Southwold coach
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- Trainee Driver
- Posts: 994
- Joined: Fri Oct 05, 2018 6:30 pm
- Location: South West Wales
Re: Southwold coach
Rick
I couldn't resist the challenge of drawing up a complete compensated cleminson chassis.
The idea being that the springs actually allow the axle boxes to move up and down in the W irons.
It incorporates Philips arrangement and my arrangement to limit sideways movement of the centre axle.
It looks like this:
The end trucks are intended to be pivoted at the holes and the centre truck free to do what it likes. A 3mm diameter stainless rod is intended to go through the holes in the uprights under each truck.
Individual components are W irons, spring/ axle box, and truck:
If anyone wants the STL files or the Sketchup file then provate message me.
Trevor
I couldn't resist the challenge of drawing up a complete compensated cleminson chassis.
The idea being that the springs actually allow the axle boxes to move up and down in the W irons.
It incorporates Philips arrangement and my arrangement to limit sideways movement of the centre axle.
It looks like this:
The end trucks are intended to be pivoted at the holes and the centre truck free to do what it likes. A 3mm diameter stainless rod is intended to go through the holes in the uprights under each truck.
Individual components are W irons, spring/ axle box, and truck:
If anyone wants the STL files or the Sketchup file then provate message me.
Trevor
Re: Southwold coach
I like the idea of the functional leaf springs. Would ABS be more flexible than PLA do you think?
Rik
Rik
Re: Southwold coach
Definitely. Actually I'm not sure even ABS would be flexible enough though.
Philip
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- Trainee Driver
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- Location: South West Wales
Re: Southwold coach
I think it would be sufficiently flexible.
The springs on the wagonette actually work as springs - that is what makes me think it would.
If a particular spring is too stiff it can be altered. Different parabola. Different width different thickness.
Of course it is an experiment. Nothing ventured nothing gained.
Worth trying?
Trevor
The springs on the wagonette actually work as springs - that is what makes me think it would.
If a particular spring is too stiff it can be altered. Different parabola. Different width different thickness.
Of course it is an experiment. Nothing ventured nothing gained.
Worth trying?
Trevor
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- Trainee Driver
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Re: Southwold coach
If you want to play around with it give me some dimensions for the southward model and I can print off appropriate parts, try it out and send you a set which seems to work best
Trevor
Trevor
Re: Southwold coach
I'll press ahead with what I've printed out for now, but if it doesn't workout, I'll be in touch!Trevor Thompson wrote: ↑Thu Nov 26, 2020 9:18 pm If you want to play around with it give me some dimensions for the southward model and I can print off appropriate parts, try it out and send you a set which seems to work best
Trevor
Rik
Re: Southwold coach
I’ve 3D printed springs in PLA for a 00 gauge tension lock servo operated uncoupling device with great success. ABS is springier so probably even more suitable!
If you want some light bedtime reading try this paper I found.
https://iopscience.iop.org/article/10.1 ... 042008/pdf
If you want some light bedtime reading try this paper I found.
https://iopscience.iop.org/article/10.1 ... 042008/pdf
Re: Southwold coach
I have to admit I am amazed by the resourcefulness of you 3D printing fraternity, and of course impressed.
Re: Southwold coach
I'd be very wary of trying to make plastic springs work reliably. Especially the polymers available for home printers.
Flexibility and springiness are very two different physical properties, the relevant measurement is Young's Modulus and polymers have very low results.
The other problem with polymers is that they creep under load. It takes time, but over months the shape of the spring will change. We found acetal was the best injection moulding polymer for making springs, but I've seen that creep over time.
If you want working springs, design the print to use phos bronze strip/wire, or music wire, as the spring element which can be threaded through the axle box print and hidden behind the dummy springs.
I have a vague memory that something like this was available in P4 in the distant past when I still read MRJ. Probably based on a fold-up etching and suitable wire, which was the high tech of the time.
