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Hunslet 16" 0-6-0 ST


Nick Mitchell
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It has started to feel like I've got too many "almost complete" locos floating around my workbench, and not enough at the head-scratching "how am I going to do that?" stage.

 

Maybe it is because the fret is too long for the little drawer it has been trying to hide in, and the protruding edge of it keeps catching my eye, maybe not, but my thoughts have been turning towards this little etch I bought some time ago from Judith Edge Kits.

 

An industrial loco isn't part of any grand scheme - some of them are quite ungainly, but I've always liked the look of Hunslets.

Last night I made a start by ordering some 7.5mm driving wheels from Shop 3... So the Hunslet is now officially an active project, and certainly at the head-scratching stage.

I thought the Coal Tank was small, but in comparison this one is really tiny! I am working my way down from the 9F, and will hopefully end up one day with an L&Y Pug.

 

Anyway, to the kit, and my first thoughts on how to approach it.

A scan of the (exquisite) etch is below, so you can see what I'm up against.

 

1598059465_Judithedgeetchsmall.jpg.28f2c2476d078fdc7ea7b49b6639e2fe.jpg

 

The large square-ish piece to the top right is the boiler/firebox, intended to be rolled. Not quite etched through are slots to peel the bottom sides of the firebox out.

There is no provision for the tank other than the end formers and front end overlay. I think the 4mm version of the kit has a piece that needs rolling to shape. The radius at the bottom corners of the tank (in 2mm scale) is 0.75mm. I'm wodering if I could get away with using brass tube for the tank top and filing the bottom corners round.

 

At the top left of the etch are two sets of fold-up spacers - presumably one for OO and one for EM or P4. There are half-etched lines on the rear of the main frames for them to locate in, but obviously these will not facilitate split-frame construction.

I will use 6.5mm wide fold-up spacers (which neither of these are) and .25mm double-sided PCB in the Raithby tradition to set the frames 7mm apart.

 

I'm thinking that if I use some 8mm tube to repersent the bottom half of the boiler, I can attach it to the chassis via upward extensions of two of the fold-up spacers.

One spacer/support at the front can be tucked up against the rear of the smokebox, and one further back will represent the front of the firebox.

I can then rest a 7mm (Farish-style) coreless motor in the boiler tube, and arrange some sort of gear tower inside the firebox.

 

8mm is a tad under-scale for the boiler diameter, but it won't be too noticeable hidden under the tanks, as long as the bottom of the boiler is at the right height.

More importantly, 8mm will fit through the hole in the footplate, so that the main superstructure including the saddle tank and firebox sides can fit down over it.

I may get away with using part of the etched piece with the boiler bands on it as an overlay.

 

There was a 4mm scale drawing in the September 1972 Raiway Modeller (The kit came with a 2mm scale drawing, but when taking measurements, the bigger the better). I popped over to the Vintage Carriages Trust at Ingrow when I first go the etch, and picked up a copy.

Interestingly, a PECO Jubilee was advertised for sale for £8.99 in the magazine. According to an on-line historic inflation calculator, that would make it about £130 today - almost to the penny what you would expect to pay for the latest Farish Jubilee...

 

I have scanned part of the drawing and started playing about in Microsoft Word, overlaying shapes to represent gears etc. to check the feasibility of my ideas.

 

plan.png.b797e419637316493ec5f24165c645ee.png

 

The gears are 100DP, and what I already have in my spares box. A 21:1 worm and then 18:21 spur gears will give an overall reduction of 24.5:1.

I could use Mod 0.3 spur gears, and fit a 14:18 ratio in roughly the same space, giving a slightly better overall ratio of 27:1. This is what I have used in my Coal Tank, and the slow speed running on DCC is superb with this motor.

The green rectangle shows how a CT-Elektronik DCX77L will fit above the motor in the saddle tank. The dark yellow box shows how a tantalum chip capacitor or two might stand up in the bunker for Stay Alive.

 

The first task will be to extend the side frames upwards in the vicinity of the firebox.

 

If you fancy some prototype inspiration while you're stuck in lockdown, you can enjoy a virtual ride behind a 16" called Beatrice at Embsay:

https://youtu.be/9asoHjSKB1Y

I didn't make this video, but once you get past the dodgy introductions and incorrect captions, it is quite a nice ride. John Garwood is driving, and I'm firing.

The unusually delicate chuffing noise the engine makes is due to the Lempor blast pipe she's fitted with.

 

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Nick, have you looked at my Jubilee Pug build, which is a similar loco?  i added some of the parts I needed, mainly for the chassis, to an etch sheet I was doing, including the tank top, but I wished I had made the lower edges of that half etched to make forming them easier.  In the end I filed in inside down a good bit, but it was still a pig to bend and the results are not great.

