Beginner’s engine build. Simplex 5″g.

[David WassonParticipant @davidwasson11489]

Posted by Simon Collier on 27/05/2020 22:21:18:

Iain, there is a lot of stuff on Simplex over on MECH forum,

https://modeleng.proboards.com/board/19/general-chat

and build logs on the net generally. My Simplex was built by a sheet metal worker and the plate work is lovely. One thing that makes life difficult is that the whole superstructure is one piece. I want to take the turret off to fit a new one with more valves, but I first have to remove the whole cab and tanks assembly.

Yes, having the tanks and the cab in one piece makes things difficult to be sure. I made my tanks separate from the running boards and the cab.

[Old CrockParticipant @oldcrock]

Iain, I guess you have been sucked into a Simplex build, like me, by oft repeated quotes on this and other forums, indeed by Martin Evans himself in the introduction to the build, that Simplex is a beginners locomotive. Let me assure you it is not! It could have been, it should have been, but in the current available editions (note plural) it is most definitely not for beginners. By beginners I mean novice first time builders like me.

Possibly too late now for you but for a beginners loco you could do no better than a Sweet Pea. It has simpler (Hackworth) valve gear, simple coupling and connecting rods, a marine boiler and, most important, easy access to all the mechanical bits once built. It also has a comprehensive build manual written by its designer Jack Buckler and I am not aware of any errors in it. Jack Buckler actually BUILT the first Sweet Pea. How many other designers actually build the first example of theirs?

Why is Simplex not a beginners loco. Simple. There are just too many errors, omissions and contradictions, all designed, perhaps not intentionally, to trip up the beginner. By the way the site for errors referred to by Jon in an earlier post is very useful but take it from me it only scratches the surface. There are plenty more.

A beginner expects to be able to construct a loco from drawings with everything to fit, possibly with minor fettling, and clear instructions. Simplex is not that beast.

It is no surprise that probably the most prolific part built models you see for sale are Simplex, usually close to but not complete chassis. Sometimes it is just castings where someone has given up the uphill task facing them. What does surprise me is the number of completed Simplex that are around and running successfully but I suspect they were built, or breathed upon, by experienced modellers, not first time builders.

What gives me the right to hold these views? Let me put my cards on the table.

I own a Sweet Pea. I did not build it, I bought it as a ready to run loco with certificates. However I have done a nut and bolt rebuild, redone all the plumbing, converted it into a 0-4-2 and other minor changes. I think know my way around a Sweet Pea.

As for building a steam loco I have never done it. I am a beginner, a novice in that field but I am fortunate to have quite a well-equipped workshop. As for Simplex I am building two! Simplex 1 as I call it I am building from scratch. Simplex 2 I acquired with a brand new boiler which is what I was really after. It came with a part complete chassis which was too good not to have a go at – I thought! It came into my life when my chassis was also half done. It opened my eyes to how two people can interpret the “same” design in different ways, but then it depends what you’re working from!

I have the luxury, or should that be the confusion, of having the full size Simplex drawings published by Nexus, the book of words by Martin Evans and copies of the articles from Model Engineer detailing the build.

I also have two friends who are/were building their own Simplex. One got so frustrated at having to remake parts he gave up. The other completed the chassis but the wheels wouldn’t go round, or to be more accurate the valve gear as designed prevented the wheels going round. It spent quite a few hours in the hands of a very experienced engineer (we are talking exhibition display quality) who by removing metal did get it running on air. A lesson to be learnt by beginners – have an experienced engineer to hold your hand – I am lucky to have a number in my club.

Iain, I hope I haven’t dented your enthusiasm (I probably have) but it pays to have a reality check now and then. Realise you are on a very steep road. There will be highs but probably more lows. If you have the patience, stamina and take advice you may just reach the top of the hill. I hope so.

John

[Old CrockParticipant @oldcrock]

Having stuck my head above the parapet let me kick off at the beginning.

