Proofed the boiler with air-pressure…

Hmmm. To what test-pressure? Did he also build the boiler? Does the boiler have any previous test documents?

I’d be very wary of that one. Pressure-vessels are proof-tested hydraulically, not by compressed-air, so someone admitting that would make me wonder what other mistakes he’d made.

Especially if the engine is “not in great condition” generally – which could mean major repairs like a cylinder re-bore.

At least the seller seems honest even if not very knowledgeable.

I don’t think there are any manufacturers of ready-to-run traction-engine models in the smaller scales, but you could see what second-hand engine dealers like Station Road Steam and similar specialists have available.

Regarding moving the engine about, even a 1″-scale traction-engine can still be a hefty lump of machinery.

With respect I think this is something all new to you so I would take a lot of advice before buying any engine, and if not already a member join a model-engineering society for help and future boiler-tests. (You only need the latter for running the engine in public including club-only events, but still adviseable if your “public” is limited to your family in the back garden.)

Karl,

First off I would ask what your experience and capabilities / available equipment are?  For example if you buy a used engine that turns out to require remedial work to get to a running condition do you have any machinery or ability to make replacement parts?  It is quite common for individual builders even when working to published / established designs to deviate from the ‘drawings’ if only using alternative screw threads or different materials to those recommended.  Unless it is a commercially produced model the chances of being able to purchase any spare parts are extremely slim.

Secondly I have never heard of a Llewelyn steam tractor?  That is not to say this is not a commercial manufacturer I have never heard of but a quick internet search did not bring up any results on a manufacturer, full size prototype or model design.

If you do not have a lathe / milling machine, basic hand tools etc and some knowledge of how to go about repairing or refurbishing a used model I would strongly recommend you confine your search to a commercial manufacturer that will be able to support you with spare parts if any are required.  I have seen too many people purchase what to them seems to be a “bargain” which has subsequently turned out to be sub standard with serious underlying defects that have been hard if not impossible (poorly constructed or leaking boilers) to rectify.  This has lead to disappointment, unexpected cost and ultimately serious disillusionment for the hobby.  I would always caution against purchasing any model steam engine sight unseen.  In fact it is always best to take someone with experience with you to view and to see the model demonstrated in steam.  This applies even to small models!

Not trying to discourage you at all, just sounding a warning on what you could potentially be getting into with something that is uncommon and potentially unsupported.  Apologies if you have all the required machinery and skills!  If you do not, as mentioned in a previous post Maxitrak (no interest or connection) may well be your best bet as they will be able to supply parts if required.

Best regards,

Paul.

It is not unlike a Minnie with a few variations, compare that to my Minnie

Karl,

A Minnie weighs in at about 13kg and nearly 1/2M long and said to be difficult to fire on coal.

Karl,

For the cylinder to boiler gasket I would use something like Klinger C4324 available as 1mm to 3mm sheet in combination with Rocol Steamseal on the gasket and on the threads of the retaining bolts (I an assuming something that small uses bolts).  Better solution will be shouldered studs which can the tight end into the boiler with a stud box and potentially a better seal between the boiler and the shoulder but that may be overkill in something so small.  There used to be two grades of steamseal the older conventional grade that stayed relatively soft and was great there was also a second grade “manganese” that set rock solid and made any subsequent dismantling rather difficult!  I think the latest modern version is something of an amalgamation of the two.  Fortunately my old tin is still half full and will save me having to try the new fangled stuff!

For the piston “ring” yes one of the traditional methods was graphite packing.  Not the best but Ok?  if what you picture there is still soft then sticking with that may be as good as fitting new.  Try working some steam oil into it with some graphite flake, difficult to say from a picture but what is there doesn’t look too bad.

Paul.

I give up with this forum and an iPad!  The bloody auto correct changes things to what it thinks is better but makes no sense and combined with the form seems the throw ?marks in entirely random places!!!!!

Paul.

You won’t be able to use studs because they point in different directions preventing the cylinder being lowered onto them (if you see what I mean).

EKP do BA Allen screws:

https://www.ekpsupplies.com/ba-socket-cap-screws.html

Take care tightening them – threads in copper may not be that strong.

Paul – thanks for the tip about Steamseal, I’ve got to replace the plumbers’ merchant stuff I used on the Minnie so I’ll give it a try.

By the way Karl, thanks for your comment on the video; in a further test, the stainless steel balls worked fine in the feed pump – it only refused to work once, with the engine being steamed hard, but a quick squirt of cold water on the pump body got it going again.

On 21 April 2026 at 19:26 Andy Stopford Said:

You won’t be able to use studs because they point in different directions preventing the cylinder being lowered onto them (if you see what I mean).

 

Andy,

Ohh yes you can, my 6” which has the same issue (studs pointing in all directions like a hedgehog) proves it.  You just have to think about it a different way!

Twigged it yet?

Ok, you put one stud in on the top centreline of the boiler front and back.  Lower the block and gasket on, then use a stud box to insert the others with the cylinder in position.  Why bother I hear you ask, is that not the same as a bolt?  Well no it isn’t!  With a shouldered stud (plain bit in the middle) you can screw the stud into the boiler right up to the shoulder.  Then give the stud box a whack with a hammer and nip up a bit more, this (should) ensure the shoulder contacts the boiler barrel hopefully improving the seal combined with steam seal on the thread (mine didn’t leak anyway!).  The nut is then free to properly clamp down the flange.  If you use a shouldered bolt it would be very difficult to make sure the shoulder seats when the bolt is at the correct tension.  As I think I said probably overkill for something of that scale anyway but unless using carrot bolts it’s probably the correct way.

Steamseal (well the original) is wonderful stuff, not used the new version.  Another option if you can get it is stag A. That is like a grown up’s red hermetite used extensively on steam flanges in the old naval dockyard that stays relatively soft too but don’t get it on your fingers.  Cylinder cover joints and the like shouldn’t need any sealant at all just a thin joint smeared with grease or steam oil.

Paul.

On 22 April 2026 at 01:11 Paul Kemp Said:

On 21 April 2026 at 19:26 Andy Stopford Said:

You won’t be able to use studs because they point in different directions preventing the cylinder being lowered onto them (if you see what I mean).

 

Andy,

Ohh yes you can, my 6” which has the same issue (studs pointing in all directions like a hedgehog) proves it.  You just have to think about it a different way!…

…Paul.

Fair enough! I don’t really fancy trying it in 1″ scale though – it’s fiddly enough getting some of the bolts in as it is. I do slightly regret not having turned a fake stud end on the heads though.