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Steam Engine Number One

A Build Log (hopefully)

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Iain Downs11/05/2019 16:29:37
618 forum posts
524 photos

Thanks for the useful (as always) advice.

I was heading towards buying some 2 inch bar at the show today, but on the way round I saw a part finished engine which used a rod as a cross head guide. This looked like it was half again or twice the size of mine and probably for a steam engine.

What was interesting was that the cross head ran along a rod which inspired me to think of trying that design. The main attraction is a somewhat simplified construction.

Here is the basic idea


The rod would obviously be better secured and could even be secured against the pillars. The rod (or is that bar?) would be steel and I'd use a bit of bronze on the front and back as a bearing material. Obviously that aspect's not in the image, but I wanted to get the idea across.

This seems like it should be easy to do and a bit of shim here and there would allow for adjustment.

Also bought was an inch of 6 inch round for the flywheel, a new machine vice (may end up being too big) and (cheating really) the drain cocks from Polly.

Any comments more than welcome.


JasonB12/05/2019 07:29:13
17849 forum posts
1952 photos
1 articles

Ideally the crosshead would be forked to fit around the sides of teh guide bar and then a plate screwed across the open end of the fork to retain it on the bar. That way you have some sideways guidance and could run the engine in either direction as the cross head will want to pull away from the guide when run one way and against it the other. This sort of thing but a bit simplified


The bottom of teh guide should be retained but that would be easy enough to do by milling flats on a couple of teh cloumns to allow a cross piece to be fitted and the guide fixed to that.

Edited By JasonB on 12/05/2019 07:43:29

Gas_mantle.12/05/2019 08:01:25
359 forum posts
269 photos

Good to see you back at it Iain, I'm still following along with interest.

Jason just as a matter of interest what is that engine in your last photo?

JasonB12/05/2019 08:04:12
17849 forum posts
1952 photos
1 articles

2" scale BB1 ploughing engine (not mine)

Gas_mantle.12/05/2019 08:15:08
359 forum posts
269 photos
Posted by JasonB on 12/05/2019 08:04:12:

2" scale BB1 ploughing engine (not mine)

Looks to be a nice engine

Iain Downs12/05/2019 09:30:25
618 forum posts
524 photos

Thanks, Jason.

I did have in mind to do the fork thing. It just takes me a (relatively) long time to draw things up in OnShape (inexperience more than anything else - the tool is pretty good, probably to sophisticated for me).

I was actually going to bolt some bearing bronze to the cross head on the inside and the outside so that I can could adjust the fit with shims or something - either when the bearing wears or when my fitting turns out to be just a tad rubbish.

I need to think a bit about the bottom support. The plan was to screw the pillars into some blind M8 holes. The threaded holes are already in place and blind to avoid the bolts that hold the crankcase together.

I guess I can find smaller bolts and drill through at 8mm. Or make a mount that clamps to the pillars.



Iain Downs12/05/2019 17:51:24
618 forum posts
524 photos

I'm going to blame my tools. Yes I know what they say.

Yesterday I trimmed my bit of cast for the big end bearing and slit it down the middle (and glued it back together). Today was the day to bore it out.

And I cocked it up. The bore is now 20.35 mm for a crank journal of 20.00. As Mr Micawber might say, 'result, misery'.

Apart from my general cack-handedness, I can trace this particular error to my new (cheap) digital calipers from Aldi. I'd stopped using my old well used (cheap) calipers, because the new ones didn't turn off after 5 milliseconds and if they did turn off, they remembered the position. This makes it just a little easier to use.

Unfortunately, they lack in the accuracy department. I'd bored the hole out to 19.97 mm or so (proud of myself!) and test fitted a bit of the 20mm silver steel - only to find it rattling something rotten. Checked with my old reliable (but turning off) caliper and got 20.35 - which explains the rattle.

Mr Aldi's caliper has been consigned to file 13 and I will now buy another inch of cast and go through the process for the third time of asking. Sigh.

And worse, I no longer have even the most tenuous excuse for not painting the fence.



JasonB12/05/2019 17:55:35
17849 forum posts
1952 photos
1 articles

is the outside to finished size? if not take the halves apart, skim the mating face and stick back together for another go

Iain Downs13/05/2019 16:57:04
618 forum posts
524 photos

Saved by the Ballamy! (sorry).

The width is to finished size. The height is not. My drawings are far a bearing wall thickness of 5mm, but that has come to feel to small, so I then thought about 8mm. As I've not decided I've left top and bottom over 10mm and planned to ask the audience what was sensible later (which turns out to be now).

A few moments with OnShape showed me that I needed to remove about 2.3mm off each face, so I took off 2.5mm.

That went quite well with my new vice and a 17mm face mill,

The thing that made me nervous about Jason's approach was how to centre it in the four jaw. In the best of circumstances this takes me 20 minutes - with an add shaped hole?

It occurred to me that I could recenter the bore the hard way - that is by trimming the sides down until the bore was central and so I too the lazy way out. I pushed the bearing up against chuck face with a centre in the tailstock and adjusted by eye.

