Tim Watson
Western Thunderer
Wow! Information overload for a steam engine.
Thanks
Tim
Thanks
Tim
Scattergun 3.5” King Arthur ‘Sir Sagramore’
- Thread starter Tim Watson
- Start date
Sir Percivale is introduced to the grand daughters.
Tim Watson
Western Thunderer
Meanwhile, various plugs and fittings are being made to allow the boiler to be shell tested at 2x pressure.
Tim
Tim Watson
Western Thunderer
I think Grandpa would need to loose weight to ride on that one Allen! (behind, for sure).
There’s an awful lot to do, so first steaming will be a way off.
Tim
There’s an awful lot to do, so first steaming will be a way off.
Tim
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Tim Watson
Western Thunderer
Christmas came early for me, with a successful boiler shell test for Sir Sagramore.
It wasn’t quite straightforward as there was one internal stay that was weeping under 2x pressure and, needless to say, access was a bit tricky being slightly behind the convexity of the firebox. The original silver solder had inadequately penetrated on the far side of the stay. A couple of hours trying to swage it using a specially made tool, simply rounded off the top. The area was cleaned up using a brand-new, but 50 year-old dental handpiece powered by my equally ancient dental engine, complete with a nasty large inverted cone bur. A front-surfaced mirror, headlight and loupes aided vision.
The whole boiler was then gently heated up on a hearth of firebricks and the gas flame concentrated on the outside of the offending stay. Once up to temperature the solder flashed nicely into the joint with plenty of flux, following the heat.
I have learnt a lot from this little exercise, with very useful advice from my friends in the North London Society of Model Engineers.
Tim
It wasn’t quite straightforward as there was one internal stay that was weeping under 2x pressure and, needless to say, access was a bit tricky being slightly behind the convexity of the firebox. The original silver solder had inadequately penetrated on the far side of the stay. A couple of hours trying to swage it using a specially made tool, simply rounded off the top. The area was cleaned up using a brand-new, but 50 year-old dental handpiece powered by my equally ancient dental engine, complete with a nasty large inverted cone bur. A front-surfaced mirror, headlight and loupes aided vision.
The whole boiler was then gently heated up on a hearth of firebricks and the gas flame concentrated on the outside of the offending stay. Once up to temperature the solder flashed nicely into the joint with plenty of flux, following the heat.
I have learnt a lot from this little exercise, with very useful advice from my friends in the North London Society of Model Engineers.
Tim
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Steve Cook
Flying Squad
There some quality engineering in this loco Tim, its an absolute beaut!
Pleased to see you were able to fix the boiler...tries not to say full steam ahead...
Good luck with carrying on the build, its going to be so worth it to see it in steam.
Steve
Pleased to see you were able to fix the boiler...tries not to say full steam ahead...
Good luck with carrying on the build, its going to be so worth it to see it in steam.
Steve
Tom Insole
Western Thunderer
Great to see you slinking your teeth into the project.
At least it wasn’t a multiple stay extraction job!
I’d love to say I’d love to be doing something like it but don’t have the kind of skills you possess
Keep up the good work I look forward to seeing what 2022 brings for this beautiful piece of engineering
At least it wasn’t a multiple stay extraction job!
I’d love to say I’d love to be doing something like it but don’t have the kind of skills you possess
Keep up the good work I look forward to seeing what 2022 brings for this beautiful piece of engineering
michael mott
Western Thunderer
A tricky bit of remedial work for sure, having just the right tool does help. Even so having to heat up the whole area for just a tiny weep is daunting.
Michael
Michael
Tim Watson
Western Thunderer
The opening to work through was the foundation ring, David, so not that tricky. The set up can be seen below, with the fire brick giving the scale.
The offending stay is not visible, it’s just over the ‘horizon’, but playing the torch onto the outer end of it worked well because the hearth arrangements concentrated the heat. Heating in the firebox was not going to work because of air starvation of the torch, let alone very difficult access. Also solder always goes to where the heat is, so that guaranteed that the joint would be properly caulked rather than just sitting on top: a bit like tinning a rather large soldering iron, really. The whole lot was heated up over 30 minutes to avoid stressing any other joints by thermal shock. Made for a nice toasty workshop!
