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Beginner's engine build. Simplex 5"g.

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Iain Bachey27/05/2020 11:51:58
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13 forum posts
11 photos

Thanks for the top tips Derek. Much appreciated. I'm a long way off those tasks but I can use this thread to refer to in the future.

New (old) tool arrived today and I love it already. Been wanting a vernier height gauge for a while now. Checked it against a few other non calibrated measuring devices and there's 0.003" between 3 tools. The surface plate is old too so always going to be a few thou tolerance here and there.

APE Microball Vernier Height Gauge

Turns out my hand filing is 0.0025" out. Not too bad considering I don't have a milling machine yet. Obviously I want all parts to be 100% accurate but that's not realistically achievable in my workshop!

Iain.

Jon Cameron27/05/2020 12:14:26
336 forum posts
90 photos
Posted by Iain Bachey on 27/05/2020 11:51:58:

Turns out my hand filing is 0.0025" out. Not too bad considering I don't have a milling machine yet. Obviously I want all parts to be 100% accurate but that's not realistically achievable in my workshop!

Iain.

To be fair hand filing to within 2.1/2 thou isn't bad going at all for a "beginner", It can only get better but a read of this thread may prove useful to put your mind at ease, 100% isn't achievable in any home workshop. Its more a case of the parts fitting together correctly, been able to rotate a axle without it rocking in the axle block for example. For the body work (buffers) 1 or two thou will not make much visual difference, and id not beat yourself too hard for not achieving it to within a thou. just ensure that the buffers are marked up front and back and you use what will be the top surface to align the angle for mounting the frames. this way when setting up the frames there is little chance of the frames been built twisted. Frames assembled on the upper edge of the frames and buffers)

That looks a nice little height gauge. There are ways to asses the surface plate for accuracy yourself. though it rather depends on accuracy you want to achieve, to within a thou maybe two on running/rotating parts is good enough.

Ps keep the pic's coming, tooling is often forgotten in threads like this.

Jon

Edited By Jon Cameron on 27/05/2020 15:14:51

Iain Bachey27/05/2020 21:48:18
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13 forum posts
11 photos

Hi Jon, thanks for the link, I will definitely have a good read.

This is a model engineering beginners project as I've never built a steam loco before but I'm certainly not a beginner at sheet metal work. Just that I usually work with aluminium

I will try not to get too bogged down with 100% accuracy as I will crack up obsessing over extreme tolerance!

The surface plate I own appears to be pretty good, a 0.0015" feeler gauge will not slip under a straight edge on it anywhere. It's a great tool combined with the new height gauge. If I can drill mark accurately then hopefully I can produce a straight loco!!

Iain.

Simon Collier27/05/2020 22:21:18
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352 forum posts
56 photos

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.

David Wasson27/05/2020 22:33:33
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142 forum posts
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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.dscn1861.jpg

Old Crock28/05/2020 10:28:59
29 forum posts
18 photos

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 Crock28/05/2020 11:48:13
29 forum posts
18 photos

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?

ga front elevation .jpg

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.

full size axle box (1).jpg

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.

full size horns.jpg

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!axle box simplex 1.jpg

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 Cameron28/05/2020 13:39:43
336 forum posts
90 photos

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 H128/05/2020 14:09:43
268 forum posts
25 photos

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 Drover28/05/2020 16:26:51
85 forum posts

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 Crock28/05/2020 21:47:18
29 forum posts
18 photos

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:

full size cylinder and valve chest.jpg

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

fuul size valve chest.jpg

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:

fairlie complex valve chest.jpg

Keep calm and carry on!

John

Rod Clemett28/05/2020 22:39:49
12 forum posts
12 photos
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 Collier28/05/2020 22:44:58
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352 forum posts
56 photos

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 Wasson28/05/2020 23:01:54
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142 forum posts
42 photos

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 Bachey28/05/2020 23:37:34
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13 forum posts
11 photos

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 Wasson28/05/2020 23:56:21
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142 forum posts
42 photos

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.

dscn1817.jpg

dscn1816 - reduced 3.jpg

img_20200528_181122.jpg

img_20200528_181341.jpg

img_20200528_181259.jpg

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

Iain Bachey29/05/2020 07:50:32
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13 forum posts
11 photos

Great photos David thumbs up 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 smile d shame I don't have a vice and a bench set up in the garden!

Iain.

Jon Cameron29/05/2020 08:46:31
336 forum posts
90 photos
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 Bachey29/05/2020 09:00:48
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13 forum posts
11 photos

Cheers Jon thumbs up

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 Wasson29/05/2020 10:50:10
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142 forum posts
42 photos

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

David

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