Seems to have worked out, though I was clearly a bit over on one side as there is a small groove where the two halves meet.

In other news, I did paint the fence - at least until the paint ran out. Sadly, there is another pot in the shed (taking up perfectly good tool space) so I will have to get back on that soon.

And I got a job offer! So I will have to hurry up and get the hard bits of the engine out of the way before I'm back in full time work...

Off to chill the champers and light the BBQ.

(Pictures in a later post)


Iain Downs14/05/2019 20:44:04
618 forum posts
524 photos

I promised pictures. This one has been a B**CH (Language moderated due to innocent bystanders...).

I started off with good intentions and a nice bit of cast.

bigend bearing raw 1.jpg

The plan conveniently in the photo.

The first thing I did wrong was to trim too much off. I was using the mill to reduce the height by 5mm or so. (1 inch to 20mm). I was taking about 3 mm deep cuts but .5 - 1mm deep if that makes sense. I was (or thought I was) keeping an eye (and a hand) on the Z axis dial mainly as the poor mill was juddering a bit and the dial tended to drift. Despite this it some how cut 4mm deeper at the back than the front.

This one was definitely 'bad workman'! I decided that this wasn't going to work, so reserved if for practice (for the valve face) and bought another bit.

This time I took it down near size on the lathe which worked better. Sliced it in two with a slitting saw as below.

bigend bearing splitting.jpg

That went quite well, though I ended up changing the clamping mechanism as the clamps stuck out to much into the barrel of the saw.

Happy, happy!

Then on to drilling out and boring.

bigend bearing boring.jpg

That seemed to go OK, but I managed to cut it 0.4mm over (see early post passing responsibility off onto my tools!).

All seemed lost until the kind Mr. Ballamy suggested I split, thin and retry.

bigend bearing thinned.jpg

The thing I was worried about was centering, but in the end I just used the centre from the tailpost as here.

bigend bearing recentering.jpg

And added the sticky up bit (sorry, I don't know the correct engineering term - but this...)

bigend bearing rescued side 1.jpg

Then my troubles really began!

I found it (nearly) impossible to mount the block in the 4 jaw and get it centred. In confession, I am TERRIBLE at centring in the 4 jaw. I seem to get the rough adjustment with the chalk circle OK, but then it all goes to pot with the clock and I have to go back to the chalk circle again.

bigend bearing side 2.jpg

In this case matters were made worse as the block was getting gouges in where I tightened up too much. This made adjustments in the other access difficult, with the jaws dug in. I tried some hard shims, but I was getting nowhere (about 2 hours of nowhere by now!). Then I noticed that when I tightened the jaws (I mean reasonably firm not tight tight), the block was moving- moving away from the chuck face.

So each time I moved it to correct a clocking error it was adding another error due to the movement. I have no idea why this is except perhaps it was a fairly low hold with an 'amateurs' vice.

I gave up.

I then had the marvellous idea of trying to hold the 2mm stub in the 3 jaw (the bit I don't know the name for). I thought this probably wouldn't work and I was right. the minute the tool touched the surface, 'Spung!', it jumped off the chuck.

I thought of mounting it on the faceplate or making a stub mandrill, but all of those required quite a bit of work (I have no suitable clamps for the faceplate, though a mandrill could have been possible.

On the verge of packing in for the day and going to take consolation with my friend Vin (Vin Rouge that is), I thought of turning the 4 jaw chucks jaws round to give me a higher grip.

This worked better than I deserved as it turns out the centre hole in the chuck is almost exactly the diameter of my sticky out bit!

bigend bearing side 2 finally.jpg

The jaw height closely matched the bearing height so I needed add some separators to give me space to get in and cut. Even then I struggled to get the tool in and couldn't cut to the edges.

I tool cuts to get to the right depth with the (carbide) tool at an angle and then straightened it out to make the outside of the sticky out but vertical.

Finally, I took it to the mill and smoothed off the corners that were sticking up.

bigend bearing finally trimmed.jpg

Final step with this damned thing is to trim it..


Blue Heeler15/05/2019 06:22:56
189 forum posts

Thoroughly enjoyed this thread, looking forward to your next installment.

Iain Downs16/05/2019 17:05:56
618 forum posts
524 photos

I suck at soldering.

I wanted to do some practicing before I messed up some precision (!!!) crafted pieces of the con rod assembly.

So I turned a rod to match the con rod and made a piece the same size as the big end bearing connector.

lower con rod.jpg

But I cannot make the soldering work.

I have some insulating breeze blocks (I forget the type, but the ones recommend in this forum) for my hearth. Having been told that my B&Q torch wouldn't touch anything much bigger than a ring, I bought a Sievert torch kit (with a 2941 burner - 7.7kW apparently).

This is the part after an unsuccessful attempt to solder

conrod soldering practice.jpg

I'm using 455 solder which has a relatively low melting point and I think that despite the investment in the torch I can't get it hot enough quickly enough. Even spending 5 - 10 minutes heating it up, it's still not hot enough to melt the solder when the solder is touched to the red hot metal.

