Building a 16mm Scale Live Steam Loco

[LisaP4]

As those who read the Early Risers thread in Wheeltappers will know, I've started putting together the materials needed to build a 16mm scale live steam loco. Construction of this will start once I've finished the coupling rods for my 5" gauge loco, so is probably a couple of weeks away still.

 

However as materials for this little loco have started to arrive, I thought I'd start the promised thread now, and will show pic's of the materials as they arrive, before any work commences.

 

I'm intending to sell the loco once finished, to supplement the crowdfunding campaign I have going to try to get a lathe big enough to finish my 5" gauge loco. Fortunately the little lathe I have will do fine for this small loco.

 

The plans I have come from Australian Model Engineering magazine about 10 years ago. The loco is an outside framed 0-4-0T, with 2 12mm bore x 20mm stroke cylinders, and a gas fired boiler. Being outside framed also means I can easily make the loco gauge-adjustable between 32mm and 45mm gauges, simply by attaching the wheels to the axles by means of grub screws.

 

Here's a loco to the same design that someone else built:

(photo from http://www.sandman.org.nz/home/grailway/GRail.php- go to the bottom of that page for some more pic's)

 

The first pic' of materials for this are some 1.5mm steel sheet for the chassis mainframes, and buffer beams; this I already have a fair amount of on hand, enough in fact to do the body work of a 4"/ft scale narrow gauge tender (which I have no need for). Plus 4 blank disks cut from some 45mm steel rod for the wheels.

 

 

More bits and pieces are expected to arrive next week, but as mentioned I likely won't start actually building till the week after that. Maybe, I may start turning the wheels sooner.

 

The first thing I'll likely do though, and probably before the 5" coupling rods are finished, is turn and harden some small steel buttons. These will greatly aid in filing round ends on the valve gear, when the time comes.

[hobbyhorse]

Sounds like an interesting project.

 

Simon

[DDolfelin]

Good to see - your father will be interested in progress i expect!

[Jock67B]

Good work Lisa, I've marked it 'follow this topic' so I get an alert when posts appear on your thread. I wish you the very best of luck with the build and I just know you're father will be proud of you on his better days.

Kind regards,

Jock.

[LisaP4]

Thanks, all.
Some more materials turned up in the post today.



From left to right:
8BA and 10BA steel bolts.
3 lengths of 6mm square brass, for frame stretchers.
5/32" brass rod, which I can't remember what it's for, but will no doubt stumble across at some point.
¼" brass hex, for glands.
1/16" stainless steel, for valve spindles.
3/32" and 1/8" steel rod, for valve gear pins, and assorted studs and such.
⅛" stainless steel, for piston rods.
5/32" steel hex, for threaded valve gear pins and such.
¼" steel rod for axles.
3/16" steel hex, for the crankpins.
½" brass rod, for various fittings.
¼"x¼"x1/16" brass angle, for bolting the motion plates to the frames.
1" brass rod, cylinder covers, and will also be used for some of the gas burner/tank parts later, as well as dome and chimney bases/caps.
⅜" and ½" brass hex, for main steam and exhaust pipes and fittings.

Also hiding around the workshop is plenty of plate offcuts for things such as cranks and flyweights, some brass flat bar for the steam chests and valves, and various sizes of bronze for bushes, and some aluminium flat bar for buffers/couplings.

If I haven't forgotten anything, then I should now have everything for the chassis other than some brass square rod for the cylinders, various O rings, and some grub screws to hold the wheels to the axles. None of which I've bought yet, thus why I don't have them.

The first tasks I'll do here will likely be to make some jigs for the cranks and flyweights, to ensure the crank throws are all the same, and parallel to the axles. Mostly doing this now, as I've currently got the 4 jaw chuck on the lathe, so may as well.

[LisaP4]

It begins!

 

I decided to ignore the above mentioned jig for the moment, and instead set about cutting the frames. Even at near-midnight this left me in a hot sweaty mess due to the heat and humidity here, so I think I'll stick to cutting one at a time. The cut wanders all over the place but I allowed for this when marking out, and will just file the frame to size - once both sides are cut and clamped (or bolted) together. This will also give two identical side frames, which is greatly desirable.

 

So here it is, the first part, one side frame with dodgy cutting. I've laid a ruler in place so you can get an idea of size. Also in the frame, is the midpoint handle for the hacksaw blade; this being how one makes a long cut without the saw's frame getting in the way. At the top of the frame is some 5mm thick steel, which is what I'll be cutting the cranks and flyweights out of.

