What is a Good Second Steam Engine Model to Build?

[Stuart BridgerParticipant @stuartbridger82290]

Check out Elmer's Engines plans. "Bar Stock" engines with varied complexity. I'm.working on the #29 mine engine as a follow up to a 10V. Albeit with a diversion via a Universal Pillar Tool to help with tapping.

[Paul LousickParticipant @paullousick59116]

Aluminium melts at 660+ deg C. You will need a BIG camping stove.

Paul

[Paul LousickParticipant @paullousick59116]

The Grasshopper Haulage engine published in the recent editions of Model Engineer looks like an interesting one to build and is made from stock materials.

Paul.

[JasonBModerator @jasonb]

I had a bit of a doodle of teh Victoria base casting and my thoughts on costings were about right. To buy two base castings will set you back £122 plus postage from Stuarts. They could be made in the sa,e way as the vertical I pictured above for 1/4 of that, aluminium would be £20 and say £10 for some M3 cap heads and a tube of JB Weld, less if you used steel flat.

Make the basic frame parts

Drill and tap the cross pieces and drill & counterbore the sides then screw together with a smear of JB Weld. Then a bit of milling to form the pads for various parts

Finally add some feet, round the edges over and a bit of filler to add fillets to internal corners. I have also shown a bit more shape and taper to the base which is easily done by milling round the outer edges. Also omitted the unused bearing mounting pad.

If it were mine I'd probably go a bit further adding an integral "cast" mounting for the governor. Changing the way the cylinder mounts as the angled brackets onto the cylinder covers would never be seen on full size but just allow the same casting to be used on several engines. Would also do away with the feet as they are not really scale and show it is a model going for some round bosses on the top edge of the base for studs right through.

[Henry ArtistParticipant @henryartist43508]

If you've built a steam engine how about a boiler as your next project?

PM Research do a couple of boiler kits. The materials supplied with these kits are an absolute joy to machine. The only problems I have with them is translating those oddball 'merican measurements into something sane (i.e. metric)!

GLR Kennions also do a very nice boiler kit.

If it must be an engine the kits sold by Bengs Modellbau are very good indeed. Most of the milling is already done for you so the only machines you really need are a lathe and a drill press.

And if you fancy having a go at something "a bit different" take a look at the casting kits available from TS Modelldampfmachinen…

[Paul LousickParticipant @paullousick59116]

As well as bolting together plates as a substitute for castings, they can be silver soldered if made from steel or brass (and cast iron).

Also have a look at the early editions om ME. There are a number of different engines to build and a free set of detail drawings.

Paul.

Edited By Paul Lousick on 12/10/2020 09:53:29

[Dr_GMJNParticipant @dr_gmjn]

Thanks all.

OK, so I'll fabricate the box beds – I suppose when I buy the plans I can scale them if there are no external dimensions. The 10V box bed drawings have no dimensions apart from hole centres – not even an overall height.

What would be the best setup method of machining the draw and raised base on the sides, to reflect the casting?

Do you put JB weld on the face-to-face interfaces, and sand back?

Also, to give some texture to the surfaces, and reduce any milling marks, could they be shot-blasted before machining the pads?

How about the governor? Same deal in terms of buying only the essentials?

I appreciate all the comments on alternative designs, but I don't really have any reason to go with another design now that the cost issue has been mitigated. OK it's a bit of extra effort, but I'll end up with a model I always liked.

To be honest I enjoy machining a lot more than soldering, so making a boiler wouldn't really be my thing.

I have made a start on compiling the ME articles on the 1" Minnie traction engine. My plan is to buy castings and parts as and when I have the spare cash. Hopefully by the time the Victoria is done, i will be in a position to at least make a start on the traction engine.

It seems like a good plan to a) Have the satisfaction of completing another engine, and b) Achieve my ultimate goal of building a live steam traction engine. I must admit I hadn't envisaged doing this at this point on my model engineering career, but it seems do-able, considering a bit of man-maths.

Once again thanks for all the advice.

[JasonBModerator @jasonb]

Plans show the machined features but easy enough to get overall sizes and thicknesses.