The model looks good so far and given your interest in the Southwold, I hope you can get it to run in Cleminson form.
Regards,
Graeme
Re: Southwold coach
Contrary to popular belief, Youngs Modulus has nothing to do with metal, springs etc. It is in fact the definition of a corset: " Extension is proportional to load within the elastic limit"
Sorry, I'll get me coat!
Philip
Re: Southwold coach
This reminds me of the discussions which occur on my weekly walks with a group of friends from the village (before we were limited to walking with just one other person). One was a Mining Engineer, one was a chemical engineer, one was a mechanical engineer and the other was a secondary school science teacher ( with a First from Imperial).
As a former primary school teacher, I sometimes just let them get on with it ......
Rik
As a former primary school teacher, I sometimes just let them get on with it ......
Rik
Re: Southwold coach
More or less finished the coach.
Not the best photos. The weather has been awful all day here and so not been able to take it out into the garden for a test run and get pictures in decent lighting. I've not yet managed to give it a proper run over the whole line, but it now seems OK over the most undulating section .....
Weather permitting, I can test out its running characteristics at some point over the weekend
Rik
Not the best photos. The weather has been awful all day here and so not been able to take it out into the garden for a test run and get pictures in decent lighting. I've not yet managed to give it a proper run over the whole line, but it now seems OK over the most undulating section .....
Weather permitting, I can test out its running characteristics at some point over the weekend
Rik
- Peter Butler
- Driver
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- Joined: Sun Sep 09, 2012 10:33 pm
- Location: West Wales
Re: Southwold coach
That's looking very nice Rik, I do hope it lives up to expectations.
The best things in life are free.... so why am I doing this?
Re: Southwold coach
Amazingly spacious and open looking. I know nothing about the prototype but that is a very nice model.
Philip
- Soar Valley Light
- Driver
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- Location: North West Leicestershire
Re: Southwold coach
Hi Rik,
That's lovely! I bet it's going to look the bee's knees with your existing passenger stock. The livery really suits it.
The steps and the handrails have worked out very well. I love the profile of the hand rails and the chain across between them really sets it off.
Are your platforms long enough to accommodate the full rake or is a a project in hand for platform extensions?
All the best,
Andrew
That's lovely! I bet it's going to look the bee's knees with your existing passenger stock. The livery really suits it.
The steps and the handrails have worked out very well. I love the profile of the hand rails and the chain across between them really sets it off.
Are your platforms long enough to accommodate the full rake or is a a project in hand for platform extensions?
All the best,
Andrew
"Smith! Why do you only come to work four days a week?
"'cause I can't manage on three gaffer!"
"'cause I can't manage on three gaffer!"
Re: Southwold coach
The original livery only lasted a few years before being repainted in a plain colour scheme (as per the coach in the background). I chickened out of the fancy livery. Rik
Re: Southwold coach
Thanks AndrewSoar Valley Light wrote: ↑Thu Dec 03, 2020 7:11 pm Are your platforms long enough to accommodate the full rake or is a a project in hand for platform extensions?
Fortunately, they are about the same length as my Leek & Manifold(ish) coaches and so I should be able to get away with it .... provided the six-wheel system works out OK
Rik
Re: Southwold coach
As Philip said, a very open and airy design. Lovely work as usual Rik. It is certainly a very long vehicle to be on six wheels!
Grant.
Grant.
Re: Southwold coach
That really is a very fine carriage, congratulations! A whole rake of them will look amazing!
With those big wide windows it's going to demand your very best figures, not like a small-windowed compartment coach where you can get away with cheap charity shop toys!
I see it's on your test track - surely it won't get round curves that tight?!
Andrew
With those big wide windows it's going to demand your very best figures, not like a small-windowed compartment coach where you can get away with cheap charity shop toys!
I see it's on your test track - surely it won't get round curves that tight?!
Andrew
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- Trainee Driver
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Re: Southwold coach
Rick
That looks very nice.
Trevor
That looks very nice.
Trevor
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