Lady Stephanie Pumping Engine

[uuu]

Those perspex panels will give a lovely view, to diagnose if things go wrong underneath.  But is there any way of getting in to fix things, without taking the whole thing apart?

Wilf

[Zephyrin]

On my “Vulcan” engine, I made a small door in the wooden base... and during exhibitions, many people want to turn the small handle to open it, but there is only the water pump visible under the base of the engine, no secret mechanisms!
A transparent window would have been nice too!

[springcrocus]

Crankshaft

I made the crank arms first, cutting to length, then drilling and reaming the holes for the shaft and the crank pin. I roughed out the basic shape first, including removing the waste from the waist. The 2.5mm drill under the 5mm rod brings them up level.



Then I finished the outer form on the rotary table, mounting each end on a stub mandrel. The drawing shows sharp corners at the roots of the waist but I've chosen to make the more traditional shape.



I'm going to silver-solder the arms to the crankshaft and crankpin and then cut the middle bit out. The crankpin is shouldered each end to fix the 10mm gap accurately. I set the position along the crankshaft but wanted to check that it looked right when assembled first.



The soldering went well but I managed to get some on the crankpin and needed to polish it off. Because I don't have centres in the ends of the crankpin, I had to find a way to spin it in the lathe because my 6" 4-jaw chuck alone wouldn't hold it. I used a collet holder in the end (and had clenched buttocks throughout). The centre-indicator was just to get a rough guide.



The eccentric and the governor pulley were made next, the pulley in a single operation and the eccentric by starting with a billet machined all round to the maximum dimensions along with the groove, then drilling and reaming the offset bore on the mill and finally mounting it to a mandrel to machine the two bosses. No process pictures for these, just the finished items.



And, finally, all assembled into the bearings and tested for clearance. I need to make a thin bronze spacer to fit between the eccentric and the rear bearing to take up the end-float but, otherwise, this bit is finished.



I suppose I will have to get on and do the flywheel next.

Regards, Steve

[springcrocus]

Changed my mind about the flywheel, a job for later.

Crank Connecting Rod

I've made the crank connecting rod in three parts, the main stem so that I could turn it between centres and the two ends, one screwed in and one pressed in. I set the compound slide over to about 2° and turned the stem to half-way, then turned the stem round and did the same on the other end followed by blending in with emery cloth. The top fork had all the fancy turning put on it and then the two parts were screwed together with a short length of M5 all-thread.



For the other end, I started by making the decorative part first, using a large radius form tool to create the curve.



Then I transferred the bar to a square collet block and milled the rectangular lower section.



Then it was back to the lathe and parted off to length.



For the bearing, I milled up a pair of bronze blocks 10mm thick with an 8mm groove milled round three sides for the strap. The strap was made from 1mm thick mild steel and folded for a tight fit around the blocks.



After drilling the strap-fixing holes, the parts were clamped together with M3 screws. Then it was flipped sideways and the bearing hole drilled and reamed 8mm diameter. I haven't bothered to try and create the rounded shape at the bottom because, for static display, the crank will be positioned to hide that feature.



One thing of interest is how Julius has designed the coupling at the top. As drawn, assembly and, particularly, disassembly would be somewhat awkward.



Anyway, I've chosen to use a bronze clevis pin with a bronze collar for the upper coupling even though the more common method would be a steel pin and bronze bushes.



Regards, Steve

[Jasonb]

It would go together. Offer up the clevis without the bearings and then put the pivot in place. Being 6mm dia it will easily fit through the 7.5mm bearing holes. Fit bearings and do up your nuts.

[springcrocus]

Governor Drive

I've made the pillar that supports the governor mechanism from some spare cast iron that I had in stock. I turned the locating spigot on the bottom first, then held on the spigot with centre support to machine the outer profile.



A pair of simple bronze bearings were made and pressed into either end, followed by line-reaming to make the shaft a nice fit. Here it is fitted to the platform but without the bearings, I've just noticed.



The parts underneath the platform were made next with the pulley stand being made from some 1mm sheet steel, the basic shape cut and the feet mounting holes drilled.



Then it was folded and clamped around a piece of 10mm MDF so that the pivot pin holes could be drilled in line. The vice is just gripping the lower leaf.



The other support was bent up from the same material and all the other relevant parts made. This was more like assembling a Meccano structure with it's spindles, gears and pulley wheels.



This is the view from the rear. I will dimple the shafts and shorten all the M2 grubscrews before final assembly.



Regards, Steve

[springcrocus]

Pump Body

The pump body below the platform looks an interesting part to build, comprising three sections joined by angled pipework. The intake is to the side of the structure and the outlet is to the front.



The main body has a bulbous section which would be a doddle to make on a CNC lathe but, in the old days (when I was a lad  ), before ball-turners and copy-turning were common aids, a form tool would have been made to plunge-cut the shape. So I made this first.

Starting with a section of ground flat stock (O1 oil-hardening tool steel), I first squared off the front with the plate set at about 5° in the milling vice.



The drawing shows the bulb to have a diameter of 32mm so the boring head was pre-set to that size.



The stem is shown as 20mm diameter either side so a dozen plunge cuts at half-a-mil DOC were taken to leave the finished form.



The tool was then trimmed down to a usable size and hardened by heating to cherry-red and plunging into cold water. A light touch on the side of a fine grinding wheel to top-dress the tool and it's ready to cut. I don't bother tempering tools when they are for cutting brass - personal choice that some will disagree with, I'm sure.