This is the full size drawing, General Arrangement front elevation. Notice those two “boxes” on the front of the side tanks?

Let us assume (we are a novice after all) that they are tanks with three pipes leading off on each side down inside the frames. I say assume because they are not shown or mentioned anywhere else on drawings or in text. As there are three on each side we can assume (again) that they are to lubricate the axle boxes.

This is the axle box. Note the lubrication hole is offset.

These are the horns. You have a choice. The cast ones have no hole for getting oil to the box. The fabricated version has a 1/8’’ in the centre of the keep NOT above the oil hole and no explanation as to what it is for.

This is the actual horn and axle box and the oil hole is in the gap. This is the rear driver which will, if it ever gets that far, be hidden under the boiler and behind the side tanks. Good luck getting an oil can in there. Lubrication of the axle boxes is pretty fundamental!

If the axle boxes are lubricated from the tanks referred to what size pipe? Does it rely on gravity? Where do the pipes run so as not to interfere with any other part of the mechanicals. Straight forward for a novice?

[Jon CameronParticipant @joncameron26580]

John,

While I agree with the points you have raised, not to stifle the enthusiasm too much Sweet Pea that you mention also has errors, and as pointed out on the first page of this thread. There is many published drawings, all contain some errors, unfortunately it is human nature to miss something.

Just last night I got a reminder of "engage brain, measure twice, and cut once". I was drilling holes for my motor to mount a different way on the fabricated layshaft. I had accurately measured, the width of the holes, the distance between them and marked these on the mounting plate, centre popped the holes and got them spot on, drilled through to 8mm clearance all the while checking they were in the centres of the scribed lines, then went to fit the motor. The holes were 20mm off, after a head scratch and recheck of measurements I realised my error. I had measured the 20mm from the datum for the first hole, then the 76mm for the second hole (the distance between the mounting holes) from the same datum point instead of adding the two for the second hole.

So you see human nature will unfortunately make mistakes even the prolific LBSC made mistakes on his drawings, or referred to previous text to save repeating. Thus making his designs hard going for a beginner without full access to previous articles. His boiler designs are now outdated and need additional bushes fitting and a different stay arrangement in a lot of cases to be brought up to current thinking and guidance on what classes a safe model engineers boiler.

With regards to the rear axle oiling, perhaps a flip top oiling pot could be located to provide oil to the rear axle box, either side of the frames under the footplate, with a pipe running through to provide drip fed lubrication to the rear axlebox. When in steam the oil will become more fluid, and easily run down a thin bore pipe so long as the end of the pipe is chamfered to overcome surface tension in the oil.

One other note regarding axleboxes and their springs, until the loco is fully assembled mounting the springs can cause the axle to not be in running position, to align and set up the motion. It would be better to bolt the axle boxes in position with a 1/8" packer piece of steel that has been deburred on all edges, between the keep and the lower side of the axlebox. This will set the correct ride height allowing the valve motion to be installed and set without adding variables to the mix.

The best that can be done is to study the links and hopefully avoid pitfalls of those that have gone before. Or worse given up.

Jon

[Phil H1Participant @philh196021]

Iain,

Excellent thread. I prefer to see these threads where somebody is actually having a go at building something. I understand that building any locomotive will not be easy but nothing worth doing is ever easy is it?

Please keep going and please keep posting the pictures.

Phil H

[Derek DroverParticipant @derekdrover32802]

Whilst we're talking about lubricating the axles… I'll again suggest sealed roller bearings, as this removes the issue altogether. This is what I'm doing on my L1 project.

What I've done on my Simplex rear axle (which needed rebuilding after only 4 years running due to ash ingress and excess wear), I now lubricate the rear axle through the ends of the axles, with a large dia hole drilled some way deep into the shaft. The end is sealed off with a stainless ball held closed by a spring. This is stopped in place by a smaller dia coned piece, loctited in. The axle shaft is then cross-drilled through somewhere about the mid position of the axlebox. This allows for oil to be pumped into the axle bearing and keep a good few ml as reserve whilst running.

