5"g Simplex steam loco build (hopefully)

[JCSteam]

I'm going to ask what I think will turn out to be an obvious answer.

On the quartering for the wheels, I can see the two pieces look the same height, is this correct? If so how do you determine the height of them is it half the radius of the wheel, to the outer flange?

 

[bazmak]

Its simple trig. You know the wheel height above the datum and the radius of the crank at 45o to it. simple 45o triangle has side in proportion 1-1-root2
so you can calculate the height of the crank centre - half dia and that gives a height in this case 1.372.So 2 spacers of that size acting like a sine bar posns
the wheels each at 45o

 

[pendlesteamer]

Simplex was my first engine and is now 28 years old, admittedly spending the middle 20 years in its storage box. Now running regularly again.
Would recommend you fit a pole reverser rather than the screw type as designed, much more user friendly and more prototypical for a shunter.
I also changed the regulator to a disc-in-tube type, far better than the screw type. If I was doing it now, I would also face the disc with ptfe.
One mod I might get round to is to fit a smaller capacity axle pump, I find that the bypass has to be fairly well open most of the time.
Another useful addition was to have a level gauge fitted to the rear of the LH side tank where it projects into the cab, you have a constant indication of remaining water.
Search "Simplex" in Engines to see mine.
Good luck with yours.

pendlesteamer

 

[wazrus]

Bazmak

Possibly, you're a firm supporter of Australian businesses: if so, then read no further....hmmm....
BA fasteners can be had, of course, at a price. Small fasteners generally can also be had, again, at a price, or I should say markup.
I've bought loads of small socket-head capscrews on Ebay, out of China, from a mob called Junter Hardware. I've got 'em down to 1.4 and 1.6mm., in a variety of lengths. I also bought some 2mm hex head screws while in Hong Kong some time ago and it wasn't a matter of the supplier pondering or scratching his head, it was very much "Certainly, sir. How many thousand would you like?". I've got nylock nuts at 1.6mm and round-head Phillips screws down to 0.8mm and while round heads mightn't be very useful on a live steamer, it's indicative of what's out there. All in stainless steel.
Hobson's - not sure whether they're Sydney or Melbourne, will also do 3mm hex heads in stainless, at a reasonable price. I'm in Sydney and one of the better nut and bolt suppliers has proved to be Raneve in Riverstone.
I've pretty much moved completely away from BA and any of the other 'imperials' and gone entirely to metric. I've 'replaced' British Standard Brass (26tpi) with 1mm pitch metric tackle and I've got a good suite of taps and dies, at that pitch, from 6mm to 38mm. Taps at 38mm are pretty hefty items and freight/postage can be an issue, but is, more often than not, subsidised out of China by you know who and is often free.
Unethical? Certainly. Effective? You betcha.
Wazrus

 

[bazmak]

thank you pendlesteamer for your informative post.Although i have a love of steam trains from my youth and know of the basic workings i am not very
knowledgeable and am just playing really to keep meep me occupied,whether i get get to steaming stage or just running on air i just dont know.Glad you are following this thread,any help and advice would be greatly appreciated
Thank you Wazrus on your info on fasteners.I am basially using a mix of what i can get hold of and have taps and dies etc.I make revamp fixing to suit looks etc as i get further on

 

[bazmak]

Made and fitted a few more bits.Not in any sequence but what i have in matl to hand and what can be finished and fitted.Every time i pickup the unit from one day to the next it seems stiifer.So i made a couple of knobs to fit the trailing axles and help to turn over the wheels and rods as i make and fit.This way
by adding items you get a feel for where things are binding.Also noted that
one of the crankpins is rotating.Light press fit was too light as i was worried about cracking the wheel castings.Lots of things to go back on and rectify/improve at the next strip down.Cylinders just arrived so starting them next

 

[wazrus]

Pendlesteamer's thoughts on regulators are interesting. Personally, I've used a poppet type regulator in a Sweet Pea -as per the words and music - and my next 'build' is a freelance job based on bits pinched from various designs.
Like Bazmak, I've had difficulty sourcing much of the specified material here in Oz, such that my wheels are all flame-cut from 20mm black bar. The wheels are quartered using parallel keyways. Frames are fettled from 76x12mm black bar and cylinders are from my own patterns, cast by a local foundry. Sweet Pea used steel wheels also, but a lot of machining produced counterweights etc., so much machining that my next loco, the freelancer, is an outside frame type, so the wheels aren't really 'on show' and as such, are just plain MS discs.
I'm a little surprised to see cast iron wheels without tyres??
Freelance has both twin pumps and will have an injector as well. Belt and braces! Too much water is a good thing....In fact, there are two pumps.
Freelancer is the biggest lump of steaming metal which I reckoned might stably ride 5 inch rails and is more like a mid-sized 7-1/4 incher than a 5. Haven't finished the boiler yet, but it'll be LP gas fired. Barrel is rolled by yours truly out of 4mm copper plate, as 170mm-odd copper tube is a bit hard to source. 5 inch Sweet Pea (named Lathyrus: freelance is Lathyrus Major) used 4mm copper boiler also to the words and music, but not very satisfactory words or music, to the extent I've scrapped it in favour of an LPG specific idea. All to AMBSC copper code.
Wazrus