For this one I would make up the basic frame and then the ends can have the draft and moulded detail added by holding at an angle in the vice, the sides would need the underside of the vice packing so that work is therefore at an angle. A flycutter could be used as could a corner radius milling cutter or just use a flat ended milling cutter and add an internal fillet with filler. Have a look at the base of this engine being built.

Yes a smear of JB Weld on the mating faces. Use car body filler to add fillets to internal corners and fill the screw holes as it's quicker to sand than JB Weld.

If you think that an engine like this is probably 1/12 to 1/16th scale in most peoples eyes there will not be much of a cast texture at that scale but yes blasting will work as will spraying thick primer at low pressure or using a splatter cap on the airbrush.

Plenty of nicer governor details about that don't need castings, etc, always feel the Stuart ones look rather heavy. The Princess Royal variation that I mentioned has a governor that stands between the two box beds and would be an option, bear in mind that in these scales the governors are usually more cosmetic than working.

Edited By JasonB on 12/10/2020 15:14:04

[Dominic BramleyParticipant @dominicbramley60728]

If when you get the drawings you find they don't have the dimensions you need, then let me know and I will get my calipers out. I have the full kit in an unmachined state.

Regards

Dom

[Dr_GMJNParticipant @dr_gmjn]

Posted by JasonB on 12/10/2020 15:03:07:

Plans show the machined features but easy enough to get overall sizes and thicknesses.

For this one I would make up the basic frame and then the ends can have the draft and moulded detail added by holding at an angle in the vice, the sides would need the underside of the vice packing so that work is therefore at an angle. A flycutter could be used as could a corner radius milling cutter or just use a flat ended milling cutter and add an internal fillet with filler. Have a look at the base of this engine being built.

Yes a smear of JB Weld on the mating faces. Use car body filler to add fillets to internal corners and fill the screw holes as it's quicker to sand than JB Weld.

If you think that an engine like this is probably 1/12 to 1/16th scale in most peoples eyes there will not be much of a cast texture at that scale but yes blasting will work as will spraying thick primer at low pressure or using a splatter cap on the airbrush.

Plenty of nicer governor details about that don't need castings, etc, always feel the Stuart ones look rather heavy. The Princess Royal variation that I mentioned has a governor that stands between the two box beds and would be an option, bear in mind that in these scales the governors are usually more cosmetic than working.

Edited By JasonB on 12/10/2020 15:14:04

OK I'll look into governor details a bit further.

[Dr_GMJNParticipant @dr_gmjn]

Posted by Dominic Bramley on 12/10/2020 16:34:09:

If when you get the drawings you find they don't have the dimensions you need, then let me know and I will get my calipers out. I have the full kit in an unmachined state.

Regards

Dom

Thanks Dom. The 10V drawings are 1:1, so assuming the Victoria is similar, for something like the box beds I could scale them. Presumably the hole centres and thread types are on there, which is the main thing.

[Dr_GMJNParticipant @dr_gmjn]

Guys – any idea what grade of Mild Steel the components are on Stuart models? The crank web material I got from my supplier was a bright (drawn IIRC) Mild Steel. Is this right for the rest of the components such as connecting rods, crosshead guides etc etc?

Also, presumably the cast iron bar for the piston and end caps (the ends withoug the packing) isn't anything special?

Thanks.

[Ramon WilsonParticipant @ramonwilson3]

En1a freecutting steel will be fine for all parts on the Twin Vic. Continuous cast bar available from all the usual sources will be perfect.

 

 

Personally I wouldn't use cast iron for the piston but bronze instead and fit it with a PTFE filled yarn packing about 1/8 – 3/16 square in section. With a piston about 2 thou down on diameter this will give a virtually friction free fit but with an excellent seal and compression. I fitted cast iron pistons to my Twin Vic only to find the moisture left from running had rusted and seized solid over the long period before running again. Stripped it down, done as above, never had that problem since. To give some idea of the compression achieved, if I close the stop valve on the double diagonal engine and wind the flywheel backwards the compression builds up suffiicient to turn itself over about 3-4 revs. With valve open it doesnt feel as if there are any pistons fitted. Done this on all engines ever since but they do only run on air.

This is the sort of packing I mean – piston is out of the Waller engine

 

As fitted

I usually make the groove 2/3 thou shallower than the nominla thickness and the groove 2/3 thou wider, and as you can see the packing is fitted with a scarf joint.

