Help with 'Speedy' valve gear and other issues...

[Roger]

I see what hagley is getting at, but I don't see CAD in that light at all. It's simply a precision tool that makes as much difference to the workshop as swapping a steel rule for a vernier caliper. It's no substitute for common sense but allows us to spot the things that most builders find out the hard way.
Making things to suit is not a satisfactory way to make anything in my opinion. It's a recipe for chaos and one that Whitworth and others laid showed the way forward with interchangeable parts. It's hard to think of anything in the engineering world where the parts are not made to the drawing in the knowledge that they are correct. That's not a utopian view but the reality of mass production. Tolerances are all part of that and are not to be confused with incorrect or approximate dimensions.
I'm not on any timescale to finish this, it doesn't trouble me to imagine it might never be finished. The journey is much more interesting than the arrival.

[Deleted]

You are a complicated man Mister 4930!------------ Jeez, you ought to see it from this side of my eyeballs !!.......... I've had a similar style of engineering life to yours it would seem...Rectifying others so-called "Proper jobs" etc.....My last posting was as a civilian Engineer working ( sorry, wrong terminology....that should read "Employed"...) within the Army's BASE REPAIR system here at Telford, Shropshire...It's quite natural to find Whit. nut and bolts alongside AF and Metric on a day-to-day basis........

[jma1009]

with SPEEDY it depends how far you want to go! do you just want to rectify the valve gear problems? will you get fed up at looking at an atrociously designed backhead and fittings? will you build a boiler to the drawings only to have your club boiler inspector say 'im not happy with that - you should have added bushes here, and extra stays here, dont like the barrel seam you should have done it this way these days etc'?

very few of us can afford the luxury of a commercially made boiler. i certainly cant, and it is one of the bits of loco building second to valve gears that i enjoy the most.

as roger has already noted there are quite a few basic dimensional errors on the SPEEDY boiler as well as it being 'overscale'

cheers,
julian

[Deleted]

I've just put the finishing touches to the production drawings for my 5" Bear....The one thing that became apparent very early on was the lack(in my case anyway) of a Proof Reader ( I wish I'd had access to CAD in those days !! .. All done by "hand and eyeball")....Perhaps that is what CAD is really doing ie}--- giving the visual, moving proof that the dimensional concept is either "Go" or "No-Go" ??........I suspect that the "Proof Reader" facility may have been missing with some of our earlier designers as well, who knows ?? ------------Trouble is STRIPLAR, the world of Model Engineering is not the world of mass production---more's the pity !!...And we quite often have to make things to suit in order to get it to work at all....( "Make do and mend" in the Royal Navy)...I was trained to hand-craft to + or - 0.005" by ruler, however not everyone can(or wants) to be that accurate...But I am in full agreement with you regarding design errors in Engineering Drawings...Unfortunately these are like a virus that's spread exponentially across the globe( literally, given the interest that there has been down the years)...It's up to us to self-police and rectify where possible.....A "clearing house" approach is called for...Ah, now there's a good name to start with , eh ??--------

[uuu]

I'll just put in a little cheer for Ken Swan, whose drawings are so clear to interpret, and where the errors are few (I wont tempt fate by saying none).

I do admire models of a full-size engine, but that's not for me. "That bracket's in the wrong place! Did you know that in 1932 someone splashed a bit of blue paint on that spot?" If I want to make the saddle tank shorter, I can.

Since film analogies seem to be popular at the moment: "He's not GWR, his name's Speedy Brian, and he's just an ordinary boy."

[donashton]

Well we all have different opinions. A mountain or mole hill depends on which pair of glasses you wear. At least a lively forum will help others. Meantime, all and sundry, including half that can't read a drawing anyway and whose workshop consists of a knife and fork, have been having fun and frustration bashing round the track with their Speedy or whatever since well before the war. What's the problem?

Don.

[suctionhose]

let's all revel in that perfect world for moment...

The wiki thing can work very well. I know companies that use them. You pay a subscription to join. No good to an archivist because the information changes according to contemporary opinion. Re write history as you please!

However, for the purpose of what we are discussing, a wiki is ideal.

I feel there should be a commercial element to it though. "Doing it for free" justifies a lot of excuses, including "It was fun for a while but I don't want to do it anymore".

If a willing person was found to organise such a database and be remunerated for it, it would have a chance of succeeding. And the responsibility could be on sold to another that took the job seriously. Revenue could be from an access fee or subscription to view the wiki on a particular design...

We have the technology...

It hard to pick where the hobby is going next. The technology available often forces the purchase of premade parts over making them oneself. I understand that. I still want to make my own but even I see commercial sense when it's there. Would you cut 60 traction engine wheel spokes by hand when you can laser them for $4 each?

More and more premade parts are becoming available. Whole kits too. People have less time. Space is a premium. Makes good sense. The hobby is changing. Making things the hard way is not what all people want to do now.

Don't like it. Don't want to do it. But that is the reality of ME'ing in the 21st century. One wonders if the original, meticulously researched. one of a kind models are becoming an endangered species?
Ross

[bhk]

As a young model engineering I guess I'm the future of the hobby.