 

[wazrus]

For Pendlesteamer and Bazmak
Attached - I think - are a few pikkies of The scrapped boiler from Sweet Pea (Lathyrus), beside the new boiler - or at least its barrel - for Lathyrus Major. There are also some pix of the chassis, no rods or valve gear. Valve gear will be Walshcaerts', a design pinched from Reeves' Aquila. I bought the plans for just the valve gear, as there didn't seem much point in re-inventing the gear. There's a strange-looking blue assembly at the rear of the chassis: this is an hydraulic brake. It's an external-contracting type, with friction material bearing onto an axle-mounted drum. With past experience of trying to stop a train with six hefty adults on board, something better than the Sweet Pea lashup or two size 10's buried in the gravel, had to be done. It, like most other bits, are works in progress. I've used twin axle-mounted boiler feed/transfer pumps and these don't use the usual bronze eccentrics, but have very narrow, sealed ball bearings instead. the balls need more space, which reduced the effective eccentric throw. To remedy the short stroke, I've used a 1:3 linkage, so the pump drives look a bit complicated in the pix. No apologies for the kaleidoscopic colour scheme. The colours are what I had available and anything looks better than rusty metal.
Wazrus

 

[pendlesteamer]

Would recommend you don't try and rely on loco brakes when passenger hauling, you need brakes on the riding trucks. Locos would tend to lock up and just slide. Our club passenger trucks have a mechanically operated disc brake on each bogie, if you have 8 to 12 passengers at up to 10mph you need serious brakes to dissipate that energy.
Cast iron wheels without tyres are probably 90% of our clubs locos. For an engine running say a couple of hours a week, wear is not an issue. Steel tyres have slightly better traction and I have put tyres on the drivers of my Midland Single because of that.
My thoughts re feed pumps is to have the loco as efficient as possible. Pumping water and discharging a high proportion through the bypass is wasting energy. I would like a pump that only just gains on boiler consumption with bypass shut. Top up when stationary or when required is by injector.
One "experiment" I tried on my Simplex was to have the axle pump discharging through a double coil of copper tube wound inside the smokebox wrapper before going to the boiler check valve. It does warm the feed slightly, but not sure if it makes much difference to efficiency.

Pendlesteamer

 

[bazmak]

Hi Pendlesteamer, your first name might be easier.Where are you from in Lancashire ? I too have thought about keying the wheels to the axle but if they are not correct the first time your stuffed.It would overcome the problem of the wheels twisting out of position when quartering and pressing on and of course the not quite correct press fit.But how many times would you have to take them apart ? Thought about getting them right then fitting a small grub screw from the front half and half on wheel and axle, but it wont look right
Your thoughts would be appreciated Regards Barry

 

[pendlesteamer]

Hi Barry
I live in the borough of Pendle which is just north of Burnley, and have had a lifelong involvement with steam hence the online handle. Spent a number of years as ships engineer mostly steam turbine plant, then even more years as boiler inspector around northern U.K. Now retired, best job ever!
As regards your wheels, many in our club use what we know as a French Key. Once your wheels are correctly positioned on thei axles, you drill half in the axle end and half in the wheel say 1/8 to 3/16 diameter with a depth of say three quarters the wheel thickness. You then press in a round dowel with a drop of loctite if necessary. When dressed off flush with the wheel face and painted they are barely noticeable. If you ever need to pull your wheels, a grub screw may have seized in; whereas the wheel will draw over the dowel.
Regards
Rodger

 

[wazrus]

For Pendlesteamer and Bazmak
I've seen many and varied methods of quartering drivers and parallel keys do it for me, every time. I use a very simple truly square lump of suitably bored mild steel, into which one axle is keyed. It's a simple matter to then rotate the assembly 90 degrees and machine the other. With reasonable attention to accuracy, it'd be hard to miss! Note that the assembly is held to the mill table, not in a mill vice.
The French key described: we used to call it a 'Scotch' key!
Brakes. Ah, brakes. There's another external-contracting hydraulic unit on my riding truck, two axles of which are linked with roller chain. One of my passenger trucks - a bogie vehicle - also has both axles on each bogie chain linked. The chain run on each is led over a mid-positioned sprocket, on the axle of which is 200mm brake disc, carrying a motor-cycle disc caliper. A motor-cycle master cylinder and flexible lines ensure that all 8 wheels brake together. It's possible to lock up all 8 wheels when loaded.
None of the braking I've used, though, will bring a loaded train to screaming halt. Not a lot is gained, as you say, by locking wheels, other than annoying flat spots.
For internal keyways, I use my own home made broaches. Cutting the mild steel drivers' keyways, while needing a few passes with the broach, is quite easy.
Wazrus