I would stress this is only for running on air though I did run the Twin Vic on steam at shows for several years after fitting this method for several years without any problems

Hope that's of use

Regards – Ramon

Edited By Ramon Wilson on 14/10/2020 18:13:29

[JasonBModerator @jasonb]

Square and flat section is likely to be EN3 (080A15) and round EN1A (230M0)

Iron will be what is often sold as "Meehanite" or Grade 250

It's not too hard to machine an oval gland boss with a boring head or a "rounded diamond" one with the aid of the rotary table if you did not want to spend on the casting. Also a round boss and gland with three studs is quite common and easily done on the lathe.

Yes there is enough info on the drawings to come up with the right shape for the bed casting. I have the one for Princess Royal and the only difference with that is it uses modified cylinder mountings more like you would find on a real engine rather than the get around Stuarts used so the Beam cylinder casting could be used. Any queries with sizes just ask, I'll even draw one up for you if needed..

Edited By JasonB on 14/10/2020 18:21:10

[Dr_GMJNParticipant @dr_gmjn]

Thanks Ramon – I like the look of the bronze pistons and packing. I’ll use that method – I need to order some bronze anyway for some other part of the model. Like the 10V it will only be run on air I think.

Jason, thanks for the drawing offer – I’ll let you know as and when. It might be next year when I start on it, although I will start getting materials together now. I’ll discuss metal grades with my supplier again tomorrow. He said that bright mild steel was usually drawn, and this could leave residual stress in the surface, sometimes causing issues with distortion once the surface is machined away. I know this can be a serious issue on non stress-relieved items in industry, but I don’t know how relevant it is to model engineering in this scale. He also mentioned two types of iron – SG and another; in very simple terms, one cracks with impact, one dents. He said he’d just supply the easiest one to machine based on what I said it was for.

My plan was to buy the Iron castings for the gland ends, and use cast stock For the others. I don’t have a rotary table. I’d like to stick to the original Stuart geometry.

Cheers both.

[Ramon WilsonParticipant @ramonwilson3]

Just a point to watch for Dr G – be sure you get the PTFE impregnated yarn as opposed to PTFE pure yarn. The latter does look superb, is very square and uniform but frays as you look at it. I thought it would be perfect when I first bought some but its a nightmare to fit at these small sizes.

The impregnated yarn is a fibre based product filled, as the name suggests with PTFE and silicone. It's soft and waxy to the touch whereas the other is very firm with little give.

As Jason suggests the cast iron of choice is Meehanite or grade 250.

SG iron is lovely stuff to machine but SG stands for spheroidal graphite and believe me you and your work area will be black everywhere – for some time!!! I've got quite a bit of it stashed away but would always go for the continous cast (Meehanite/Gr250) every time and that's black enough.

Rectangular or square section Cold Rolled Steel (CRS) or 'bright bar' contains stresses no matter what size and will manifest itself in machining unless pre-annealed. It can be got over by a careful approach as described elsewhere so many times but that can be a pain. Bright round bar does not appear to move anywhere near as much so providing there's not too much waste square parts can be milled from round bar with less far less concern of distortion.

'Black bar' has few if any stresses – the skin does have to be removed first but much more reliable from a low movement aspect.

Unlike Jason I use JB Weld throughout but I agree that other filler would be easier to file/sand away. It's a truly great product but again I would strongly recommend using the standard rather than the fast version. It can be a bit runny when first mixed but it can be thickened with a little colloidal silica or left an hour before using as fillets. As the mixture is squeezed out of joints as brought together my thinking is that using it as fillets gives more strength. Not disagreeing with Jason – just my approach. The product is best bought from ebay mainly for the reason of cost. For some reason this product attracts some of the most diverse pricing depending on source – a trawl on ebay will soon prove that!.

I also bought my packing from ebay – 3/16 square is about the smallest but you can sometimes find 1/8

Hope that's of use too

Ramon

 

Edited By Ramon Wilson on 14/10/2020 22:34:28

Edited By Ramon Wilson on 14/10/2020 22:36:24

[Dr_GMJNParticipant @dr_gmjn]

Thanks Ramon. Any chance you could point me to where the machining of CRS discussions are on here?

By the way – presumably the CRS stock supplied in the Stuart kits also needs careful machining? I've not seen anywhere on build threads where people have mentioned it or had any particular issues?