 

Also, note the thick lines in the bottom left corner of the frame, I put this there when marking out to remind me where the confirmed square corner is, with two actually straight edges coming off it.

 

Once again, I miss having a bandsaw, but nonetheless we'll get there anyway.

[Jock67B]

Lisa,

That's hard but superb work with just a hand saw!

Kind regards,

Jock.

[LisaP4]

Thanks Jock, it's mostly the weather that makes it hard work though.

 

But I've finished cutting out the frames now anyway; though still need to cut out the (front and rear) footplates. So here they are in about the correct positions, leaning against some scrap:

 

Next task here will be to fully mark out one side frame, and drill the holes for the frame stretches in it. Then I'll use it as a jig for drilling the other side frame, so they can then be bolted together and filed to size, before drilling the other holes for axle bushes, cylinder mountings, etc. The buffer beams will be done similarly.

 

I'll likely make a drilling jig for the axle holes, so that later when I make the coupling rods I can use it for them and ensure all the holes are at the correct spacing.

 

I also need to make that crank drilling jig I mentioned previously, then start turning the frame stretchers. These are just some ¼" square brass, which need to be machined to all the same length, and drilled and tapped so the side frames and buffer beams can be bolted to them.

[LisaP4]

The side frames are now filed to size (complete with me melting into a sweaty puddle of goo in the process), and mostly drilled. I still need to make the jig for drilling the second axle hole, drill it, then open the axle holes and the steam/exhaust pipe clearance holes out to the finished sizes.

 

Despite showing BA bolts in a previous post, I've actually opted for M2 reduced head bolts; mostly because they arrived on time, so I didn't end up using the BA backups. You can see the rather nice 3mm hex head here, this scales to about 2¼" across the flats in 16mm scale, which is quite nice.

 

The buffer beams are still only rough cut, I'll do those when my arms have recovered from filing the side frames; I may have overdone the amount of material left on to make up for the wandering saw cuts. In the mean time, the jigs I keep talking about making, but not, need to be made.

[Mike Storey]

Outstanding aspiration - very best of luck with this! Especially as you appear to intend to make the pistons yourself. Will you attempt the boiler too or buy one?

 

Mike

[LisaP4]

Hi Mike, thanks.

 

I did consider buying a boiler from the likes of Roundhouse et al, until I saw the price; which is about twice the cost everything else combined. Which isn't that surprising really, but nonetheless I'll make the boiler myself. I have the boiler plans for this loco on hand, and it's a relatively simple design anyway; just a basic silver soldered copper pot with a single flue. I'll hydro test it to four times working pressure, so as to be sure it's good for the job.

[Mike Storey]

I presume you are a member of one of the socs like the Assoc of 16mm NG Modellers? (I am not sure who your Dad is, so this may be teaching you to suck eggs, but....) They can have your boiler pressure tested and certified, which will be essential if you do want to sell it at the end, and for you or someone to insure it if being used in the presence of third parties, like at an exhibition. Many apologies if you know all that already! I can see you are an engineer, not only of some considerable skill, but of experience already.

[LisaP4]

Mike, I'm not currently a member of any club or association. However the boiler will be built to a standard design that complies with the A.M.B.S.C. code part 3 (sub-miniature boilers), it will be hydraulic tested to 4 times working pressure, and accumulation tested once completed and fitted. This is all that is required for certification according to a number of boiler inspectors I've spoken with (who would likely do their own hydro and accumulation tests before granting a certificate). Additionally I'll have photographic evidence of the construction, demonstrating solder penetration of the parts; this is not generally necessary for such a small (and low pressure) boiler, but I'll have it on hand anyway, as I'm documenting the construction here.

 

As a side note, while compiling the code for sub-miniature boilers, several boilers of varying design and construction were tested to destruction; the documentation of that, makes for an interesting read.

 

Meanwhile, I worked at marking out the buffer beams for drilling today, no pic's as yet, as it's just a few scratches on some metal. In the process I did a bit of double checking on the coupler/buffer height, comparing against a couple of Brandbright wagons I have. Apparently a centre height of 1" above the rails is the norm; which is also as-drawn, so no changes needed.

