First, a few photos of what was supplied.

The supplied castings were of excellent quality with no inclusions or blowholes. A few of them had even been machined to provide starting faces and the baseplate had been ground both top and bottom.

The documentation was pretty comprehensive, drawings, parts lists, drawing lists and machining advice. What more could you need?

Starting on the baseplate

After a great deal of studying the drawings, I decided to start on the baseplate. I converted all the hole positions to co-ordinates taking the vertical centre line as reference. There are only 8 holes to be drilled and tapped M4, but accuracy is all important.

The baseplate on the mill/drill table. Note my home made tapping device to get the threads vertical.

Working on the cylinder

Working out just where the bore centre should be is a bit of a nightmare. You can't rely on the cast-in hole, it could be anywhere. I made up a wooden core and jammed it into the cylinder, then, using my laser centre finder on the mill/drill table, found what I hoped would be the centre. I made a small hole with a center drill, to help me align the casting in the lathe.

Setting up for boring

I've had this lathe for about 10 years and this is the first time I've used the vertical slide. This shows the cylinder mounted ready for boring. First step, drill succeedingly larger holes in the wooden plug, then push out what remains. Then you can get on with the boring bit!

A little tip, born of experience; make a note of the setting of the crosslide and vertical slide dials. They easily get knocked.

Boring the cylinder

Boring the cylinder is fairly straightforward. I just took small cuts ( 0.2mm ) until I got close to finished size and then took smaller ones. Even taking care while boring, the finish I got wasn't very good but a few minutes with a hone soon sorted that.

The next job wasn't very interesting, just trimming to length in the lathe with the cylinder held in the 4 jaw chuck.

Drilling various holes in the cylinder

Several drilling jobs that require accuracy. The flange holes at either end have to be drilled and then tapped M4. I would normally use my DRO for drilling a ring of holes but on this occasion the DRO decided to play up, so I had to do it the hard way. Similarly, the holes for the exhaust flange had to be marked out on the surface plate before being drilled. The holes for the drain cocks were done freehand as accuracy here is not too Important.

Milling the steam ports

I had marked out the port face on the surface plate but used the DRO to accurately position the milling cutter. The marking out was really just for reassurance! This is a delicate job as the ports are only 3mm or 2.5mm across. I pre-drilled to get rid of a lot of metal, then used a 3mm slot drill for the middle port, taking several shallow cuts to get the desired 4.5mm depth. I used a 2mm slot drill for the outer ports,taking care not to go too fast on the feed.

After the milling there are 4 holes to be drilled and tapped for the steam chest and then 2 holes to be drilled from the outer ends of the cylinder to the steam ports. These are drilled blind at 45 degrees. It's a relief to see the chips come out of the port!

Machining the crosshead guide

I had previously turned a mandrel to hold the crosshead guide and had glued it in place. The guide had been supplied with the feet pre-machined so all I had to do was trim it to length and machine a boss to fit the cylinder then turn the outer diameter to match the cylinder.

Milling the crosshead guide feet

The crosshead guide feet are anything but rectangular and needed a good bit removed from either side. I set the casting up on the mill table and used the mandrel centre as a reference. I also drilled the mounting holes.

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Drilling the crosshead guide flange

I cut off the mandrel at the same length as the feet and mounted it on the milling table feet down, aking sure it was square to the table. I used the mandrel centre as reference and drilled the 4 flange bolt holes. There are also 2 mounting holes for the reversing gear. When the drilling is complete there is one little job left to do. Remove the mandrel. As it was tea time when I finished drilling, I asked my wife to leave the oven on, and popped the crosshead guide in at about 210 deg.c. After tea, I took it straight into the workshop ( wearing my leather welding gloves ). One sharp clout with a hammer and punch saw the mandrel on the concrete floor, where it stayed overnight, cooling. I thought I might have a problem removing the glue residue, but all that was left was a little white powder which easily dusted off.

