Ian_C's workbench - P4 and S7 allsorts

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

  1. richard carr

    richard carr Western Thunderer


    I think you will get them before then, my checkrail chairs oredered at the end of March were going to take a month, they turned up 5 days later in early April !

    I think the the late delivery times are to try tog et you buy the express delivery at twice the price.

    Some beautiful drawings, I look forward to seeing the end result.

  2. Len Cattley

    Len Cattley Western Thunderer

    I can't wait to see them as well.

  3. Threadmark: Some 3D printed axleboxes, DCC first start up, and a dangerous distraction

    Ian_C Western Thunderer

    Shapeways quoted an early June delivery, unless I paid a whole load more for a 'rush/priority' service. They wanted about $250 to reduce the delivery time to about a week. 250$? That's taking the P. I'm impatient, but not $250 impatient! As it turned out the 'early June delivery' dropped through the letterbox yesterday, with the bog standard priority and lowest cost shipment. Ironic? Cynical? Anyway...the parts.

    They're printed in a translucent acrylic plastic and it's claimed that the process will resolve detail down to 0.1mm. I also opted to pay a premium for the smoothest surface finish option, just to see what was possible. This is what I got....

    Shapeways axlebox parts.jpg
    They looked pretty good out of the box. It's hard to show the detail in photos of translucent stuff, but even the smallest CAD details were present and well resolved. I'd chosen to keep the feature size to no smaller than about 0.2mm on CAD, but from the looks of this you could probably model detail right down to 0.1mm if you wished. There's still some visible layering with the 'smoothest' print option, and on parts like this there's no practical way of hand finishing to remove it. On larger, more accessible surfaces you could rub off the layering quite easily. The material files and sands nicely. I added some temporary diagonal bracing to support the hanger rods during manufacturing and handling. They're positioned so that they're easy to remove, and the scars don't show. The back of the box is hollowed out just to save material (the cost is partly determined by the volume of material) . There's a circular spigot on the base of the spring that pushes into the hole in the top of the axle box. Both modelled dead to size, and they're a light push fit. So the dimensional accuracy's good as well.

    Shapeways axlebox parts 2.jpg
    This is about as close as I can take a photo, and you can see the layering. The orientation of the layering depends on the orientation in which it was printed. I didn't specify that, it's done by the Shapeways folk when they prepare models for printing. This particular material and process uses a wax support matrix, so the design isn't so constrained as the 'build into thin air' process that a lot of 3D printers offer. Interestingly the springs were printed in a couple of different orientations, so the layering runs in different directions. You can tell if you look closely enough, but at model viewing differences I'm guessing it's invisible. We'll see.

    Shapeways axlebox primed.jpg
    It's recommended that you wash them in acetone before painting to remove any remaining trace of the support wax and uncured resin. Here's one with a coat of grey acrylic primer. Applied by brush in this instance, but I'll spray the rest along with the tender when it gets painted. You can still make out the layering, but it's not apparent at model viewing distances. Captures the look of the Stanier axle box very well, I think.

    whitemetal axlebox.jpg
    One of the cast white metal axle boxes with the same primer for comparison. They're not bad for overall size and proportion, but you can see that the crispness and fine detail gets lost at this size, and there are features of the prototype that I think would be impossible to replicate in a casting pattern by traditional means (somebody on WT is going to prove me wrong, you can guarantee it).

    Was it worth it? In terms of what it brings to the model, yes, definitely. And a decent return for two days of research and CAD. In terms of money spent, not really. I'm not going to disclose what the exercise cost (I'm still working out the domestic forgiveness strategy). Technically it's viable and the results are brilliant, but I'd have to find a more cost effective way of getting them printed, and maybe experiment with materials and print resolution to get the cost down.