 

I will however be using a different coupling to that on the drawings, so as to stick with the somewhat standard single buffer with hook design, which I'll turn from aluminium. I'm half tempted to spring these, as making the stock and head as separate parts is the easiest way to make them; thus springing is basically just a matter of turning to a sliding fit and adding a spring, rather than pressing/loctiting the two parts together. I'll have a bit more of a ponder over this.

 

A length of steel bar is currently sitting on the bench with which to make the much spoken of jigs, so they likely won't be too far away.

[DDolfelin]

Pleased to see so much progress!

 

If it were me I'd just have reached the realisation that I was holding the plans upside down.

[M Wright]

Hi, I have been building small scale locos for a long time. Have a look at my website to see what I make (www.wrightscale.co.uk ) Congratulations on your first scratch build. There are a lot of pitfalls on the learning curve and here are a couple you can avoid now.  Proceed no further before cutting out BOTH your connecting rods, roughly profile them at this stage and sweat them together.  Drill the through  by step drilling about 3mm for the axle centre distance.  Glue your frames together (superglue is excellent, when finished the bond is easily destroyed by the application  of heat, 200C)  Use your paired conecting rods as a drilling jig for your frame pair.  Secure the parts together with a pair of toolmaker's clamps ( tools that are worth buying  (3 inch size) for 16mm size projects) Drill through the stack with the 3mm drill, some kind of drillpress is really essential. Again a small chinese drill press/machine is cheap today. Recently I saw one in a supermarket for £37=50 - quite good enough for the first few projects.  If you have a machine make sure the job is held NOT BY YOUR HANDS. Drillling thin plate is dangerous. Always use something like a Mole wrench (self locking wrench) to hold the job on top of a block of wood.   If you have already drilled one hole in the chassis put your 3mm drill through this into the rods. Clamp the rod pair in the correct place (sight a centre scribed line through the second hole) and use another drill to do the second hole.  The loco will be an annoying failure if your axle centres do no exactly correspond with the connecting rod centres. Later identical rods will be essential to make quartering your cranks accurate and easy.  I think you mentioned cranks. To work the throw must be identical and all holes vertical.  Make the blanks, drill for axles in a drill press the MAKE A JIG.  This is a bit for thick plate  with a short piece of axle material inserted and loctited in.  When making the jig scribe for this hole and then using dividers scribe an arc the throw of your loco's cranks. Set you jig up in the drill press so that the point of a small centre drill is on the arc and lock in position.. Slip your embyonic crank over the axle stub, hold with mole and by eye arrange for the centre drill to be on the crank centre line, carefully drill a good centre.  Repeat with the othe crank blanks, then change the drill to the under ream size (5-8 thou under) for the chosen chankpin and drill them out in the press on the jig.  If you drill right through the jig plate you can ream in the drill press too.  Unplug the machine and turn it by hand is using a hand reamer.  Assemble wheels , cranks and crank pins to axles using Loctite retainer. Get the correct grade for the application and make sure your fits are correct. To work reliably Loctite needs about 1 thou clearance and the parts must be cleaned before assembly with lighter fluid or cellulose thinners or Loctite cleaner and ware clean surgical gloves for this.  Even a finger print has enough grease in it to ruin the joint (Also some people are easily sensitised to loctite) It is good practice when you have assembled to this stage to pin everything  to prevent a later failure of the Loctite joint. Almost done!

Boiler testing.  Having made many 100s of boilers and having to satisfy my business insurance DO NOT OVER PRESSURISE the boiler or gas tank when testing.  Doing so risks damage that only becomes obvious later in the life of the boiler/tank.  Copper boilers do not fail catastrophically they tear and vent unlike steel boilers that fail explosively. A copper boiler should be given at hydraulic test at TWICE working pressure and the pressure held for 30 minutes and steam tested to 1.5 working pressure,the safety valve being screwed down to achieve this then carefully adjusted back to the working pressure blow off.  My locos are tested to 140psi and the safety valves set for 65psi.

 

[PatB]

For anything compliant with the AMBSC Sub-Miniature Boiler Code 140 psi is 4x working pressure.