D.

[Old CrockParticipant @oldcrock]

Jon, where can I find the errors on Sweet Pea? I did not build mine but I would like to know if and where it may differ from the original.

I know your point about self inflicted errors, I am sure we have all made mistakes but by and large they remain private! I am often told by my mentor about LBSC’s tendency to refer to earlier articles in his builds. Not many people have the space to store a full set of ME’s!

Your suggestions for oiling the axle boxes are welcome but the purpose of this thread was to point out the pitfalls for the novice. Most beginners will be well past the stage of completing the axle boxes etc before realising the problems in store for later.

Derek, the same issue applies. Sealed roller bearings are fine but they are not part of the design and are unlikely to feature in the novices thinking. You obviously learnt the hard way! A club member has suggested oiling through the axles as you suggest. Not an easy task when you have got past mounting and pinning them to their axles. Another vote for having an experienced engineer to hold the beginners hand.

My posts are trying to bring some realism to the “the Simplex is a beginners locomotive” mantra and to highlight the errors and omissions in the Simplex so let us move on ….. to the valve chest. Concentrate on the left side where the valve rod enters the boss.

This is the full size drawing of cylinder and valve chest, notice the vertical line in the bore of the boss. To a novice is that important and if so what does it represent:

This is the full size drawing of the valve chest on the same sheet:

That line must have been a draughtsmans smudge ‘cos it has disappeared. Note to novice – ignore it.

Can you see any screw thread? The builder of my Simplex 2 could not either and made a close fitting insert to slide in the valve chest with a blind hole for the valve rod. No fixing shown and of course as soon as air pressure is applied the insert shoots out. Cured by some Loctite high strength retainer. However this design is contradicted by Martin Evans in the text where he says “This end must be tapped and plugged, using 7/32” x 40T tap if available, otherwise open out the last 3/16” to 7/32” and tap ¼” x 40T”. A contradictory case of do as I write not as I draw!

This is what the valve chest drawing should look like, taken from Terrence Holland’s series on a Fairlie Complex based upon Simplex running gear:

Keep calm and carry on!

John

[Rod ClemettParticipant @rodclemett60985]

Posted by Old Crock on 28/05/2020 21:47:18

This is the full size drawing of cylinder and valve chest, notice the vertical line in the bore of the boss. To a novice is that important and if so what does it represent:

At a guess, I'd say it represents the end of the valve rod, which is included in the cylinder arrangement drawing.

Clem

[Simon CollierParticipant @simoncollier74340]

I agree that it is not a beginners engine, especially with Walschearts valve gear that even have slotted radius rods with dies. Personally I couldn't live with a marine type boiler as on Sweat Pea. The Blowfly was designed as the easiest possible beginners loco. There are many here in Oz and few Sweat Peas. It has only slip eccentric valve gear, but many happily live with this. Also it depends on the beginner. My Simplex was the builders first loco and it is a beauty. My first loco is a Springbok and I had no metal working experience at all, whereas our OP does have. Again I suggest the OP finds a detailed build log online. They usually detail faults and problems encountered.

[David WassonParticipant @davidwasson11489]

The "draughtsmans smudge" is clearly the end of the valve rod. The upper drawing shows the rod in place and the rod terminates inside the boss with a little space between the ebd of the rod and the bottom of the blind hole in the boss.

In the lower drawing, the "draughtsmans smudge" dissappears because the drawing does not show the valve rod in place, or the slide valve, or the packing nut.