 

Jim

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Fantastic! I was just looking at the 15” etch I have and wondering about it. To extend the frames, would it be a good idea to just start over, maybe with the etched ones as an overlay on top of a new piece that could include a bearing for the layshaft? Add a bit more rigidity too.

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8 minutes ago, 65179 said:

Looks like an interesting project Nick. How long before you find yourself building a whole colliery around it! 

 

Simon

You could say I'm digging a hole for myself here, couldn't you Simon? I'll get my coat...

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You beauty Nick, well done .  I have a 15" and a 16" ready to start on. Ive ordered name plates Ted and Archie for my two grandsons (I have an etch for a 14" as well but that can wait till, fingers crossed, any more grandchildren arrive!). I have 7mm wheels for mine though that's mainly because I had them in stock anyway.

I want mine to shunt the Colliery and Gasworks on the home layout. My Hudswell Clark saddle tank, 'Kimberly' has been the mainstay up to now but retro-fitting stay alive on a twenty year old loco isn't easy.

i too was planning to use a Farish style 7mm coreless but with 30:1 followed by 14/21 spur gears with a chip below the motor between the frames similar to the Midland half cabs I built recently which would give 45:1 overall but I would encroach into the cab more than your design  - albeit below window level so still clear in silhouette. I may well revisit this as your design is much neater and your coal tank runs beautifully. Being able to get the chip on top of the motor is also much easier than trying to shoehorn it around the axles, particularly with the extra wires for a stay alive.

I shall be following this thread closely and be shamelessly robbing all the good ideas that crop up.

 

more power to your elbow.

 

jerry

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3 hours ago, Caley Jim said:

Nick, have you looked at my Jubilee Pug build, which is a similar loco?  i added some of the parts I needed, mainly for the chassis, to an etch sheet I was doing, including the tank top, but I wished I had made the lower edges of that half etched to make forming them easier.  In the end I filed in inside down a good bit, but it was still a pig to bend and the results are not great.

 

Jim

Thanks Jim. I enjoyed following your build at the time, and have just finished re-reading the thread. Lots of good stuff in there. I imagine it will be a while until I need to worry about the saddle tank though.

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1 hour ago, Hendreladis said:

I just stuck a 2mm 03 diesel chassis under mine. It ain't pretty but you can finish the loco in a couple of days that way.

 

Great kit by the way Mike. I enjoyed putting it together. 

post-15858-0-86777600-1479667375.jpg

 

It might technically be wrong but it certainly looks right which is half the battle. Lovely job. Anyone going to volunteer to do some boiler fitting masters for casting - either turned or 3D

 

Jerry

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1 hour ago, queensquare said:

 

It might technically be wrong but it certainly looks right which is half the battle. Lovely job. Anyone going to volunteer to do some boiler fitting masters for casting - either turned or 3D

 

Jerry

 

Do you have the drawings? If I have the dimensions then feeding them into the computer to 3D is straightforward. Someone else would need to print them because I haven't given in to that temptation for a printer. 

 

 

Edited by richbrummitt
I've just looked three posts up - Doh!
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Nick,  I assume you have the CT decoder in your spares box, because they're becoming quite hard to find.   Otherwise its something larger - Zimo, D&H, Kuhn, ESU being the usual candidates to look at.

 

Lower boiler could be to scale diameter if its not a full semi-circle and still fit the opening.  

 

 

 

 

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5 hours ago, Hendreladis said:

I just stuck a 2mm 03 diesel chassis under mine. It ain't pretty but you can finish the loco in a couple of days that way.

 

Great kit by the way Mike. I enjoyed putting it together. 

post-15858-0-86777600-1479667375.jpg

That works reasonably well despite the incorrect wheelbase, body looks good too.

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I've had to fight with this a little more than I wanted since it's the first time I've done this kind of thing in this current 3D CAD package. Now I know a reasonable way to get this far.

image.png.5d4a3dc4694147b8f872f2de330729a3.png

 

I haven't scaled them yet they are just relative good size based on importing the GA pdf provided at around 400% so that any errors in tracing should be tiny once reduced to the final size. 

 

@queensquare Jerry, how would you like the bases? At the moment I've assumed that the hole for mounting will be the size of the base of the fitting i.e. they're cylindrical where you cannot see them.

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10 hours ago, richbrummitt said:

Like this.

 

 

 

I think this could be a good way to get a thin flange for the final model since thin bits are not very strong when printed in resin.

Hello Richard,

 

I'm impressed by what you've done. I think it might be useful if the underside of the base had the start of the filing line i.e. a slot included say 2mm wide and 0.5mm/ 1mm  deep, depending on the thickness of the base.

 

Nig H

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3 hours ago, Nig H said:

Hello Richard,

 

I'm impressed by what you've done. I think it might be useful if the underside of the base had the start of the filing line i.e. a slot included say 2mm wide and 0.5mm/ 1mm  deep, depending on the thickness of the base.

