3D printed Y7

[mick b]

Does the Loco work as I cannot see any coupling rod in the picture ?

[auldreekie]

Those Couillet/Decauville parts look great.

I was going to apologise for hi-jacking your thread, but it looks as if I needn't, since normal service has been resumed.

As regards NBR locomotive details, for John Coffin's benefit, I'm pretty sure I have material at home which gives fairly detailed dimensions of chimneys, domes, etc. Not works diagrams or any such thing, but I'm sure quite good enough one versed in CAD etc to use for 7mm scale modelling purposes, and therefore certainly for 4mm scale (which would be my interest). I don't have chapter-and-verse to hand, but I shall try to remember to provide it in a couple of weeks' time.


auldreekie

[Brack]

Mick - it does - the chassis on it is a fleischmann 7000 (german n gauge 040t). I should've had the rods down for the works photo, I know! the motor is within the firboax, whilst the boiler, saddle tank, smokebox & saddle are full of lead.

This morning the wheels, buffers, smokebox dart and coupling rods arrived from Alan Gibson Workshops (only ordered them yesterday at about 3pm - great service!), as did the gears. I have a nice little 12V gearmotor (runs at 140rpm) with a 3mm shaft (one of these sort: http://img.dxcdn.com/productimages/sku_181704_1.jpg, got a pair of them from ebay for £6 including postage!), so ordered some 3mm bore 1:1 bevel gears from here: http://www.motionco.co.uk/gears-bevel-g ... 32_41.html. They're pretty nice, but the boss on the back of the gear is huge, so I've cut the boss off one (razor saw) and am spending the morning reaming it out to fit a 1/8" axle (surprisingly hard - the plastic is pretty tough on these) whilst watching some cricket. They should just about fit between the frames and provide a simple drive mechanism. Of course you could use a normal motor/gearbox (probably one of the slimmer ones - there's only 10mm between the frames as they're thicker than brass), but I haven't got any of those in stock.

[Brack]

so, finally finished it all, and I've sent a big order off to shapeways (the Y7, a CIE Cement Bubble, in 4mm/ft, a chassis block for a H0m Billard railcar, an O9 Bagnall 042T Annie, as on the groudle glen, some O scale bagnall NG driving wheel centres, and a pair of 7mm/ft African Spur thighed toroises - my O9 layout is set in Southern Sudan, and for some reason its hard to find figures/livestock!). This doens't mean fo course that I'm getting all that - Shapeways have proved time and again that they will reject prints for rather spurious and hugely inconsistent reasons even when you've followed the design guidelines (I had a model rejected as unprintable after they'd printed 24 of them over the previous year, the last of them only a week previous. At the time I had 3 of them on my desk so I offered to send a photo to show that they could print them, they just repeated the same "unprintable" line again, with one person quoting thin walls, another claiming too many shells. I changed the filename, reuploaded it, and lo and behold it printed and has continued to do so. I think its down to the whim of the person operating the machine...). Hence I wait until I have a big order to maximise my chances that something will get printed and sent back to me!

Having said that, as a customer (ie. not a designer) Shapeways have very good customer service, pretty much unbeatable quality for the price, and when I have had the odd shoddy print from them they've refunded without argument. I guess the trouble is that compared to most of their customers who seem to want tacky rings or phone cases, scale railway models with high detail are a bigger hassle to clean up and harder work for them.

Now just a wait until I either get the order or they start rejecting bits - pictures will follow in due course.

[Brack]

in case this is of interest to anyone else....

this is how I'm powering my Y7 (I hope - if it doesn't work then I'll have another think)


apologies for the rubbish photo quality.
this is the 12V 140RPM gearmotor I mentioned (they were £6 for 2 from eBay, intended for operating locking mechanisms, videocamera zooms etc, either way they're cheap and run smoothly. The bevel gears are the motionco ones I referred to earlier, 8.7mm diameter, with a 3mm bore (which is correct for the motor shaft). The gear on the axle is the same type, but I 'adjusted' it with a razor saw (it really doesn't need a 6mm boss on the back of the gear, and it wouldn't be fitting between any frames with that left on) then using some cutting broaches, bored it out to fit on the 1/8" axle. The motor is 12mm x 10mm and 24mm long including gearbox, with the shafts sticking out 7-8mm on each end. The rear motor shaft is 1mm in diameter. You coudl try and fit a flywheel on it, but there's not much room inside the Y7 for that (I'm driving the front axle, with the motor angled up toward the cab).

I'll let people know how the drive mechanism works in due course. I hope to have the thing working (and at least part finished) in time for the show at north shields, if it comes soon! (I'm not exhibiting, but a friend has asked to see it).