Machining the distance pieces

The distance pieces are in effect extension legs for the crosshead guide. Made of cast iron, they have to be machined so that they stand 4 degrees off vertical. Not a problem, just set them up on the milling machine and side mill them. Easy, if you have a digital angle gauge!

This really does make the job easy and if you haven't already got a digital angle gauge, I would thoroughly recommend one.

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Machining the crosshead

This is a fairly straightforward turning operation, followed by a session in the milling machine to flatten off the two sides and form the slot for the connecting rod.

The finished crosshead

Machining the crankdisc

This is just a disc with an offset boss. I pop marked the boss centre and the crankpin centre and set up in the 4 jaw with the boss in the centre. I turned down the outside and the boss, drilled and tapped it, and parted off. I drilled and tapped the crankpin end in the drilling machine and then used the good old fashioned method of hacksaw and file.

The finished shaft and crank

Machining the connecting rod

This should have been an easy job, just take down the ends to size and drill a couple of holes. I measured up the casting and decided how much to take off and how big a packing piece I needed. All went well and I milled both sides to size. Then for the drilling. The little end went well, but at the big end the drill decided to snatch and pulled the workpiece out of the clamp and drilled a hole at a very jaunty angle!

You can see how badly damaged the con rod was, but it was recoverable. I found a bit of scrap brass rod, a good fit in the hole and cut it off slightly over length. I then hammered it home, trying as best I could to fill the hole. Then a bit of silver soldering and the repair was a good 'un.

The repaired con rod, ready for a good clean

Machining the steam chest

First of all I set the casting in the 4 jaw and bored the holes for the glands and tapped them. No photos of this, it's a pretty simple job and needs little explanation. I then set up in the milling machine to bring the sides and faces to size.

Machining the eccentric straps

The first job is to bring the castings to the correct thickness. I mounted the casting in the 4 jaw. (Centring is not too important so long as its somewhere near, any turning marks will be cleaned up later.) Take off half the waste from each side and you're done.

After drilling for the fastening bolts and the link rod, the casting can be cut in two. Some might do this with a hacksaw, but I prefer to use a slitting saw. Ignore the scribed lines on the casting, I was trying to get an idea of the finished size. I cut at a point halfway down the flange. This is followed by a little bit of milling to bring the castings to finished size.

To make it easier to tap the bolt holes straight, I drilled the top half to clearance size and then mounted both halves in the vice, taking care to align them. This allows you to use the top half of the flange as a guide for tapping the bottom half. Yes, I know that the tap doesn't look vertical, but believe me, it is!

Obviously, you have to do all the above jobs twice, as there are two eccentrics. I always try to identify the two parts of each eccentric - mine are never the same! You can see I've written on them with a felt tip pen. After this I will mark each part with one ( or two ) pop marks in places were it won't be too obvious.

The last job is to bore out the holes for the eccentric discs. The large piece of packing is to ensure that I dont bore the chuck jaws!

I haven't taken any photos of the eccentric discs. These are just steel discs with shoulders and an off center hole. They are held to the shaft by a grub screw through the main part of the disc.

Machining the large flywheel

There are two flywheels and this is the large one. (The small one is used as the 'output pulley'.)

This is a big heavy lump of cast iron and as supplied, has two bosses, neither of which is perfectly parallel. This is why it is mounted in the lathe using tailstock support - I had visions (nightmares) of it flying around the workshop! Once the boss is machined and the wheel itself trimmed to size on that side, it can be reversed in the 3 jaw chuck and a decent grip can be had. Then the other side can be trimmed to size, the outer diameter taken down and the other boss cut off and trimmed. It's worth a bit of patience now in trying to get a good finish to the outer rim; it is possible to get a good polish on cast iron, but only if you put the work in!

Machining the bearing pedestals

The boss on the top of the pedestal was supposed to be 6mm finished diameter. Of my 2 pedestals, one was 8mm, the other just over 6. This was the ideal opportunity to bring them both to size and to form a reference point for the other holes.