 

Nig H

 

Thanks Nigel,

 

I'm trying to work out how you avoid filing them completely and have a thin base. A larger hole in the top of the smokebox/tank is, I think, the answer but it needn't be quite as big as the diameter of the bottom of the flare. Maybe cut in about .5mm all around to give a small lip at the base to locate.

 

The base is probably very very thin. It's around 4.3mm at the moment but the models are also a few hundred mm diameter because I haven't scaled them yet. That will be the last job before handing them over to someone to arrange the manufacture.

 

Richard.

 

 

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Would the idea be to use the prints as masters for brass casting? Nick Tilston has done this for some of the recent N Brass range, and the results are very nice. The very edge of the flare on his L&Y chimney for example (which is nice and wide and easy to measure) is 0.25mm thick. It has a 1mm printed spigot before attachment to the sprue.

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On 19/04/2020 at 15:51, Nick Mitchell said:

Would the idea be to use the prints as masters for brass casting? Nick Tilston has done this for some of the recent N Brass range, and the results are very nice. The very edge of the flare on his L&Y chimney for example (which is nice and wide and easy to measure) is 0.25mm thick. It has a 1mm printed spigot before attachment to the sprue.

 

I have no personal need for hunslet boiler fittings but accepted the challenge. I make the chimney 5.57mm height measured from the very top of the smokebox. The flare then scales at 0.075mm thickness for 2mm/ft. I can ask Nick what is possible for you all. It will be interesting for me to follow this through, unless someone here wants to take it over?

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I've made a practical start by extending the frames.

 

Not wanting to let bits go to waste, I used a couple of the "OO" spacers, which were roughly the right sort of size, and attached then to the frames above the rear axle hole, using scraps of the etch frame as reinforcing pieces at either side.

 

This was done after the rear bearing had been soldered in and filed flush to the frame on the outside face, so I could line things up approximately. According to my plan, the axle with the worm wheel / 18T spur ear will be directly above the rear axle.

 

Fortunately, when opening out the axle holes to 2.5mm to accept frame bushes (they were etched approx. 1.8mm), there was just enough metal surrounding the hole.

 

Out of interest, the 2 tiny etched holes near the bottom edge of the frames are for locating pivots if you are installing compensating beams. I will use them as the fixing points for Simpson springs. 

 

IMG_0404.jpg.1cbc5242042cdc69027c439b74559eec.jpg

 

Having used the Association gear meshing/marking tool with 1/8" points to gauge the spacing for the 18 and 21 tooth spur gears, I swapped one of the points to a 1.5mm one in the tool. This allowed me to use the rear axle bearing as a pivot, and scribe an arc at the correct meshing centre of the other axle onto the frame extension.

 

IMG_0407.jpg.9b2e0d823c088891b50f159e81760c9b.jpg

 

Lining up the top edge of the frame against a horizontal line on my cutting mat, and sighting a vertical line through the centre of the bearing, I could line up a ruler against the same vertical line and scribe vertically to mark the centre of the new hole. The photo below shows the centre popped through the resulting cross-hair from the other side:

 

IMG_0409.jpg.49f7e67216b43622dc270abd3609508b.jpg

 

I then used my Association frame assembly jig to clamp the two frames together (flush outside faces touching), and held the assembly in my vice to drill through both frames at once. In the photo below I am about to start drilling, with a sacrificial bit of coffee stirrer on the vice jaw to drill into.

 

IMG_0412.jpg.831b5cb23db6380c3ff63922e74e332e.jpg

 

The hole was drilled undersize, then carefully opened out with a broach, one frame at a time. Holding it in my vice as shown below, I could clamp both parts of the frame to discourage them from pulling apart. Gently did it!

 

IMG_0413.jpg.7b6fb60b3eaa40d9ab2f0fd5fbcc6525.jpg

 

Somehow I managed to solder in the bearings without everything falling apart, and after filing them back flush to the outside of the frames, you can hardly see the join. I will need to remove a section of the cab floor to accommodate this new gear tower, but it will only intrude a couple of mm into dark recesses at the front the cab.

 

IMG_0414.jpg.6cd433d34846e5a9db6c36cbddecc64f.jpg

 

This last shot is rather cruel, and represents a very un-scientific attempt to see if the new holes were in the same place on both frames, buy threading through several lengths of axle steel and lining it up over the squares on my mat. The wonky photo doesn't make it clear, and I suppose I won't know for sure until I have erected the frames, but I think I am in the right ball-park.

 

IMG_0415.jpg.2c0c1273ef9f22131d30ffd58b802032.jpg

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1 minute ago, richbrummitt said:

I've discussed with Nick by email and he's up for casting some. None of his casting suppliers are working at the moment but I don't think any of you are in a rush. 

 

Excellent news Rich

 

Jerry

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