    The cat's well and truly out of the bag after the stable door was bolted, and I can't help wondering how 3D printed number and works plates would turn out. Particularly since the Severn Mill chap is stood down at the moment. Hmmm...
    In other news, I've finally got around to making the DCC stuff work for the first time.
    DCC first attempt.jpg
    Ok, it's not in a loco, but after updating software and getting the bits to communicate, the motor responds as expected and the speaker makes noises. I've not set up the key press functions properly yet, so there was certain amount of pressing virtual buttons to see what happened. For a frustrating period there was motor but no sound, until the house was awoken by a surprisingly loud 8F whistle when I discovered the un-mute button. Next job is to work out how to wire it all up in the loco and tender. DCC duck broken, and I can see this has a huge amount of tinkering potential.

    This is the dangerous distraction that I unearthed from a box when I was looking for something else.
    Hunslet 15 inch kit and parts.jpg
    A 4mm Impetus kit for the 15" Hunslet. I got it from a Scalefour Soc 'for sale' ad a couple of years ago. Original and untouched, it's a rare thing these days. There are Gibson wheel sets, what looks like a High Level gearbox, Mashima 1020 motor, Kean Maygib buffers, and a load of High Level CSB jigs and parts. The kit is very nicely done, but oh so retro! Typewritten and copied instructions and hand drawn assembly diagram. Life was simpler then. Looks like it'll make a nice little engine (somewhere between Percy and Thomas in the Fat Controller scheme of things). Can you get DCC and sound in something this size, I wonder? Like I said, dangerous distraction - I really ought to finish a project sometime, before starting another.
    Last edited: 16 May 2020
  4. Ian_C

    Ian_C Western Thunderer

    As it turned out Richard, you were dead right!
    Last edited: 17 May 2020
  5. daifly

    daifly Western Thunderer

    I ordered a load of Shapeways track components last Monday (11th May) with an estimated despatch date of 29th May for the 'Economy' manufacture and delivery service. The order was despatched on Friday 15th May and will arrive by UPS on Tuesday 19th. There's an obvious moral there!
    Edit to add that they arrived on time on 19th!
    Last edited: 23 May 2020
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  6. Threadmark: 3D printed loco and tender plates?

    Ian_C Western Thunderer

    I wonder if this'll print OK? Exported from Adobe Illustrator with text as 'outlines' in either .dwg or .dxf format. Imported to CAD and tidied up a bit. Sprue and supports added. All deparameterised into a big dumb blob, exported as STL and checked over in Meshlab. The smallest letters are slightly below the claimed resolution of the print process. Probably doesn't matter much at this size as long as something's there. I've made the plates slightly thicker than scale for robust print and handling. I can thin them down a little on wet & dry if I feel the need.
    plates and sprue CAD 1.JPG

    48142 ended up with tender 9797 towards the end of its life. Still a 4,000 gallon welded type, but originally built in 1939 and put behind a Jubilee. Tender plates are guesswork on my part. So far as I can tell most tenders of this type had two plates: rectangular tender number plate above an oval water capacity plate, a few had a third builders plate. I've also assumed it had the sans serif style letters on the number plate. Some had a wacky turn of the century serif style for which Illustrator has no close match. Only the tender water and scoop plates and the shed plate had visible bolt heads, the rest having countersunk heads that don't show.

    It'll be interesting if this comes out OK. It probably won't stand comparison with the best etched plates, but it'll be a more flexible alternative for sets of bespoke plates if an etcher doesn't have exactly what you want. No good for those splendid polished brass plates on Western locos, but probably OK for typical LMS plates; a bit rough out of the foundry and painted over several times, maybe highlighted in white if you're lucky, and subsequently lost under a layer of filth.
    Last edited: 17 May 2020
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  7. Threadmark: 3D printed loco and tender plates

    Ian_C Western Thunderer

    Here's how they turned out.
    3d  plates 1.jpg

    Again, it's difficult to capture the detail on a photo with this translucent plastic. It's far better than it looks in this photo. The thinnest lettering was 0.06mm across, and it's still printed OK. Not crisp and perfect, but more or less legible. The raised edges around some of the plates have thinned out a bit and look a little ragged. It seems to be related to the direction of the print head. I can compensate for that now that I know the rules.