[Brack]

OK, my big Shapewyas order came today, after opening things, a 5 minute wash with alcohol in my £3 chinese ultrasonic denture cleaner, a rinse and a dry this is what we have:



There are several varied scales/gauges on there, so be patient (4mm scale CIE cement bubble body, 7mm/ft Bagnall 042T Annie of the Groudle Glen Rly, the Y7, a chassis block for a H0m Billard railcar, 7mm/ft african tortoises for my Sudanese layout, and some 7mm/ft Bagnall driving wheel centres for small NG locos).

I'm afraid the material doesn't photograph well until you've painted it, but hopefully this should give you an idea. The Y7 is printed with the chassis suspended beneath the body on 4 little sprues, which you can cut with a scalpel or razor saw and file flat.



Once the chassis is off, then the 4 brake shoes and 2 clack valves can be cut off their sprues (inside the frames) with a scalpel and tidied up with a file.



This shows my gearmotor/bevel drive, on the inbuilt mounting bracket I put in (unless anyone else want to use it, I'll probably leave the bracket off the production versions as it's visible in the frame cutouts - if you want to copy my choice of motor/gears, PM me and I'll make the original available as well). the romford bearings are perfect push fits in the frames, as is the motor, and hold quite firmly without any screws/glues, though I'll probably fasten them anyway.



The body is located on the chassis by 2 little pegs protruding behind the buffer beams, which engage in slots in the chassis. There is a 0.5mm hole through the pegs, so to secure the body on you'd just need to put a little bit of rod/wire through them.

I'm hoping to crack on and get it a bit more presentable by the North Shields show on the weekend, as a few people have said they wouldn't mind seeing it. Perhaps there'll be a 00 layout that might give it a run out...

First Job - get the chassis working.

[mick b]

Looks very nice , any idea on prices ?

[52D]

I echo Micks post, very tidy any idea of price c/w motor and gearing.

[Brack]

The body & chassis will be sold through my Shapeways shop (https://www.shapeways.com/model/1264797 ... r-ncb.html) I'll make it available once I've got my chassis working (I always print everything and check it works before making it available to the public). The price for the body/chassis will be 60 euros (about £50). The beauty of selling through shapeways is that they handle the sales/post etc. and I don't have to keep stock (I have a day job and a family, I only became a supplier accidentally). The gearmotor is a 10x12mm 12V 200rpm motor (25mm or so long, with a 3mm diameter shaft) from here: http://www.ebay.co.uk/itm/Dual-Shaft-12 ... 4ab1ceccca They're 2 for £7 inc post, and you can get them in different speed/ratio (mine are 140rpm, if its too slow/fast I'll just swap it out as they're all the same size). The motors are available form lots of different places on the net (but these happen to be in the UK and cheaper than most), used for all sorts from robotics, videocamera zoom/focus, door locking devices etc. Make sure you get 12V ones, as you can get the same size gearmotors rated for 3V or 6V

The bevel gears are 3mm bore and come from here: http://www.motionco.co.uk/pair-bevel-ge ... p-146.html they're £2.22 a pair including VAT. One of them needs to have the boss cut off the back flush with the gear, and reamed out to 1/8" bore to fit a standard 00 axle (not hard, I used a razor saw, file and a set of cutting broaches).

You also need to get a bag of bits from Alan Gibson (wheels, coupling rods, buffers, smokebox dart, crankpins, handrail knobs) Once I've built mine I'll put together instructions on my website and a list of bits. You're free to source things elsewhere of course. Mine will be using NER conical buffers, and there are circular rebates in the bufferbeams to fit the turned brass part at the base of Gibson's buffers. If your buffers are different, fill the rebate and use the 0.5mm hole in the buffer centres to line them up.

Perhaps I ought to leave the motor bracket in? If you did want to use a gearbox and mashima or whatever, the material cuts very easily with a razor saw and scalpel (for small parts), so it would be easy to remove the bracket. I've given the chassis a quick scrape off with the edge of a scalpel and rubbed it with some 800 grit sandpaper to remove any build lines, then sprayed it with Halfords filler primer, followed by halfords matt black, then a brushed coat of vallejo acrylic matt varnish. Once its dry I'll put wheels/bearings/motor together and hope to have it working tonight.

[Brack]

OK, so the chassis is working (please ignore my hideously bad soldering - it works!)

I've given the body a quick squirt of halfords lovely yellow filler primer, which a) highlights where the surface needs smoothing to lose the build lines/layering and b) makes the thing actually appear in photographs as something other than an nondescript shiny white blob.