[LisaP4]

Hi, I have been building small scale locos for a long time. Have a look at my website to see what I make (www.wrightscale.co.uk ) Congratulations on your first scratch build. There are a lot of pitfalls on the learning curve and here are a couple you can avoid now.  Proceed no further before cutting out BOTH your connecting rods, roughly profile them at this stage and sweat them together.  Drill the through  by step drilling about 3mm for the axle centre distance.  Glue your frames together (superglue is excellent, when finished the bond is easily destroyed by the application  of heat, 200C)  Use your paired conecting rods as a drilling jig for your frame pair.  Secure the parts together with a pair of toolmaker's clamps ( tools that are worth buying  (3 inch size) for 16mm size projects) Drill through the stack with the 3mm drill, some kind of drillpress is really essential. Again a small chinese drill press/machine is cheap today. Recently I saw one in a supermarket for £37=50 - quite good enough for the first few projects.  If you have a machine make sure the job is held NOT BY YOUR HANDS. Drillling thin plate is dangerous. Always use something like a Mole wrench (self locking wrench) to hold the job on top of a block of wood.   If you have already drilled one hole in the chassis put your 3mm drill through this into the rods. Clamp the rod pair in the correct place (sight a centre scribed line through the second hole) and use another drill to do the second hole.  The loco will be an annoying failure if your axle centres do no exactly correspond with the connecting rod centres. Later identical rods will be essential to make quartering your cranks accurate and easy.  I think you mentioned cranks. To work the throw must be identical and all holes vertical.  Make the blanks, drill for axles in a drill press the MAKE A JIG.  This is a bit for thick plate  with a short piece of axle material inserted and loctited in.  When making the jig scribe for this hole and then using dividers scribe an arc the throw of your loco's cranks. Set you jig up in the drill press so that the point of a small centre drill is on the arc and lock in position.. Slip your embyonic crank over the axle stub, hold with mole and by eye arrange for the centre drill to be on the crank centre line, carefully drill a good centre.  Repeat with the othe crank blanks, then change the drill to the under ream size (5-8 thou under) for the chosen chankpin and drill them out in the press on the jig.  If you drill right through the jig plate you can ream in the drill press too.  Unplug the machine and turn it by hand is using a hand reamer.  Assemble wheels , cranks and crank pins to axles using Loctite retainer. Get the correct grade for the application and make sure your fits are correct. To work reliably Loctite needs about 1 thou clearance and the parts must be cleaned before assembly with lighter fluid or cellulose thinners or Loctite cleaner and ware clean surgical gloves for this.  Even a finger print has enough grease in it to ruin the joint (Also some people are easily sensitised to loctite) It is good practice when you have assembled to this stage to pin everything  to prevent a later failure of the Loctite joint. Almost done!

Boiler testing.  Having made many 100s of boilers and having to satisfy my business insurance DO NOT OVER PRESSURISE the boiler or gas tank when testing.  Doing so risks damage that only becomes obvious later in the life of the boiler/tank.  Copper boilers do not fail catastrophically they tear and vent unlike steel boilers that fail explosively. A copper boiler should be given at hydraulic test at TWICE working pressure and the pressure held for 30 minutes and steam tested to 1.5 working pressure,the safety valve being screwed down to achieve this then carefully adjusted back to the working pressure blow off.  My locos are tested to 140psi and the safety valves set for 65psi.

Yes I have a pedestal drill, yes I'm using loctite, yes I'll use their cleaner which I also have, yes I've used it before, yes I'm making a jig for the cranks as previously stated several times. Yes I know how copper boilers tend to fail, did you see the link I posted? The Australian boiler codes are somewhat stricter than what you can get away with in the UK, I'll be staying under 30psi, this means, as PatB suggested, your 140psi is more than 4 times the intended working pressure, I won't be going that high. This isn't my first boiler. I know about the coupling rods being used to drill the frames, in 5" and 7¼" gauges I've always used adjustable rods to set what works then as a drilling jig for the actual coupling rods; this time I won't use either method. Instead I'm opting to create a drilling jig that can be used for both the frames and the rods, as previously stated. Thanks for your thoughts though.

 

As today was relatively cool, I decided to get the buffer beams done, this was mostly just heaps of filing, again. The hole for the coupling/buffer was left small, I'll open it up once the buffers are made. The fancy curved cutouts in the bottom corners were made with the beams bolted together and clamped in the vice, then I hacksawed the most of it out, attacked it with the mini drill, and finished by draw filing with a half round file.

The pic' show the buffer beams, a Brandbright buffer/coupling sitting on one just to see how it looks; I'll be using this as a guide to make my own, the aluminium bar for which is also shown.

 

I must get on with making the jigs next, as they're holding up the side frames.

Also, apparently Brandbright is closing down (or pretty much have closed, other than filling existing orders), this is a shame as they had quite a decent range; hopefully someone will pick it up and continue producing their range, as intimated on their website.