    Here are couple of plates coloured with a black marker pen and wiped off with a tissue moistened with IPA. They look a bit crude at electron microscope magnification, but they're absolutely fine at model viewing distance. I might do a bit better with careful dry brushing on the finished model.
    tender number plate.jpg

    Very happy with the result. It's a viable way of making plates, and I think I've found the limits of this process. Some day I'll have to have a go at etch artwork...another day.
    P A D, BrushType4, Rob Pulham and 7 others like this.
  8. ChrisBr

    ChrisBr Active Member

    If you can do 3d print artwork like this, etch artwork is an easy transition to make....
    SLNCR57, adrian and Dog Star like this.
  9. adrian

    adrian Flying Squad

    I think I'd agree with that sentiment. Given the processes involved I do think that a good quality etched plate will be an improvement on any current 3d printed method. Given some of the results members have shown with with printed transfers I wonder if you could do similar printing and etch the plates at home. It would be an interesting comparison with the 3D printed effort and also some of the laser cut versions.
  10. AJC

    AJC Western Thunderer

    The Impetus 15" is a nice kit, but as you say, very retro! Mine is ex-Bob Alderman - bought and built when the thing was new - the chimney as supplied is a bit naff (it's a cross between the Hunslet pattern and the gas producer type fitted to some NCB examples - mine was turned brass, but your whitemetal one looks the same). Impetus had a bit of a blind spot for chimneys, the alternate suplied with the Bagnall 0-6-0 was far too tall which is why mine has a Giesel...

  11. Mike Trice

    Mike Trice Western Thunderer

    You seem to be getting very obvious layering in your Shapeways prints. Are you laying them out flat or at an angle? The plates would be best flat as would the axleboxes with detail upwards. Looking at your photos the axlebox looks brilliant on the back but rough on the front. This might suggest they were printed detail side down which would result in a poorer finish due to the support material.
  12. Ian_C

    Ian_C Western Thunderer

    I don't think so Mike, although I have to say that I find the Shapeways tool for setting the orientation a bit awkward to use. On the axleboxes I know they were printed with the flat side down because that was showing the surface finish you'd expect from the support wax. Still, I've not done much 3D printing, so I expect to learn as I go. Thanks for the hint.
  13. Ian_C

    Ian_C Western Thunderer

    Not sure I agree. With solid modelling you get what you see. In so far as I've had a go at etch artwork (but not had any etched yet!) I find it hard to get my head around. Making a 3D thing from several flat things that overlay and interact. Too much abstraction - maybe that's just how my head is wired!
  14. Threadmark: The drawbar

    Ian_C Western Thunderer

    Getting down the finishing off list slowly. Today's job was the drawbar between loco and tender. First question was 'how long?' I re-opened the CAD for loco axle side play, and added the tender. Allowing a bit of clearance on 6 ft radius curve gives a drawbar length of 38.3mm. That's part way between the dimples in the drawbar casting.
    drawbar articulation.png

    Drawbar was drilled out at the required centres on the mill. Because of the way I'v only partly followed the instructions I've ended up with a M3 screw at the loco end and a 6BA screw at the tender end. Disciples of Mr Webb's Crewe standardisation, may tear their hair out. I turned up a couple of bushes so that the screws can be tightened without pinching the drawbar. There's enough clearance in the drawbar to allow some vertical articulation, but hopefully not so much that there's chatter betwteen loco and tender at low speeds. The bushes were soldered to the screws to make ersatz shoulder screws.
    drawbar 1.jpg

    And, for the first time, the tender is coupled to the loco. Feels like progress. The gap between steps is larger than scale by a little, but it can't be helped, and it's not tragic. I briefly thought about a sprung close coupled drawbar, before I came to my senses. A slight peeve is that the drawbar is secured from above on the loco, and from below on the tender. Better if both ends could be secured from beneath. You wonder about lateral forces on the tender when reversing a train through curves. Hopefully the tender will be heavy enough to prevent the flanges climbing the rail.
    drawbar 2.jpg

    The next job is to work out the electrical connections, and any dummy pipes between loco and tender.
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  15. Threadmark: Electrical connection - teeny weeny connectors

    Ian_C Western Thunderer

    I had a laptop PC apart the other day, and there were some very small connectors in it. Some puzzling and googling later, and this is what I found...