Times are changing in the engineering industry and this comes across to the hobby, I'm a trained cnc programmer and operator as well a traditional machinist and if I had to chose I would go CNC, not because its easier, far from from, but not having to grind a tool every time I want a different radius is just one simple advantage.

I don't think the super detailed and well researched models are a dying art in fact I think it's the opposite, with high quality 3D printing available for pattern making from companies using a mail order system, investment casting available readily, valve gear simulation, water jetting plate work with rivet holes, modern materials, more advanced micro tooling and of course 3D modelling and simulation

I think models are going to get better and better with technology

[uuu]

I look forward to more of the drawings for the engines we build being available as CAD files.

[Deleted]

Hell all--------- As my avatar invokes}---- "Trying to maintain Churchward's standards" and I for one think he would be in complete agreement with bhk and the like....A few months back I,and certain others on here, were tarred with the label "Luddites" because we wouldn't use a "modern process" for a particular assembly method which hadn't been proven to be better than the time-honoured one...( ie Change for changes sake). However, if a system/method CAN be proven to be productive, quicker, more accurate, cheaper, kill problems at source, etc...AND attract newcomers to the hobby then you'll find me at the vanguard of that change.............................................Question}.... What common problem do party-goers and Vampires have the next morning ( Getting rid of the empties !!)

[Roger]

Nov 9, 2013 12:01:41 GMT bhk said:

As a young model engineering I guess I'm the future of the hobby.

Times are changing in the engineering industry and this comes across to the hobby, I'm a trained cnc programmer and operator as well a traditional machinist and if I had to chose I would go CNC, not because its easier, far from from, but not having to grind a tool every time I want a different radius is just one simple advantage.

I don't think the super detailed and well researched models are a dying art in fact I think it's the opposite, with high quality 3D printing available for pattern making from companies using a mail order system, investment casting available readily, valve gear simulation, water jetting plate work with rivet holes, modern materials, more advanced micro tooling and of course 3D modelling and simulation

I think models are going to get better and better with technology

I couldn't agree more. We could also use the younger members to finally make a break from obsolete imperial measurements to designs that are fully metric. 

[Roger]

Nov 9, 2013 13:14:28 GMT uuu said:

I look forward to more of the drawings for the engines we build being available as CAD files.

Absolutely! No more fudged or missing dimensions. Just ask the model what a dimension is from any point, it couldn't be easier. Generate tool paths from the data.... even better.

[Roger]

Nov 9, 2013 15:44:05 GMT nick952 said:

Hi Striplar,

My father (A bricklayer) and I (14 at the time) built a Speedy over 30 years ago, to the drawings as supplied by Reeves (and LBSCs Words and Music), with the valve gear 'modified' by ourselves using calculations based on various books available at the time, including Don Ashtons (Hello Don, you might just remember a father and son from N Wales, joining the Urmston club around the mid 70's).

We left the cylinders in the drawn position, but moved the front brake hanger back just enough to squeeze it in, then made a pair of thinner brake blocks for the front wheels.

Also the piston rod gland was changed to a flanged type, rather than the screwed type drawn, still a tight fit but better.

There are other slight deviations from the drawings, apart from the boiler that was made exactly as drawn.

What machinery do you have available (to bore the cylinders on a Myford 7 series lathe they need to be altered slightly)?

I might add that she went like the clappers from the start.

As an aside, I am returning to model engineering by embarking on a Castle to the Peter (AKA Taff) Rich design.

Let me know if you want more info.

Regards
Nick

Thanks for that Nick. I don't doubt that there are ways round the shortcomings of the original design, but isn't it so much better to be able to find that out before you have a complete locomotive with those issues?
I guess there's plenty of leeway in the valve gear geometry that will allow these flexible beasts to work well enough for most purposes. It's just a shame that the best design, ie Don Ashton's isn't the alternative available from Reeves. Maybe I will get to the point where I can confidently provide those myself. It's already modelled, but that's not the same as actually building it!
I have a large Wasco lathe with  1 micron digital scales and a CNC milling machine with the same. There shouldn't be any difficulty in machining any of the parts with what I have. I was planning to make the cylinders from bar stock and 3D machine them into the form of the castings which are on the expensive side.
I'd love to know what other issues you may have found during your build. Clearances, missing features like the balance tube between the water tanks etc. Anything at all in fact. How about lagging? What did you use and did you increase the diameter of the smokebox to make it look right?
So many questions...

[suctionhose]

The methods of production are changing as technology becomes the norm. It's been stated on this thread, by Striplar himself if I recall, that "the journey is more entertaining than the destination" or words to that affect.

The great strength this hobby has is that within it there are a multitude of sub interests and that it evolves with the changes through time. I believe this point is at the heart of why some old designs "don't measure up" to today's expectations. Time changes all things.

I have wrestled in my own mind about the true standing of a handmade model versus an equivalent model assembled from commercially available parts. Is it a copy or an original?