[Iain BacheyParticipant @iainbachey]

Thanks for all the input chaps. It's obvious that this loco has been interpreted in many ways, not everyone's cup of tea. It is right in saying that, after a fair bit of research and lurking on these forums, I decided to go for the Simplex because it was advertised as a beginners loco, having never built one before i assumed this to be the best option. Also i do like the look of the finished model. I will continue as planned and seak advice where needed, probably lots of advice . BTW I have no build instructions or books, just drawings I bought from GLR Kennions. I'm very excited about this project

I have been in contact with a couple of local clubs, but due to the current state of affairs it's unlikely that I'll get to attend any local club meeting and running days any time soon! I will join a club as soon as possible. The experience and information that seasoned club members will have will be invaluable.

If it cools down this week I'll get the filing done on the 2nd frame and update you all with my progress

Just like to say thanks again for all the comments and info.

Iain

[David WassonParticipant @davidwasson11489]

Having built a Super Simplex, it is not perhaps a "beginners" locomotive, but, it certainly can be treated as a first locomotive for a model engineer with some experience. I would probably never recommend building a locomotive as a way to learn model engineering, the learning curve would be pretty steep this way. An easier way to start would be to build a stationary engine before moving on to a locomotive.

The "simple" thing about Simplex, is that it is devoid of all the detail components that can make a locomotive build seem to go on and on forever. It is designed to get you on the track in the least amount of time with a locomotive that has a real locomotive style boiler and valve gear that operates much like the full size and can be notched up. Six driver wheels for plenty of traction, and no tender to build. A freelance design that can be made as detailed as the builder chooses, or, just as drawn. Yes, there are problems with the original Simplex, and some of the issues were addressed with the Super Simplex.

I got my chassis running on air in 9 months and running on it's own steam on my club track in 23 months.

As for getting oil to the main bearings, yes, there is nothing about this in the drawings, only the oil holes in the axle blocks and in the horn block castings as shown in the Super Simplex drawings. I created mounting blocks for oil cups and made 3/32" pipes to connect the oil cups to the horn blocks to allow the oil to drip in to the cup on the top of each of the axle blocks. I added a small wool punching in the oil cup so all the oil would not run out. The forward, center axle and eccentric strap for the axle pump have an oil cup mounted on a little block tucked under each side of the boiler. The aft axle has oil cups mounted on blocks inside the cab. A long spout oil can and a stick to open the lid of the oil cup makes it actually easy to oil all the main bearings and the axle pump strap.

This oiling system I installed a year after the locomotive was built. Not hard to retro-fit. The first year, I simply oiled up in the steaming bay from below with a long spout oil can.

Edited By David Wasson on 28/05/2020 23:57:00

[Iain BacheyParticipant @iainbachey]

Great photos David I've got lots to think about. These are all future problems but worth understanding early on in the build so I can prepare.

It's going to be another hot day here in Cheshire so I doubt there will be much progress in the workshop. I find it hard to spend time in the garage when the sun is shinning shame I don't have a vice and a bench set up in the garden!

Iain.

[Jon CameronParticipant @joncameron26580]

Posted by Iain Bachey on 28/05/2020 23:37:34:

If it cools down this week I'll get the filing done on the 2nd frame and update you all with my progress

Iain,

This sentence had me slightly concerned. General practice for loco frames is that one frame is marked out with all hole positions, frame profiles then three holes, either in scrap material or in holes that will be there, are drilled out and the frames bolted together for finish profile filing and drilling of holes. generally the three holes are placed left middle and right and two outermost to the top and the middle near the bottom, or visa versa so the frames are less likely to separate.

I'm currently remaking a set of frames for a 3.1/2" Juliet, where the frames were drilled separately, result…….. I have only found one hole in the whole set of frames that is in line on the two frames. This has thrown a lot of other parts out, and has led to accumulated errors everywhere. cylinders not in line con rods having to have the bushes oversize to allow the wheels to turn which makes everything slack to the point of not running. Bolt them together through three holes and then there is little chance of the frame holes not lining up.

Another thing to look for is if the material you use for the frames has a natural bow in it, (most sheet does) arrange to have the bows facing outward when you bolt together, when assembled the stretchers will pull the frame bow straight.