I first tried it with the parts in a 'normal' orientation (rectangular bit down on the bricks) and then as you see here.

I don't know if I'm not adjusting the torch correctly. The flame isn't quite the neat cone I would expect - though it seems a bit erratic - perhaps something needs tightening or cleaning (but not today).

I suppose I want to check that I should be able to solder a piece of this size with the equipment I've got. If not then I need to rethink the design (super glue and pins?).

In useful work, I started on the big end bearing connector. Now trimmed to height and width.


JasonB16/05/2019 17:17:23
17849 forum posts
1952 photos
1 articles

Should not be a problem with that torch/burner combination.

What flux did you use?

What regulator have you got on the bottle and what have you set it at?

Edited By JasonB on 16/05/2019 17:21:56

Iain Downs16/05/2019 20:48:42
618 forum posts
524 photos

I used the flux that CuP provided with the solder and torch.

This is the regulator.

gas regulator.jpg

It's set to 5 - at least the number pointing to me is 5.

Many thanks


JasonB17/05/2019 06:59:41
17849 forum posts
1952 photos
1 articles

Did you get one of their starter packs? if so it was more than likely their "EF" pack", you would have done better with the HT pack or some HT-1 flux as this will be better for any jobs that take longer to heat.

Looks like a high pressure regulator so should have been giving a reasonable amount of heat at the mid setting, try it on the max to see if your torch burns more, it may not as the jet in the torch will be the limiting factor.

Michael Gilligan17/05/2019 07:40:39
15478 forum posts
668 photos
Posted by Iain Downs on 16/05/2019 20:48:42:

It's set to 5 - at least the number pointing to me is 5.


This appears to be the same regulator: **LINK**

But I can't see the pointer on yours dont know


Edited By Michael Gilligan on 17/05/2019 07:41:31

JasonB17/05/2019 07:45:38
17849 forum posts
1952 photos
1 articles

Well found Michael, if Iain's one is anything like the link then the pointer is at the bottom of the label so pointing to 0 or 1 which would be a bit low!

Iain Downs18/05/2019 15:57:20
618 forum posts
524 photos

Who would have thought it?

You have to turn the gas ON to get a soldering torch to work! Well, well - you learn something new everyday.

I do feel like a bit of a plonker to be honest, But I am truly grateful for my muses who have helped out and managed it without pointing out that I'm an idiot (I wouldn't have managed!).

Today, I practised soldering. I would like to say that this went swimmingly well, but it did not. Yes I am getting more heat and my first go I got solder to seep through one side of the hole (but not the other). The second go got really hot and the solder melted but didn't seep. I suspect in both cases that the parts already having been used for a test meant that there was too much scale or something.

I will make new parts tomorrow and have another go.

I also trimmed down the big end bearing so that the height is right and completed the sizing of the bearing connector. Tomorrow (as well as soldering practice) I will drill and ream the bearing and holder. Shortly after that I will need to develop soldering skills .


Michael Gilligan18/05/2019 19:46:36
15478 forum posts
668 photos

Well done, Iain ... keep at it yes


Iain Downs20/05/2019 09:04:53
618 forum posts
524 photos

My soldering still sucks.

Here is a charming little travelogue of my adventures with a simple soldering task.

The Solder

00 soldering solder.jpg

The Parts. The rod is 12mm, the bar is 10x20.

01 soldering cleaned.jpg

You will notice the dimples. One of the debates in the forum is if you need to use a centre punch to make little dimples to make sure there was space for capillary action. I have no idea if this is a good idea or not, but it kind of made sense.

The the fluxing. I'm not terribly happy with the fluxing. 'Consistency of cream'. Cream this lumpy would go down the sink. Not sure How I can get it smoother or stickier.

02 soldering fluxed.jpg

This is my hearth

03 soldering hearth.jpg

and I warmed it first

04 soldering warming.jpg

Then blasted away. I was expecting a more defined cone on the flame to be honest, though I'm not quite sure why.

05 soldering hot.jpg

The above is about where I gave up. The solder did not appear to melt when touched to the metal (but see later picture) and formed little blobs when I applied the torch. Between the first image with the torch and this was a little over 5 minutes. I do have a series of photos showing the thing heating up, but I don't really see the point of adding those.

I started trying to apply the solder when it started actually glowing and every so often thereafter.

This mess is the result.

06 soldering ugh.jpg

Finally I turned this upside down, but it in the vice applied a drift and a few moderate strikes with a small hammer slit it out as here.

07 soldering split.jpg

It looks like some solder has crept in, but the joint strength is minimal and the solder has not run down the spigot at all.

This is the smallest of all the joints. the crosshead will have quite a bit more metal than this little bar so if I can't get this to temperature then that will be impossible.

Or am I getting it too hot? Or wrong flux. ARGGHHHH!

The joys of ignorance. Not.

As usual any help would be very much appreciated. I have the other end of the rod and another bit of bar just waiting for my next practice.



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