After turning, each pedestal was mounted in the milling machine to drill the other holes and milled to provide flat spots for the bolts. The pedestals were then split horizontally and brought to correct size.

After tapping, the parts were bolted together and mounted in the 4 jaw ready for drilling and reaming to size.

The first trial assembly

I don't know about you, but having got this far and put in all this work, I'm just dying to find out if it all fits together.So here's the result.

Front View

Rear View

Well, the first thing I learned from this excercise was that the distance pieces ( the leg extensions ) weren't actually parallel and this caused the crosshead guide to rock slightly. The error was only about 0.2 mm, but needed to be sorted out. I mounted the base with distance pieces attached on the milling machine and gave it a quick trim.

The observant among you will have noticed the lack of a cylinder head and the piston protruding from the top of the cylinder. The piston rod turned out to be about 10 mm too long; a fault easily rectified.

You can also see that I have already started the long and tedious job of polishing the crosshead guide. This will look far better on the finished model if it is polished rather than painted. Polishing all the parts is a big task and, if I try to do it all after finishing all the parts, I find it a very tedious task indeed. It is much easier to do a little on each part as it is machined, then at the end all you need to concentrate on is final fitting and painting.

Machining the valve rod knuckles

The first stage - machining an offset boss on a square bar

As there are two eccentrics driving the reversing mechanism, so there are two valve rod knuckles each attaching to the link plate. They are offset by half the distance between the eccentrics.

Reducing the thickness

Forming the slot for the link plate

The finished pair of knuckles

The Stephenson Reversing Mechanism

The link plate being milled on the rotary table

I started by drilling the three mounting holes and then drilled two holes at either end of the slot and milled between them. I also milled the top and bottom edges of the link. After that it was a hacksaw and file job.

The finished link.

The other parts of the reversing mechanism aren't very interesting, mainly hacksaw and file jobs with a bit of silver soldering thrown in. Just for completeness, here's a picture of them all

The Inlet and Outlet Flanges

The flange casting mounted in the 4jaw.

The (elbowed) inlet flange and the outlet flange

The Inlet Flange and Steam Valve

When I put the inlet flange and elbow together, I was still trying to decide whether to incorporate a steam valve. Well, as you can see, the steam valve won!

Finishing

Well, we're almost there now. Since my last update I have spent many hours fitting, polishing and finishing. The last operation before final assembly is of course painting and this is where a lot of models fall down. How many times have you seen a good model ruined by a slapdash approach to painting. I don't claim to be an expert - far from it - but I do like to see my models finished properly. I always use enamel paints, from that very well known and long established supplier! I have tried other paints, notably acrylic, but I didn't like the finish at all - dull and lacklustre - and you can't paint small parts with cellulose car spray! You may think that the colour I have chosen is a bit orange but it isn't. It's just the way the camera / computer renders it. It's actually No. 19 red.

The painted parts waiting for another coat ( I usually use 4 coats )

Putting it all Together

The bottom half of the engine being built.

And Finally....

The finally finished engine.

What the photo doesn't show is the time and effort that goes into setting up the eccentrics to get the timing right. But that all pales into insignificance when you get it to run for the first time!

On Display

The last bit that I haven't covered in the preceding description is the making of a plinth and a transparent display case.

I obtained a nice piece of mahogany - that used to be part of a school laboratory bench - from a friend and finished it off with a few coats of matt varnish. It was then rebated around the edge for the case and drilled for the mounting bolts.

The case was made from 3mm perspex. If you haven't worked with perspex before, well it is very easy. Just score a line with a stanley knife about 5 times and then snap the material on the edge of the bench. It's a bit daunting the first time, but you soon get the hang of it. The various parts are then glued together with Tensol adhesive which is specially formulated for perspex.

You will find that perspex attracts dust due to its propensity to acquire a static charge. I use lens cleaners ( the kind you use to clean your glasses ) as they are anti-static and leave the material perfectly clean.

Anna is now on display alongside Gloria, another of Willy Schneeberger's engines, and my Stothert & Pitt beam engine.