The answer was the shorten the upper channel so that when the window is slid fully forward beyond its normal fully open position it can be disengaged from the upper channel and removed. Some cruel close up photos show how it worked out.

Here the rear window is slid fully to the rear in the closed position.


Some explanation on this photo showing that whereas the lower channel runs the full length of the cab side, the upper is shortened.


Here it is with the rear window frame slid forward almost to the point where it disengages from the top channel, at which point it can be tilted inboard slightly and lifted out of the lower channel.


The glass made from microscope cover slides (previous post) will sit neatly in the half etched recess on the inside of the frames.

Just got to do the driver's side now. Since the front windows will always be closed, and the rear windows always open I have to wonder if it was worth the trouble!

The next challenge is to make the tiny wind deflector screens that project from the cab side between the side windows.

 

[Ian_C]

8Fs carried a works plate, or builders plate, usually on the front frames. LMS built 1942 Crewe, etc. What I can't figure out is whether there was one each side or one plate on one side. If one plate, then which side? You'd think it would be easy to figure out from photos, but it isn't. You only ever get to see one side on a photo, and finding decent LH and RH photos of the same loco at about the same time is difficult. I think I can find evidence for all of the above on some locos at some times. Some locos seem to have changed sides at some point, plus later in the 60's it looks like some didn't carry plates, or at least there's an oval patch in the frame crud where a plate used to be. Any logic or system to this?

After a long pause I'm back to thinking about getting some sets of plates etched. Any recommendation for a photo etch company that'll look after a first time etcher?

 

[Ian_C]

Wind deflectors were fitted to the cab sides between the front and rear windows. They seem mostly to have been left sticking sticking out at 90 degrees to the cab side. Roughly they're a hinged frame, a bracket top and bottom and a sliver of glass. They're bigger than you'd think, so can't really be left off. I can't find any parts for them on the etch, so they'll have to be made from scratch.

I started by modelling the brackets approximately in CAD to get the sense of them. They're small parts at only 0.9mm top to bottom, and 2.0mm wide.


I milled the bracket section into a length of brass, and just marked the hole positions with a the tip of a small centre drill. Easy enough to do on the milling machine by DRO. Set out a few spares as well! Once off the mill, the holes were drilled through 0.35mm as nearest match for 0.33mm brass wire. Each bracket was cut off the length with a piercing saw and cleaned up. The pivot holes were centre marked by eye with a sharp scriber and drilled through 0.35mm again. This is about the limit of what I can handle at the moment. Holding the parts and seeing what you're doing at this size is just about possible. As the photos show, the usual tools and techniques don't give a crisp shape and finish working at this scale - at least when I'm using them! Watchmakers do remarkable work on parts this small and sometimes smaller, so it is possible.


The assembly was designed to be pinned together with wire for silver soldering. It was set up carefully on a soldering block, the wire being pushed into holes drilled in the block. Used tiny amounts the 630 C paste applied by the end of a cocktail stick.


Gentle heating was necessary to avoid melting the small parts, particularly the wire. Watch very closely and when all the joints just flash silver then stop. When it's cooled, carefully tease it out of the block. Looks a bit goofy at this stage.


Snip off the excess wire and clean it up. I did manage to make the piece of glass from microscope cover slide, that's what you see in the photo. I found it impossible to clean up the edges neatly. Even with the finest diamond abrasive I couldn't avoid edge chipping. In the end I made the 'glass' from a scrap of Cobex. Much easier to handle at this size.


Here's one installed, with Cobex glass. Slight disappointment that I ended up with the brackets slightly too close together, so they don't site quite right on the beading around the windows. The lower bracket is in the correct position, the upper slightly low and just resting on the beading. I'm hoping it's not too noticeable on the finished model. The glass tapers in at the top, presumably a loading gauge consideration. The taper on the glass looks a bit shallow in the photo. I ought to make a better one!


That's another nadgery little job done. Cab wing plate handrails and cab doors next on the list.

 

[Ian_C]

FWIW, the 8F at Highley has one each side. I can't imagine that this is a preservation mod!
Dave

Hmmm. The only photo I can find of 48142 at about the right period, shows that there wasn't a plate fitted to the RH frame. Although it looks like there's a trace of where one used to be. There's an electrification flash fitted partly over where it would have been. My assumption is that there's a plate fitted on the LH frame, although that's not visible in the photo. I note that the next Irwell 'Book of the 8F' is out now, and it does cover 8142. I put the book on my list to Santa, and I have been quite good, so maybe more info will be forthcoming. I mean, how do you get eight reindeer and a high cube sleigh onto this roof? And some of the old tiles are quite fragile... Whereas Gresley chose some excellent racehorse names for his pacifics, Santa seems not to have given it much thought when he was handing out names for reindeer. I suppose 'Comet' wasn't so bad - 45735.

 

[Ian_C]

Well, I must have been good enough, as there was a copy of The Book of the Stanier 8F 2-8-0s - Part Two: Wartime Engines 48126-48297 - Irwell Press, ISBN 978-1-911262-28-2 under the Christmas tree yesterday morning. If you're into Stanier locomotives and 8Fs in particular then it's highly recommended (along with Part One).

Amongst the other delights there are two new photos of 48142, and some gaps in the history filled in. You'd imagine it did some work at Toton, as it subsequently moved to Annesley and then Kirkby. One of the photos shows it out working in 1966 as a Kirkby loco. So Toton wasn't the end of the line for 48142.

None the wiser on works plates though. 1965 = no plate on RH frame. 1966 = no plate on LH frame. Early 1960's at Cricklewood = definitely a plate on the RH frame (and electrification flash in a different position, not covering plate location). Is it possible that from 1965 onwards it carried no works plate?