    JST SH 2 way connectors.jpg

    Just made for the job, innit? These are JST type SH connectors and headers. They're 1.0 mm pin pitch, and the smallest I can find that are readily available. They come in 2, 3, 4, 5,.....up to 20 pins. The 2 pin connectors in the photo are 4.0mm wide and 2.9 mm high. They'll carry 1 Amp, which is probably enough. Amazon and eBay will oblige; about £5 for a bag of 10 pre-wired connectors and 10 headers. I need to take 4 wires across the gap, two for the motor and two for the speaker. It makes sense to use 2 x 2 pin connectors rather than a single 4 pin. That way the speaker and the motor can be removed separately if need be. Also there are more places to fit a 2 pin connector than a wider 4 pin.

    Here's the manufacturer's data sheet for the connectors.. http://www.jst-mfg.com/product/pdf/eng/eSH.pdf?5ecacf8e5317b

    There's enough space under the cab either side of the brake cylinder to take a couple of connectors. The headers are intended to be flow soldered to a PCB to anchor them. I doubt that it would be practical to try and solder the headers to the loco chassis, so I made a couple of tiny clamps. They're machined from brass and threaded 12BA.

    connector clamps 1.jpg

    I didn't fancy measuring and marking the hole centres on the chassis, so I made a couple of small pre-drilled plates as drilling guides. They were soldered in position with the RSU, and the holes were drilled through the chassis. The clamps are fixed with 12BA screws.

    connectors installed 3.jpg

    The connectors are 'theoretically' visible when looking from the side beneath the cab, but in reality they'll be lost in the murk behind the injector pipework, especially when they're painted black. This view is with the chassis inverted looking forward from the back end. One connector header is clamped in place on the right , and you can see an empty clamp to the left of the brake cylinder.
    connectors installed 1.jpg

    Seen here from below with both connector headers clamped in position, and the pre-wired connectors plugged in. The wires will cross the gap amongst the water, vacuum and brake hoses, and hopefully not be too obtrusive.
    connectors installed 2.jpg

    It should be straightforward to solder wires to the the back of the headers and run them to the motor and speaker. The next objective is to complete the wiring and have the loco run on live track under DCC.
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  16. simond

    simond Western Thunderer

    The only downside of two two-pin connectors is the risk of applying motor power to the speaker, but I guess the locations prevent that.

    nice way of mounting the JST connectors. They are also available as PCB mounted sockets.

  17. Phil O

    Phil O Western Thunderer

    Makes them almost look like the flexible water hoses and the vacuum and steam pipe connections.
    Len Cattley likes this.
  18. Threadmark: Nearly done with the wiring, and some mechanical tweaks

    Ian_C Western Thunderer

    A couple of days of picking away at the job when I'm in the mood gets the wiring almost finished.

    I'm sure the connector board that I bought for the decoder isn't actually designed for this decoder, because the labelling on the connector board doesn't correspond with that on the decoder. So it took a while to establish which decoder output ended up where on the connector board. Luckily (?) all of the outputs I'm using all map to a screw terminal on the connector board.