I then decided to video it (on my stills camera) to show that it works. Firstly, I held the controller in one hadn, the camera in the other, hence a lot of wobbly camera, so I chopped those bits out. Secondly the audio was very stop start and out of sync, so I removed it. The motor/gearbox works well and runs smoothly and definitely slowly (turning the knob past 50 doesn't change the speed, just the volume!). However it is rather noisy. Since it was only running on a bit of test track on the keyboard shelf, and has no weight so the loco body is basically acting as a big sound box, I hope it'll reduce. The motor running on it's own isn't too noisy, but putting it in the chassis and engine has amplified it somewhat. I've heard worse, and it mostly gets bad when you go above shunting speeds.

anyway, the chassis looks like this:

still needs the brakes, sandpipes, and I'm going to knock up some guard irons from brass (printing them would've made them very fragile and quite thick, a few bits of filed brass strip is a much better solution).

Here it is working in all of it's unfocused glory. Once it gets some weight in things should be much better, but for a featherlight bit of plastic I'm pretty chuffed. (click the distorted picture and it should open the video)

[Horsetan]

Very ingenious. Certainly has potential to fill in for the late lamented Connoisseur 4mm etched kit.

[Brack]

Spent last night putting transfers on and varnishing the loco, and several people were very complimentary (and surprised) about it at Railex NE today - most people couldn't believe it was 3D printed, as there is no trace of layering on it. the boiler, smokebox and side tanks have lead in them, and on haulage trials it moved a 16 ton mineral wagon with my lead shot box balanced on top (total 986g on two axles in plastic RTR bearings). I could've fitted a second layer of lead in the tanks but I ran out of lead sheet! certainly haulage capacity isn't an issue.

It spent a little while on Contikits' stand and a little while being looked at and taken apart by various people. Please excuse the dust and fingerprints - the photos were taken after the exhibition!





I chose the number (982) at random about midnight last night from a list of locos which had been on the North Sunderland, and 'Luckily' Mr Dunn had a photo of No. 982 on his slideshow, so we could see that the blower valve and smokebox handrail I'd modelled were different to that particular example - moral of the story - always model to a photo! The lettering was also spaced further apart on the photo (the RM drawings show 4mm spacing, so thats what I went with and it was late at night). But with several batches of Y7s being built over 30 odd years there are lots of detail differences (compare photos of the two preserved ones and there are loads!).

I've made the 00 gauge version available on shapeways: http://www.shapeways.com/model/1264797/ ... r-ncb.html

You can either use the gearmotor and bevel gears I mentioned earlier in the thread (it runs quieter on ballasted track, but still a touch noisy, I've ordered the 51:1 version of the gearmotor to test, ought to be quieter than the 298:1 version it has in it!). If you would rather use a different gearbox/motor the distance between the frames is 10mm, and the motor bracket is easily cut away with a razor saw or scalpel shoudl it be in the way (I decided it was easier to leave it in and let people cut it out).

in the next couple of days I'll be putting instructions and photos of the build on my website (I don't believe in producing a kit without instructions, even though it is pretty straightforward).

If anyone wants an EM version, I need to know how wide the frames should be - the 00 one is 13mm over the frames, I'll just pull them out a little and put the EM version up on shapeways as well.

Now, can someone point me towards good 4mm drawings of a J79? (or send me some) I ought to be able to reuse half of the CAD so it shouldn't take so long this time...

[Tom F]

That is mightly impressive....could we be seeing the future of kit building?

[Brack]

thanks - as for the future, well, for an obscure prototype of around this size, it's probably the right way to do it (as you get bigger the cost becomes a significant factor). At least this way the chassis is pretty much slot the bearings in and screw in the motor, and the body comes square and correct with the holes for handrail knobs etc already in it so they shouldn't be wonky either. Pretty much anyone ought to be able to get a good model out of it with a little care.

I drew the CAD in spare time over about a week, and it needed no capital investment other than paying for the test print once it was done - less risk and quicker than making moulds/castings etc. I don't think I'd make a living doing this, but if its a prototype I want it probably doesn't take me any longer than it'd take to scratchbuild one.

The biggest problem with other 3D printed models I've seen is that few consider how to smooth the surface or bother to do it properly, so it stands out like a sore thumb and screams '3D print' at you. - Some pretty accomplished brass kitbuilders looked at this today and couldn't believe it was a print, which tells me I've done something right with it.

[Horsetan]

I absolutely approve of the use of bevel gears. They are the way to get a low-resistance drive, which helps with freer running.