First op was to face and rough turn the o/d to 34mm, leaving 6mm thickness up the flange end. Then it was reversed in the chuck, faced to length and the flange and locating spigot finish-turned. The bore was also drilled and reamed 10mm diameter. Over on the mill, the six mounting holes were drilled 3.3mm diameter and the four gland cap holes drilled and tapped M3.



Then it was back to the lathe and the workpiece mounted on a 10mm diameter mandrel. The first job was to turn the lower section to 20mm diameter for about 8mm length.



A radius tool was used to machine the rear section to the same diameter and finish the flange to 4mm thickness.



The form tool was set up and the bulbous section of the pump body formed. Part-way through, I had to centre-drill the mandrel and provide centre support, and the plunge cut had to be rocked gently side-to-side to get a nice cut but, other than that, it all went suprisingly well.



And to finish this section of the pump, the body was returned to the mill and the flats for the pipe-mounting positions milled to size. The cross-hole was also drilled at this time. Using pins in the drilled holes made it easy to get the two flats square to each other.



That's as far as I can go with this at the moment, I need to make the other components and then solder it all together.

Regards, steve

[Michael S.]

This all looks very good. The parts were professionally manufactured.

Best regards, Michael

[EricB]

Great work! I really like how you setup for the pump body.

Eric

[springcrocus]

Michael, Eric, thank you both for your continued interest in this build. Not much done last week due to decorating.

Pump Valves

The pump assembly is shown as a fully-soldered affair but I have chosen to solder each of the valves separately and bolt them to the pump body. There is too great a risk of passageways becoming blocked with stray solder and no means of cleaning them out.

The outlet valve was made from a block of bronze but only because I didn't have a suitable chunk of brass. After machining the outside dimensions to size, the various holes were drilled, tapped or reamed as appropriate.



Rather than make a fixture for the rotary table, I decided to use a radius cutter to machine the rounded ends. This is just a cheap router bit but perfectly OK for machining brass.



Since I was already making various M12 x 1 fittings, I also made a mandrel and screwed the valve to it. The extended valve section was then turned to the 18mm diameter specified. The inlet valve is a simple cylinder and I didn't bother taking any pictures of that.



The two angled pipes were made next, starting with a pair of flanges turned from brass bar and parted off 4mm long. These were held in a small chuck, using soft jaws, which was then gripped in a tilt-and-turn vice. Alignment of each part was by eye alone.



A 12mm hole was cut in each, staring with a 4mm slot drill and working up in 2mm increments. The two parts are at different angles so each was completed separately. With the vice level, the fixing holes were drilled 2mm diameter to accomodate 10BA screws (because I have loads of them!)



Two pieces of 1/2" brass bar were skimmed to 12mm diameter and cut off overlong to allow for soldering and final shaping of the ends. A solder ring was rested over the short protrusion and heat applied only to the other side of the flange.



The two sections were then held in the vice and the backs skimmed to just clean the back faces. Packing was used to lift the sections to avoid the ring of solder on the other side, and a stub of 5mm material placed in the hole to prevent crushing of the pipe. After silver-soldering, the brass is soft as putty.



I felt the best way to shape the ends was to bolt them to the pump body and use the boring head to form the ends. And the best way to mount the pump body was to bolt it to the underside of the cylinder mounting frame. Here's how the setup looked.



I think that'll do for now, you'll all get bored if it gets too windy.

Regards, Steve

[Kim]

It's really starting to take shape! 

Great set of operations to get there too. Thanks for sharing your process.

Kim

[EricB]

 

[samc88]

Lovely work Steve, that looks brilliant

[springcrocus]

Thanks, Guys. 

Pump Valves cont.

This is another picture of how the pump gets assembled and better shows the difference in the two angled pipes. I still need to make the inlet connection for the bottom it's valve.



Because I have already soldered the flange to the pipe, I need to be careful not to disturb this joint whilst making the connection to the valve body. I'm using two clamps here for a dual purpose, to hold the pipe in place and to act as a heat sink to keep that end as cool as possible. A solder ring sits astride the pipe and heating was done from the underside only. It took a little longer than expected but, the moment the solder melted, I removed the heat and let conduction finish the job.



Same rules applied for the other valve, soldering the pipe to the valve first, cleaning up in the pickle, then soldering the inlet port afterwards. Again, careful application of heat to get it just hot enough to melt the new solder without melting the ealier joints. Afterwards, each pipe was drilled through into the body.



The next picture shows my modification to the pump body. Because of the angle of the pipe, I had to go for three fixing screws whereas the shallower angle of the outlet valve on the right allowed me to use four screws. I also cut a recess for an "O" ring rather than use a gasket. It also shows that the solder joints have come out quite successfully.



So this is the full collection of parts for the main assembly and, this time, the components are in the correct orientation. The pressure bottle and assocciated parts are made but attach afterward through the platform. I will use silicon nitride balls to seal the valves but they haven't arrived yet.



This is a picture of the fully-assembled pump mechanism, temporarily attached to the cylinder mounting frame.



One of the pump assembled under the platform with the cylinder above...



...and, finally, an overview showing all the parts made to date.



That's it for a few weeks. I need to get a small boat boiler built for one of our club members and I want to finish off a "Tich" loco that Wilf and I built the boiler for. It just needs the plumbing done prior to getting it's steam test and a little bit of platework.

Sam, you've got a Tich haven't you? Did you get it finished?

Regards, Steve

[samc88]

Sam, you've got a Tich haven't you? Did you get it finished?

Regards, Steve

Not yet, I have made a few bits this year for it but I've not done much for a while with doing the Ransomes engine. It is looking at me on the workbench awaiting motivation