    There's not much room at the back of the tender for wiring to exit the connector, so I made leadouts from lengths of solid copper wire and formed them to sit tight around the back and end up pointing forward along each side. In fact, I made solid wire 'pins' for each connector location. They're easier to insert than wire, and tolerate repeated clamping better than wire ends. They're covered with some small heatshrink tubing. Wires were soldered to the copper pins and covered with a bit of heatshrink tubing. The heatshrink insulates the joint and provides some flex relief for the end of the wire.
    Back end connector board.jpg

    Tender wiring for stay alive capacitor, motor, speaker and pick ups added. Tiny bits of heat shrink are used to keep wires together and tidy(ish). A couple of loops were fitted to guide the wires down in front of the tender wheels and under the drag beam. Motor supply is on the loco's left, and speaker on the right. And, yes, Simon, they're both black/red, and it's entirely possible for me to cross them over in the tender and feed motor supply to the speaker! To be honest, I hadn't considered that. It's 50/50 - how unlucky can I be? Coloured paint blobs on the connectors should make it clearer - thanks for pointing that out.
    tender wiring.jpg

    The speaker's right up front at the noisy end, as previously related. The wiring from that just runs through an empty boiler. I added a length of silicone tubing to protect the wires from a multitude of edges and where they squeeze past the motor in the firebox. I find silicone tubing useful for all sorts of things. You can get short lengths of the smaller sizes here... https://www.hilltop-products.co.uk
    speaker wire 2.jpg speaker wire.jpg

    The motor wires just loop round in the firebox and dive under the cab. While I was working on this I discovered why the body and chassis were always a bit reluctant to line up perfectly. The motor's offset about 1.5mm off centre to shift the gearbox across the axle enough to insert a taper pin through the axle halves. The original motor restraining bracket wrapped around the outside of the motor, and in so doing it just made contact with the inside of the firebox casting when the chassis was fitted to the upperworks. I made a different bracket that engages the spigot on the motor end piece. It allows virtually no fore/aft motion of the motor, but it can slide laterally as the compensation tilts the axle. Incidentally I've since found a data sheet for this Maxon motor. It'll draw 0.6A continuously, which is it's steady stay winding temperature limit at 25C , and up to 1.2A for intermittent overloads. So the 1A rating for the SH connectors is probably OK. It's already been pointed out that I could have used a smaller decoder :oops:
    motor wired.jpg

    This is how it ends up. It's a bit of a fiddle, and not something you'd want to be doing often. Also snookered myself, in that it's impossible to tighten the clamp for the speaker connector when the body is on. I'll alter the clamps so they can be tightened from the underside. What I've learned from all this is that any loco electrics beyond the usual pickups and motor in loco need to be thought out in advance.
    loco tender connected 1.jpg

    Still got some dummy hose connections to add. The finishing off list ain't finished yet.
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  19. Threadmark: It's been a while, but here's a little progress - the whistle

    Ian_C Western Thunderer

    Was it really the end of May when I last posted anything? Sometimes life gets in the way, and the workbench gathers dust. I have managed to accomplish something though. I made a whistle to replace the cast item supplied in the kit. Scaled from a Wild Swan drawing, it's bigger than you think. Tiny brass parts and little silver solder, cruelly enlarged here...
    whistle 1.jpg

    Things are slowly moving towards a conclusion. I've got some fresh black etch primer, and I 'm starting to think about painting. I'll be looking for some advice on painting 'BR grey', there's probably a place on WT for that discussion.
  20. FH47331

    FH47331 Member

    Hi Ian,
    I don't know if this helps you or not, but I've been doing some 3D printing recently, to get to grips with the Fusion360 software. I got fed up of the delivery times with Shapeways, but more fed up with the postage cost. So I stared searching around. There is a company called WeDo3DPrinting.co.uk based in Sheffield. The chap there is called Darren and is really helpful - they also do laser cutting of wood etc.. too.

    I rang him and said I was looking for some model railway bits and he remarked that they are doing more and more in that market! Anyway, cost wise the printing was 55-60% of what Shapeways wanted, postage was £2.50 and from sending him the files on email to getting the package through the post was three days. For anyone who doesn't have their own 3D printer, Id highly recommend trying them.

    Darren also commented that if I was near Sheffield, I could simply call in and pick them up rather than having them posted if I wanted, which could also be a boon if you needed something quickly. No connection other than a very satisfied customer. Hope it might be of interest to you.