A couple of models have appeared at the club recently, built in the 1930-40's on a treadle lathe by a gentleman in Sydney. One is 2.5"g Pacific the other is a 5"g 0-4-0. The quality and detail of either is better than most things made today!

In the light of this sort of thing, I conclude the achievement belonging to the person who creates the model with his own hands is much greater than one created from computer generated parts albeit a totally different knowledge base and skill set is required.

While I consider myself a practitioner of traditional skills, much the same as the ones used to produce the original article, I'm still guilty of using someone-else's castings, buying the odd component, laser cutting occasionally etc. Where's the line? I don't know.

I know of 2 identical models being built on opposite sides of the globe, one by hand the other by CNC. End product the same. Journey equally challenging and creative.(the CNC builder made his own CNC machines - that was his primary interest). It's a personal choice which way you go.

Years from now, I think I would like it recognized that producing accurate parts using today's techniques is easier than by hand - so a nice handmade model should be held in high regard and stand-out models of the future could be expected to be both to a higher standard and greater complexity by a corresponding leap!

Ross

[bhk]

Nov 10, 2013 2:27:24 GMT suctionhose said:

Years from now, I think I would like it recognized that producing accurate parts using today's techniques is easier than by hand

Ross

Ross not sure I agree here, programming can get unbelievably complex and some one of jobs would be easier and less time consuming if done manually, I worked in a jobbing shop where we had both machines for that reason.

Where modern techniques really make life easier is repetitive jobs, but. Please don't be fooled into thinking a CNC machine runs itself and spits out accurate parts, it still requires a operator to run in accurately.

[ejparrott]

It took an hour on Friday night to setup and programme a CNC lathe to make the fitted bolts for my chassis. In that time I reckon I could have made 8 or 10 on a manual machine with DRO. For small runs CNC is not quicker than manual, I should know, both are my day job. As it was, I wanted 104, and once the machine was up and running it took 2 hours, with 2 progamme tweaks for the different length bolts, to make 75.

[suctionhose]

Nov 10, 2013 5:37:07 GMT bhk said:

Nov 10, 2013 2:27:24 GMT suctionhose said:

Years from now, I think I would like it recognized that producing accurate parts using today's techniques is easier than by hand

Ross

Ross not sure I agree here, programming can get unbelievably complex and some one of jobs would be easier and less time consuming if done manually, I worked in a jobbing shop where we had both machines for that reason.

Where modern techniques really make life easier is repetitive jobs, but. Please don't be fooled into thinking a CNC machine runs itself and spits out accurate parts, it still requires a operator to run in accurately.

I'm happy to accept what you say is true.

I do wear two hats: in professional life I use any modern method available. The drivers are cost and reliability.
In my model engineering life my desire is to use basic machine and hand tools.

If you're programming and running your own CNC machine YOU are producing the part just as I am on the Bridgeport.

If you are unpacking the latest instalment of your kit model or walking away from a trade stand with a bag of bits made hy someone else then it's not quite the same.

[Roger]

Thank you so much Nick, that's a huge help, I'm sure that will save a lot more wasted time. I've squirreled that away in my notes for reference as I get to each part.
Is there any way you could send me pictures of the buffers on your locomotive, I have no idea what the original looked like.

Roger

[Roger]

I agree with the sentiments that Suctionhose has about the validity of all methods of producing models, whether it be with manual equipment or CNC. I think a lot of the negative attitudes people express about CNC and CAD is because they don't understand them and are intimidated by them. Nobody questions the validity of using a screw cutting lathe to produce a thread, but this is a kind of mechanical computer. It's not cheating because you don't have to skillfully guide carriage to produce the thread any more than it is to use a servo for the same job on a CNC lathe.
I'm at a loss to know why the considerable skill required in conceiving how to progam, hold the work and create parts using CNC machines isn't recognised by many die hards. It's a shame because we should all appreciate each other's skills and value them. There seems to be an assumption that we only use these tools because we don't have the skills to do it any other way. This is nonsense, we just have more options and choose the most appropriate for the job in hand. Sometimes that means we make things by hand too.

[jma1009]

my own equipment is very basic and antiquated. i have often found that only say 10% of loco building is in machining of parts. the remaining 90% to produce a decent working loco is in fitting, fabricating, silver soldering, rivetting etc and doing pipework and valve setting etc. as winsons/modelworks found out and purchasers of same, there is great deal more to building a loco than bolting bits together like a meccano set! it's the attention to all the little details that takes the time and difference in producing a hard working reliable efficient loco, especially when trying to re-create something that is accurate and as close to scale as possible. i can machine a set of wheels up in an evening - but filing off all the flashing and lumps and mould marks on the spokes will take the best part of a week! a similar description could be applied to turning up a set of cylinders when compared to drilling and tapping all the holes etc.

i wish roger every success in his project and his computer graphics of same are some of the most amazing things ive ever seen and quite breath taking. i also heartily commend his proposal to catalogue the original drawing errors. its been done for LBSC's LION/TITFIELD THUNDERBOLT already.

in the meantime i will go back to sketching bits in pen/pencil on the inside of cereal packets!

cheers,
julian