Ian_C's workbench - P4 and S7 allsorts

Discussion in 'Workbenches, including workshop techniques.' started by Ian_C, 21 May 2017.

  1. Threadmark: Handrails and knobs

    Ian_C Western Thunderer

    Turns out there are three kinds of handrail knob on the 8F (probably different again on the tender). Two short ones on the smokebox door. Eight the same size on boiler and smokebox. Four odd ones on the firebox. None of the remaining cast knobs were long enough for the boiler and smokebox so I looked elsewhere. I ended up buying a few handrail knobs from Slater's and from Eileen's Emporium, both turned from brass. I could get all three sizes from Slater's but only long ones from Eileen's. Dimensions are shown below...
    7mm handrail dimensions table.jpg

    It would be useful to have this information on the respective websites. I'll add the missing dimensions for Eileen's' when they turn up.

    Of the two the Slater's look slightly better. The ball on the end is closer to scale and it does make a difference. Both need easing out with a cutting broach to take a 0.9mm handrail wire. And both look a little chunky in the stem. Slater's long are a close match in length (A) for the boiler and smokebox knobs so they were put in the little Proxxon drill to have the stem and mounting flange (E) slimmed down a bit with a needle file. Easy enough.

    The firebox handrail knobs are a different proposition. They are mounted to the firebox by a triangular flange and three bolts. There are cut outs in the firebox cladding sheets for these but you can see in photos that the flange and bolt heads are slightly proud of the cladding. Use standard knobs and ignore the difference? Or do it the hard way? Here's the hard way...

    Face off a short length of brass rod and set it upright in a toolmakers vice on the milling machine. Find the centre and drill the centre 1.2mm diameter and the triangular bolt hole pattern 0.5mm diameter. Drill down the rod far enough to make four and a spare including the width of the parting off tool. 6mm just about covers it, which requires a bit of patience with the 0.5mm drill. Then back to the lathe to part off a number of discs 0.25mm thick. Each disc has the required hole pattern in it. Remove the parting off nib and carefully file them triangular using the small holes as a guide.
    firebox handrail knobs 1.jpg

    Insert 0.5mm wire and a Slater's medium handrail knob (modified as before) and silver solder them together. You have to take care to line up the triangle with the handrail orientation, and making everything a push fit helps to keep it straight during soldering. I'm now using a silver solder and flux paste for small parts like this. Just the tiniest blob of paste on the end of a cocktail stick is all it needs and they solder beautifully with just a waft of blowtorch.
    firebox handrail knobs 2.jpg

    Snip off the excess wire and clean them up. I have to admit to using my fingernails as a filing guide on this sort of work so my RH index finger nail is interestingly grooved right now!
    firebox handrail knobs 3.jpg

    I'm going to fix the handrail knobs to the body and leave the handrail off for painting and weathering. Particularly weathering, where you can't have convincing streaks down the boiler with a handrail in the way. I'm counting on being able to thread the handrail on at the end and paint it in situ. There's a slight kink in the handrail at the junction of boiler and smokebox (curse Churchward's tapered boilers and smokeboxes !) but I reckon it'll wriggle through as I've not made the handrail knobs too tight a fit on the handrail.
    J_F_S, matto21, Prairie Tank and 17 others like this.
  2. michl080

    michl080 Western Thunderer


    great work. I have bookmarked this post. Finding matching handrail knobs is always a PITB. I have browsed through my own locker and found some cast knobs from Weinert. Find the corresponding dimensions below:

    No 2712: A=2.2, B=2.5, C=1.3, D=0.6, E=1.2, F=0.8
    No 2713: A=3.0, B=2.5, C=1.4, D=0.6, E=1.3, F=0.8

    P A D likes this.
  3. P A D

    P A D Western Thunderer

    Hi Ian,
    Your insanity knows no bounds! Scratch building handrail knobs! :D Love it.

    Joking aside, I have a Gladiator Stanier Mogul that has these fittings for the firebox so I'll need to come up with something as well, or take the first option you mention. Shame you didn't make 5 and send one to Laurie Griffin to make cast ones.:(

    As to leaving the handrail off for painting, would it not have been better to fix the triangular base to the firebox, add all the knobs loosely and then solder in the rail and remove the rail and knobs as one. I've taken to doing it that way as I believe it is easier to ream the holes in the boiler if they have clogged with paint, than do the same to the knobs if they are in place. The whole rail is then fitted after painting and the knobs secured with a tiny blob of PVA.
    Peter Cross likes this.
  4. Ian_C

    Ian_C Western Thunderer

    Dunno, I've never done this before. You might be right! In which case you'll be able to read about it here, as I try and sort out the mess.

    The other way of doing this would be to have some triangular plates etched with half etch bolt heads. That'd be dead easy, if you can do the art work, or find somebody who's willing to, and you want about 200 of them! At some point I need to get my act together and have a go at etch artwork for the number, works and tender plates that I sort of mentioned many posts ago. I could add a handful of triangles to the artwork.
    michl080, Rob Pulham and P A D like this.
  5. Threadmark: Slow progress with little things

    Ian_C Western Thunderer

    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.
    vac water trap front.jpg
  6. P A D

    P A D Western Thunderer

    Hi Ian,
    Super job on the water trap. I added a representation of the trap to my Duchess but yours is the dog's bollards.