Cheers.

Edited By Dr_GMJN on 15/10/2020 08:49:44

[old AlParticipant @oldal]

If you dont pick out the type of model yourself and do the research on whats available and all of the 'want to build' thinking about things, you will never finish your project.

Building anything needs a lot of dedication, whatever the subject matter. Most if not all model makers have been sidetracked by another project or two or three.

Building the next model means committing hundreds/thousands of hours away to one project. you have to be real sure that is the model for you, not someone else. Ask questions about your chosen design, their are some real rubbish designs hidden away to catch people out and their are some really good designs out there.

Take your time in deciding, dont hurry, and love it before you start.

[JasonBModerator @jasonb]

I don't think there is much on a Victoria that is made from steel that you would need to worry about, the problem mostly rears it's head when you take away a lot of material from one side of your piece of stock and little or none from the other which means the forces within are no longer balanced.

You are likely to see if if reducing say some 5mm x 10mm stock down to 4mm x 10mm and take the 1mm all from one side rather than 0.5mm from opposite sides or if cutting a deep "U" shaped slot you may find the two legs of the "U" closing up.

[Dr_GMJNParticipant @dr_gmjn]

Posted by old Al on 15/10/2020 09:51:10:

If you dont pick out the type of model yourself and do the research on whats available and all of the 'want to build' thinking about things, you will never finish your project.

Building anything needs a lot of dedication, whatever the subject matter. Most if not all model makers have been sidetracked by another project or two or three.

Building the next model means committing hundreds/thousands of hours away to one project. you have to be real sure that is the model for you, not someone else. Ask questions about your chosen design, their are some real rubbish designs hidden away to catch people out and their are some really good designs out there.

Take your time in deciding, dont hurry, and love it before you start.

Thanks Al. The Double Victoria has been on my list ever since I first saw a Stuart catalogue, perhaps as long ago as the 1990's, so it's definitely one I want and will see through to completion. There have been no real issues raised about the model on this thread, and I prefer it to the alternataves proposed, so that's fine. I'll be doing some DIY in terms of the box beds, and sourcing my own materials and fasteners, so that'll add a bit more to my experience.

The traction engine – again I mentioned it as my ultimate ambition. I admit I've not gone into much depth on this in the past, but having researched the 1" Minnie a bit more, it seems ideal for me, and the equipment I have.

I appreciate the comments, and its wise advice to go with something you actually want and like – which I have done, but I've also noted the advice from theis forum too. I think I've got a good way forward. It is going to take years to complete both models, but that's kind of the point. At the end of it the model engineering itch will be well and truly scratched. After that, I'll re-evaluate. Might even get that paper Bismarck finished!

[Ramon WilsonParticipant @ramonwilson3]

Dr G

I'm afraid I can't point you to a specific thread but the situation has been covered many times. I would think that the steel provided by Stuarts would be the same as described.

This is not a big issue but it can be annoying. As Jason says the problem arises when a cut is taken on one side of a piece of CRS flat/square bar. The side you have just machined then exhibits a nice curve when released from the vice. The deeper the cut the more pronounced this can be.

Shallow cuts and reversing the piece in the vise to equalise the stress relief is a method to overcome this characteristic but as previously said can be a real pain particularly if the part is long and thin. Personally I would choose black bar over bright for most parts that have any substance – get rid of the skin and you have your basic stock material – be prepared though – black bar does not have nice square edges as obtained! Or as said, and lately favoured, mill something from round EN1a.

Apart from the two Con-Rods there isn't going to be much on a Twin Vic that will cause you these issues though getting those cross head bars dead flat from CRS might prove trying – it's just something to be aware of.

Regards – Ramon

[Dr_GMJNParticipant @dr_gmjn]

Thanks Ramon.

I've just sent the materials list to my friendly local supplier, so we'll see what comes back in terms of price.

Looking at the number of different sections, I think they may well be specified such that some critical parts, such as slideways, don't require much finishing, therefore the distortion issue is reduced. For example on the 10V, the Bright Mild Steel crank webs only needed drilling & reaming, and their ends radiussing. I was wondering why the cylinder ends, valve chest and cover were all cast, perhaps that's why?

Thanks.

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