[Happy Hippo]

Mike, I'm not currently a member of any club or association. However the boiler will be built to a standard design that complies with the A.M.B.S.C. code part 3 (sub-miniature boilers), it will be hydraulic tested to 4 times working pressure, and accumulation tested once completed and fitted. 

Lisa,

 

Don't over stress your boiler prior to a first firing.

 

2 x wp is the norm for a new boiler and 1.5 x wp for subsequent tests.

 

edit: Just seen Malcolm's post regarding this.  sorry for the duplication.

[Grasshopper John]

I'm also following your build Lisa as I'm new to the Hobby ( friends gave me the Grasshopper name ) looking forward to seeing your progress, I doubt very much I will be able to give any advice though

 

Grasshopper John.

[M Wright]

Hi, sorry for my post.  I do not want to teach my grandmother how to suck eggs.  You clearly have everything under control.  Pity you are not closer, I got a lovely newish large lathe this year - an Emcomat 17S to finish one of my" relaxing" projects - finishing a 10 1/4" gauge half size narrow gauge loco.  Very unexpectedly I found it lost on a rarely visited page on E-bay! I wish you luck of your venture to fund your Lathe. All the best.

[LisaP4]

M Wright, no problem, and thanks. I keep a bit of an eye on ebay and gumtree, but so far everything I've seen near-ish has been either at (or above!) new price, or cheap for obvious reasons. 10¼" gauge is a nice size, my dad would always have liked a 10¼" loco; he did nearly get one about 20 years ago, but the seller pulled out at the last moment, afaik the loco has been rusting away in a shipping container since.

 

Well I made one of the two jigs I need to make (at least for now, there'll likely be more later), this is for drilling the cranks. A broken 5mm drill fits through the axle hole in the crank, and the crankpin hole can be drilled repeatedly in the right place. The crankpin will be threaded into the crank, thus the hole is rather small as it's the tapping size for M2.

Ignore the rusty drilling table, by-product of it being rarely used for a the past few years. I still need to make the axle hole drilling jig, which I'll probably do soon after posting this.

 

Meanwhile, this afternoon I messed about with 2D CAD a bit (3D does my head in), to work out the buffer/coupling. This is aluminium for the for the head/shank and body, with some brass rod for the coupling hook/pin. The hook also being what holds the head into the body, it occurred to me that if I slotted the whole in the buffer shank it would allow for back/forth movement without allowing the head to rotate, thus potentially allowing for springing the buffer head. As designed it uses a Meccano spring (reproductions of which are available cheaply off ebay, plus I can pinch a couple out of the Meccano box). To make it unsprung one would just not slot the hole where the pin passes through the shank. Whether I'll spring or not I've not yet decided.

Note the 4 fixing holes on the rectangular back of the stock/body, as opposed to the usual method of one screw in the back. Some of the holes are perhaps a little unclear if you don't know what you're looking at, I've yet to work out how to draw hatches in CAD.

[DDolfelin]

You're steaming along, Lisa.

So will this model in short order at this rate of progress!

[Jock67B]

Lisa,

I like the coupling drawings, looks good and simple, which normally means it will work well. I have a feeling this thread is going to get exciting,

Kind regards,

Jock.

[Happy Hippo]

Lisa,

 

Which CAD package are you working with?

 

There is usually a hatch command.  without referring to my manuals there are usually two commands:  Area and Path.

 

Area will hatch anything enclosed space. ie  Draw a rectangle.  then put a circle in the centre.  Using the area hatch command put the mouse somewhere inside the rectangle and outside of the circle.  when you press enter, the rectangle should become hatched, but the circle will remain clear.

 

Path hatching is where you have to define the edge of the hatch. You probably won't need this as it is a bit more difficult to master (well I found it difficult)

 

Before I found it I used to place in a 45 degree line and then use a parallel command many times over to create the hatch, then the trim command tidy it all up to achieve hatching.

[LisaP4]

Richard, it's just librecad (http://librecad.org/), which is fine for my needs, and saves having a stack of scribbled on envelopes cluttering my already messy desk.

I've only used it a couple of times, so I'll get the feel of it eventually. I did have some big 3D thing a while back, can't remember what it was though, think I only used it once.

 

Jock, I don't know about exciting, but it's a bit of fun to work on, and hopefully to watch.

 

DD, I try to do a bit every day, which isn't always possible, but hopefully will mean things progress steadily.