    May we see some pics of the oil boxes please?

  7. Threadmark: MOK 8F oil boxes

    Ian_C Western Thunderer

    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.
    oilbox 1.jpg
    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.

    oilbox 2.jpg
    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.
    Phil O, michl080, Dan Randall and 5 others like this.
  8. P A D

    P A D Western Thunderer

    Considering the extremely cruel close ups, they look pretty good to me especially as they have the lids. Are these filed into the base or separate pieces soldered on top?
  9. Ian_C

    Ian_C Western Thunderer

    Separate pieces of NS silver soldered on top. Cut somewhat oversize and then filed back to give the right overhang after soldering. Saves having to accurately position the blighters during soldering.
  10. Threadmark: 8F sabbatical and a different thing entirely

    Ian_C Western Thunderer

    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.
    935k2 vaillant white 1.jpg
    935k2 vaillant white 2.jpg

    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.
    beemax etch parts 1.jpg

    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...
  11. oldravendale

    oldravendale Western Thunderer

    Phil at Hobby Holidays has some of his etches produced on a plastic backing with no tabs.

    Rob Pulham and Dan Randall like this.
  12. Dan Randall

    Dan Randall Western Thunderer

    I didn't know that was possible until I saw Ian C's post - I detest removing etches from the frets and filing off tabs!


  13. Threadmark: Smokebox weights and speaker installation

    Ian_C Western Thunderer

    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!
    weights in smokebox.jpg

    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.
    speaker 1.jpg
    speaker 2.jpg

    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.

    under smokebox.jpg
    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.

    speaker in 1.jpg
    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.

    Attached Files:

  14. Ian_C

    Ian_C Western Thunderer

    The other bit I don't understand is how they've managed a half etch and a full etch from one side?
  15. paulc

    paulc Western Thunderer

    Hi Ian , this was all planned for during the build ? I'm trying to install a sound decoder and speakers into a L& Y class 27 with working motion , a sealed boiler and motor gearbox in the firebox . Decoder and one speaker can go in the tender and i think i may have found room , just for a sugar cube speaker under the loco between the frames but i will have to make my own enclosure to suit the odd shape available .
    I didn't build the loco by the way but this is a hobby and I'm having fun . I keep telling myself this .
    Cheers Paul
  16. Steph Dale

    Steph Dale Western Thunderer


    It doesn't really need to. Sound travels faster through solids (i.e. the loco body) than it does through gasses (like air). What you're actually doing by putting in a sealed box is just providing some additional stiffness to the speaker - lowering its resonant frequency. It may be less efficient driving a volume of fairly stiff air, but you may well find that the sound quality (especially bass) is better than if it were fully open.

    Having tried it (and measured the results) the last thing I would do is put the speaker under a chimney in a steam loco or under a fan in a diesel. These are small speakers and have a tendency to 'beam' their sound very directionally. If you squirt it up a chimney you have the additional distortion produced by the chimney itself acting as a Helmholtz resonator with only one resonant frequency. So you end up needing to wind the decoder's volume control round the end stop to get the sound to 'fill out', it deafens anyone who stands over the loco (like any operator/driver) and the sound that does come out is distorted because of the low power on the decoder and the small speaker, both being over-driven.

    At this point I usually refer people to the QSI paper, which I've already posted hearabouts (and if I'm lucky will be linked below) now that QSI have taken it down. It's a sensible middle ground; I think your installation is likely to work pretty well and is similar in principle.


  17. Scale7JB

    Scale7JB Western Thunderer

    On my K2 I put slidebar oil pots with scale hardware nuts soldered to the flange. I think you're right about not being worth it, as even I had forgotten they were there until I read your post. :))

    Rob Pulham likes this.
  18. Ian_C

    Ian_C Western Thunderer

    Some science ! That's really interesting. Thanks for the link. I guess I'll see what happens when I connect it up and work from there.
  19. Threadmark: Front vacuum pipe and associated clutter

    Ian_C Western Thunderer

    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.
    buffer beam box.jpg

    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.
    vac pipe bracket 1.jpg

    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.
    vac pipe bracket solder.jpg

    This is what you end up with after soldering.
    vac pipe bracket solder 2.jpg

    Having fixed the bracket with silver solder it's easy to add the clamping strap with soft solder.
    vac pipe bracket solder 3.jpg

    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.
    vac pipe bracket complete.jpg

    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.
    vac pipe and trap install 1.jpg

    All done, and the ugly bits hidden behind the AWS bash plate.
    vac pipe and trap install 2.jpg

    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.
    Pencarrow, matto21, fenman and 8 others like this.
  20. Threadmark: Couplings - should be straightforward?

    Ian_C Western Thunderer

    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.
    LG min coupling.jpg

    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
    coupling parts.jpg

    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.

    front coupling.jpg

    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.
    Last edited: 8 September 2019