Anyway, Happy Christmas to all. And if I don't post again over the holiday period, Happy New Year as well. In spite of everything, is it too much to hope for a little sanity and peace in 2020?

 

[Ian_C]

Ian

Those are some lovely wind deflectors but wouldn't it have been better to add the glass after painting.

Richard

Yes, I will. They're just temporarily in at the moment so I can see what I've ended up with.

 

[Ian_C]

The BOT8Fs Part 2 from Irwell serendititiously has a couple of excellent close up photos of cab doors on 48133 and 48131. I'd turn them into art prints and hang them on the wall if I could. Browsing lots of 8F photos reveals that there were several minor variations of the cab doors, mostly to do with rivet positions and the extent of beading (if it is really beading, it looks like wooden wear strips in some photos) around the edges. Since I've no idea which details were present on 48142, I've chosen a combination that I'm happy to model.

Comparison of drawing dimensions and photos with the etched kit parts persuaded me to make some replacements from scratch. The signature features on the doors are the hinges. They're very chunky and held together with battleship rivets. The first job was to sketch the hinge parts in CAD and establish sizes and rivet positions. Since they're such small parts there's not chance of adding rivets accurately to finished hinges. Therefore several hinge rivet patterns were pressed into a scrap of NS using the (t)rusty GW rivet press. It doesn't get used much, and hardly ever using the graduated slides, but this time it was just the right tool for the job. It doesn't take many rivets before I start wondering if there's a better way. And waddaya know, there's dude in the US who has actually made a CNC rivet press...
Computer Controlled Rivet Embossing Machine


Door blanks were cut from more NS (0.27mm I think - didn't measure, just felt about right), and we have some parts to start work.


The cutting of hinges from the pre-rivetted strips was a trial, and you need several of them. I made a few spares of course - there'll soon be enough parts in the vacuum cleaner to build another loco. The vertical strips appear to be a half round section, and they were made from brass wire filed half flat. All the fussy soldering was done with the RSU and tiny chips of 145 degree solder. Here's one door compared with the kit parts. Scribe lines are regrettably heavy, hopefully I can buff them out.


There's some vague provision on the kit parts to hinge the doors using (I assume) wire. They can't be rigidly mounted to the cab because the rear edges will bear on the tender (...yeah...the tender eh?...) at some point and there will be relative movement between loco and tender to accommodate. Low wattage light bulb moment - I used some phosphor bronze strip behind the doors to act as springy hinges. The strip is only spot soldered at the rear end and the middle of the forward door section. That leaves a reasonable length of strip free to flex. Sorry about those lower door rivets - freehand innit?


I discovered at this point that the hinge positions I'd estimated were a little at odds with those of the kit. Since there's an etched notch in the cab wing plate for the door hinges I need to make a wing plate overlay to cover them up.


Having fitted the wing plate overlays (and neglected the opportunity to add some missing rivets to them before soldering - duh!), the door assemblies can be fitted to the cab.


The downside to this approach is that the hinge strips show inside the cab. Hopefully they won't be too sore thumb when the loco's painted and the crew are drawing attention to themselves. They spring inboards and return quite nicely with little force needed. Another potential problem is that the loco body now needs careful handling to avoid damaging the door hinges. There's not a lot left to do on the loco body now, so hopefully they'll survive.


Bonus material - maybe.

Files. One great distraction activity, when I'm faced with a modelling task that I'm not too enthusiastic about, is wasting time on You Tube pretending to look for useful information. For once, at least, it bore fruit. I came across some horological wisdom on files and filing here...

. Since we tend to do a lot of filing it's worth a watch. Something I'd not thought about before is 'safe edges' on files. Not safe as in 'occupational health & safety', but safe as in a surface that won't cut. Armed with that nugget of information, I took the small Vallorbe escapement file out the the workshop and ground one of the edges smooth on the cutter grinder. Heresy, I know. It made filing some of the hinge internal corners a whole lot easier. Rubbish photo, but you get the point. Recommended.


Flux and soldering cleanliness. I pay a reasonable amount of attention to cleaning up parts before soldering. Wet & dry, scratch brushes, wiping clean with IPA, and all that. I use Fluxite paste flux for a lot of work - stays where it's put, good fluxing action and is easy enough to clean off afterwards. The tin of Fluxite I have was inherited from my late father, and goodness knows how long he'd had it! I remember it being part of his tool kit when I was a little boy. It occurred to me that the murky dark brown paste in the bottom of the tin was actually quite filthy. Filled with grit, solder blobs, dust and 60 years+ of accumulated workbench detritus. I guess I'm emotionally attached to the tin, so rather that throw it away I cleaned it out and refilled it with fresh paste from a new tin of Fluxite (they still make the stuff). Surprisingly fresh Fluxite is a pale yellowy colour, not a dark brown. Unsurprisingly fresh, clean flux works much better than old, mucky, degraded flux. Who have thought it?

RSU electrodes. I have an old Exactoscale RSU. Bought it on an impulse at a show a long time ago. Less than full price, and quite possibly Bernard Weller's prototype unit! Utterly unsophisticated, but it works well. I also acquired a small plastic bag with a dozen or so copper coated carbon electrodes for the probe. They don't get used up very fast so they've lasted a long time. They're not the sort of thing you come across when you're out shopping, so when I stumbled across some on eBay I thought I'd restock. The eBay electrodes turned out to be a revelation. They're much denser and harder that the Exacto originals (closer to the charcoal end of the spectrum!), and that makes them much easier to shape to a point and much less prone to crumble in use. It's made soldering of tiny details much easier with a properly pointy point. Wish I 'd discovered that years ago.