I know your a sheet metal worker and this may be teaching you to suck eggs but it may also be something your not aware of and quite happily drill them separate.

Keep at it, ill see what other errors can be found on the net for you, save you been tripped up down the line.

I do like the oiling pots on David's example above, just like a real engine oil pots everywhere. A long way off but you said you where going to use this thread for reference so here is some flip top oilers that I found on the net recently for my lathe, may be useful in this application also. **LINK**

Jon

Edited By Jon Cameron on 29/05/2020 08:47:11

[Iain BacheyParticipant @iainbachey]

Cheers Jon

I will definitely be fastening the frames together when drilling. I will select a few holes and probably rivet them together, not decided on fasteners to use yet. I do have "skin pins" so i could use those. Easier to disassemble and reassemble when required. I don't have any fancy DRO on a milling machine so it will be hand drilled either using my pillar drill or a windy and a drill block.

Iain.

[David WassonParticipant @davidwasson11489]

Iain, check your Private Messages, I have some additional build information you may be interested in.

David

[Simon CollierParticipant @simoncollier74340]

The build series was in Model Engineer, from memory from 1969-1970. Clubs usually have libraries from which the magazines can be borrowed and photocopied. This is what I did.

[Old CrockParticipant @oldcrock]

Interesting solution to the oiling problem David. Clearly the Super Simplex is a different animal to the original Simplex but still omitted to say how to get oil to the boxes.

Don't get me wrong, the original Simplex can be made to work and is quite a nice looking loco, but there are many hurdles for the beginner to overcome.

The Walschaerts valve gear for example will not work without a lot of easing, something that may worry a beginner.

Iain I see that you are only working from the drawings from GLR. I assume they are the same as mine originally from Nexus. When drilling the frames don't forget the 3/16" reamed hole 4 3/16" ahead of the centre axle and in line with the weighshaft. Your drawings will give you no information what they are for! They are to line up the pivot points in the motion plate link brackets, something which Martin Evans failed to mention until "a large number of builders of Simplex have been after my blood the last few weeks".

In the original build in ME this appeared six months after he described the motion plate and link brackets, where he said to locate the motion plate, pull the crosshead right out, slip the motion plate into position and allow it to assume its natural position relative to the slide bars. Fix in this position. This is repeated in the book. No mention that I can find of those little 3/16" holes. In the later admission he says of the large number of builders "They complain that the slide bars are 1/8" too short! Unfortunately for me, I have been telling these good folk that the mistake is not mine, when all the while there has been an error, though not actually in the length of the slide bars themselves". He goes on to explain that error is in the distance of the rear edge of the motion plate from the centre of the driving axle.

This error was caused because he left the drawing (on cartridge paper with a 6H pencil) in the sun and it shrunk. One of the first things I was told in this hobby was never measure from a drawing!

Anyway we are getting ahead of ourselves. Before you get to the motion plate and valve gear you need to tackle the rear cylinder covers! This is the full size drawing

This is the same item in the book with two 2BA bolt fixing for the slide bar:

And this is the slide bar:

Why is there a .010 relief? No mention of threaded hols for the rear of the slide bar where it fixes to the motion plate.

Enough of my whinging. The Simplex will work but not "out of the box". A beginner will need help, possibly lots of it..

My conclusion is that the drawings and write up were a mixture of original work and copies from other designs and they lost, in video terms, a little in continuity.

Keep going though Iain and do let us know how you get on. Good luck.

John

[Another JohnSParticipant @anotherjohns]

Iain;

My first build was an LBSC Tich; there were issues during the build.

No matter – if you want to do it, do it. I did – people kept saying "start with a stationary engine! Build something larger!! Purchase one and fix it up!!!" but I went down the path I wanted to go.

But you have been warned – know that you have to plan ahead and think about fits and interferences. Talk to others and go through the mentioned on-line build logs. Maybe it's part of the fun?