 

[pendlesteamer]

Hi Wazrus
Yes you are correct it should be Scotch Key or sometimes Dutch Key according Wikipedia.
Emergency stops are difficult with loaded trains as you say, it is imperative to keep a sharp lookout ahead especially when multiple trains are operating. We have had the occasional near miss and they are always due to lapses in attention when adjusting injectors or firing coal etc.
Regards
Rodger

 

[bazmak]

Thanks Rodger,for your info.Been to Burley many times for work and years ago
to watch Leeds.I always remember the crowd chanting (keep codding them Elder)
Well the cylinder set arrived and all checked out OK. Again i took the long way round.When i did the 3 cyl Heilan Lassie i did everything in the lathe on faceplt/angle.It was easy and the words and music came from dear old Curly
from 1947.Now i have the mill and the casting are much larger.For boring i
could use the mill but prefered to use the lathe.I deskinned and took a light cut
to all main faces ignoring dims but trying to get squareness to all faces
mainly for gripping in the chuck and use of datums.I then gripped in the 4 jaw and centraalised the cored hole before boring out/cleanup and faced the end
Mainly to check out the accuracy of the bore for parallel etc.Quite good
So i reversed,recentralised and bored and faced the other end to size.I then put in the mill and faced the first end to size. Now was the tricky bit,ie machining the 2 main faces to dim but more importantly parallel to the bore
Little bit of playing about and packing with feeler gauges but it was easy to measure from the face to the edge of the bore.Long way round but got there in the end

 

[bazmak]

Good progress on the cylinders.All the main faces/bores are finished to size
Bores are about 12 thou down.Reason being to allpw for a little honing/cleaning
and also to use std 1.5" dia stock for the pistons.Will assemble and make sure
everything turns over before maching steam passages etc.
Rather than using stud and nuts to hold down the steam chest i plan to use
hx sock cap screws partly recesses.This will give me a problem of keeping the chest in position when the fixings are removed.I have in mind to fit 2 no
csk fixings thru the steam chest only,with some of the fixings going thru everything and some only into the steam chest.As drawn there are no fixing dims just a note to say to posn to avoid steam passages etc which are drawn offcentre but not dimensioned,but i assume will be central to the piston bore
So will leave some fixings untill later when things become more clear and i
can maybe even things up purely for aesthetics.Better safe than sorry

 

[JCSteam]

Is the angle bracket in front of the leading wheel a tempory fixing? I imagine it is, is the slide for the pistons big end bolted to the rear of the cylinder?

 

[bazmak]

Yes the angle bracket was temporary to check fit and dims for the cross head etc. Length of slide bars is within 10 thou when i checked to the piston etc
All still temp bolted so should be able to finalize more accurately when i
make the piston/rod etc and check travel. Then its a strip down to free and
finalize the wheels and conn/coupling rods. Still a bit stiff. Mau have to tighten up the crank pins and may key the wheels/axles

 

[bazmak]

After a few more hours and in response to the above post i removed the temp brkts and fitted the partial machined cylinders and slide bars.Still stiff but turns freely by hand.Next to make the pistons and rods and check turnover before
a strip down to remedy all minor niggles and fit all the correct fixings etc

 

[10K Pete]

I've been following along from the start, Baz, and loving every minute. I've always want to build one like that and this thread may show me just how 'easy' it would be!

There's a problem: as the thread grows it's taking a long time for all the photos to load, and the current page isn't really visible until all the photos load! And the pics run off the right side...

The one image I just checked, the rear cylinder head in the mill on your own table, is 1200 x 726 in size. That's twice what I thought they should be????

Anyway, maybe someone smarter than me can figure out how to fix this.....:hDe:

Cheers!!

Pete

 

[wazrus]

Cylinders for my three creations so far have all been from varying styles of my own patterns. With these, I usually leave the steam chest in one piece with the cylinders and slice the chest off in a bandsaw, after driliing chest-to-cylinder stud holes. Cylinder(s) and chests are then carefully machined either in a shaper or mill, straight and parallel to bore and mounting face.
Bore finish is as advised by a friend who routinely machines hydraulic cylinders and parts and it was his contention that the rings/piston/packing would 'do the needful' over a short time and it was more important to have the bore parallel for its length, than mirror-finished. Rings are cast-iron, machined from a solid lump of cast rod.
Both cylinders were aligned together with a close-fitting steel bar through the bores and mounted on the mill table, using vee-blocks, for machining of the mounting faces. An angle plate held the block firmly and was also used for machining the ends.
It's pretty safe to say that my patterns allowed more 'meat' for machining and squaring than commercial offerings.
Wazrus