I'm back on my Ivatt 2-6-0 Martin Evans' design; took a break and built a Kozo Hiraoka Shay (first version) and, on coming back to the Ivatt, it hit me just how good a designer and draughtsman Kozo Hiraoka is.

I think that I'd rather build another Kozo engine than a Martin Evans' one; saying that, there's 2 Simplexes at our club, (one regular, one super) and both run and run and run with minor maintenance. (and, I think one had to have its' rear axle replaced after many, many miles on a ground track)

[Iain BacheyParticipant @iainbachey]

It's the fabrication of parts and machining that interests me and in this instance, the result will hopefully be a complete model steam engine. I have been building and flying model aircraft for 30 years and have always built my own aircraft from plans or kits. Don't get me wrong, it's nice to just go 'buy and fly' but I think that is for the throw away generation. I like to put some effort in to get the reward, like most of you on here no doubt.

I will stick with the Simplex and overcome the problems previous builders have come up against, just like they have. You chaps will all help I'm sure, even if there are a few "I told you so's" along the way

Good news is after a fair bit of research I have decided to purchase a milling machine. Hopefully next week. I've been wanting one for many years now and I've got a big birthday this year so I will treat myself I wont go into details of which machine im getting as that will only stir up everyones opinion and I'll save that for another thread! This will aid the build and speed things up a little, although I've not done much milling since my college days. That's another topic all together though!

Iain.

[David WassonParticipant @davidwasson11489]

Iain,

Congratulations on getting a mill! It will really make short work of things that you might otherwise be using a file. I assume you already have a lathe?

David

[Old CrockParticipant @oldcrock]

Iain, I hope you are making progress with your frames. As I mentioned earlier there will be highs and lows. For me today was a high as I got one of my Simplex running on air – after 8 years (not full time!).

From here on it should be plain sailing but I will believe that when it is finished. I just hope it doesn’t take another 8 years as I don’t think I have that time left in my tank😁.

So whatever happens persevere.

John

[Jon CameronParticipant @joncameron26580]

Hi Iain,

Hope all is going well with the frames, i was looking over the drawings and write up in ME over the weekend, i believe i may have found another to catch you out down the line. Appolagies if it was mentioned previously.

The axle pump eccentric has a 1/4" throw. The eccentric strap OD is 1.3/4" (excluding the bolts). So this is 7/8" radius + 1/4" throw of the eccentric, total is 1.1/8". The stretcher immediately behind the axle has a dimension of 1.3/16" to the centre line of a 3/8" plate. So the plate is 3/16" from centre line to its edge, 1.3/16" minus the 3/16" of the centreline of stretcher to the face of the strecher…..Ahhhhh 1" of free space to fit 1.1/8"……

A relatively easy solution to this would be to drill and file, or mill out a section of the strecher so that the eccentric does not foul the strecher at the rear, while it is in the flat and not mounted up on the frame. Say 2.1/16" high, and 1/2" wide, on the vertical centre line and 2.21/32" from the top edge. You will find this will remove the fouling of the eccentric, though it will mean that your frame strecher is effectively cut in half which is no good. You don't need to go full depth but by the time 3/16-1/4" has been removed the strecher is already weakened.

A better solution would be to move the frame strecher and holes to the rear by 3/8" giving ample clearance, but this will also possibly effect the length of the firebox between the frames. So the drawing and suitable amendments will need to be taken into account on the boiler and discussed with your boiler inspector.

Ill keep looking through and see what else i notice on the drawings other than those previously listed.

Wise words earlier in this thread, if it moves, see what else its close to that it could effect.

Regards

Jon

[David WassonParticipant @davidwasson11489]

The eccentric is mounted on the front axle. There is plenty of room for the eccentric strap.

[Jon CameronParticipant @joncameron26580]

Posted by David Wasson on 08/06/2020 17:04:10:

The eccentric is mounted on the front axle. There is plenty of room for the eccentric strap.

My appolagies, must have been having a bad day yesterday. Don't know how i missed that??

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