Tim
The offending stay is not visible, it’s just over the ‘horizon’, but playing the torch onto the outer end of it worked well because the hearth arrangements concentrated the heat. Heating in the firebox was not going to work because of air starvation of the torch, let alone very difficult access. Also solder always goes to where the heat is, so that guaranteed that the joint would be properly caulked rather than just sitting on top: a bit like tinning a rather large soldering iron, really. The whole lot was heated up over 30 minutes to avoid stressing any other joints by thermal shock. Made for a nice toasty workshop!
Tim
Tim Watson
Western Thunderer
I have started to work on the rear end of Sir Sagramore (so to speak) and dismantled the RHS injector. This is more complete than the LHS, including the steam cone.
As for the LHS, there is a delivery cone, seen here with a view from the top.
There is clearly the middle combining cone missing, whilst the relative positions of the other cones can be seen in this ventral view.
The steam cone finishes ahead of the water inlet opening (there is a fine spacing washer next to the mating surface with the injector body)whilst the bell opening of the delivery cone can be seen ahead of the overflow.
It would be good to get one of the Ian Jaycroft injectors working. It will need the combining cone reverse engineering and a ball and plug for the valve on top.
The questions that then arise are:
Any idea how to calculate what overall length / taper proportions the combining cone should have?
How would the combining cone be stabilised in the middle of the injector body?
What size ball for the valve - the hole is 3/32” diameter.
How much lift?
Maybe I’m expecting a bit much of this: I will definitely use a small Chiverton (commercial) injector on the other side, when I can source one.
Tim
As for the LHS, there is a delivery cone, seen here with a view from the top.
There is clearly the middle combining cone missing, whilst the relative positions of the other cones can be seen in this ventral view.
The steam cone finishes ahead of the water inlet opening (there is a fine spacing washer next to the mating surface with the injector body)whilst the bell opening of the delivery cone can be seen ahead of the overflow.
It would be good to get one of the Ian Jaycroft injectors working. It will need the combining cone reverse engineering and a ball and plug for the valve on top.
The questions that then arise are:
Any idea how to calculate what overall length / taper proportions the combining cone should have?
How would the combining cone be stabilised in the middle of the injector body?
What size ball for the valve - the hole is 3/32” diameter.
How much lift?
Maybe I’m expecting a bit much of this: I will definitely use a small Chiverton (commercial) injector on the other side, when I can source one.
Tim
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simond
Western Thunderer
Tim
I have several books which you’re welcome to borrow:
LBSC; Live Steam,
LBSC; Shop, Shed & Road,
Tim Coles; Beginners Guide to Model Steam Locos and
Martin Evans; The Model Steam Locomotive.
All have some info about injectors, including how to make them, and some theory, which will help the set-up.
Drop me a PM and we can work out what to do.
atb
Simon
I have several books which you’re welcome to borrow:
LBSC; Live Steam,
LBSC; Shop, Shed & Road,
Tim Coles; Beginners Guide to Model Steam Locos and
Martin Evans; The Model Steam Locomotive.
All have some info about injectors, including how to make them, and some theory, which will help the set-up.
Drop me a PM and we can work out what to do.
atb
Simon
Tim,
I recommend "Miniature injectors inside and out" by D. A. G. Brown. Available from Camden miniature steam services . camden.co.uk.
D.A.G. is a well known figure in the model engineering world and a most knowledgeable and approachable figure.
After 25 years of O gauge modelling I have moved through the larger gauges before settling on 7 1/4" gauge and have a 9F well under way. Certainly beyond the remit of Western Thunder I think! However this is the only forum I really enjoy.
Greetings to all.
Simon R
I recommend "Miniature injectors inside and out" by D. A. G. Brown. Available from Camden miniature steam services . camden.co.uk.
D.A.G. is a well known figure in the model engineering world and a most knowledgeable and approachable figure.
After 25 years of O gauge modelling I have moved through the larger gauges before settling on 7 1/4" gauge and have a 9F well under way. Certainly beyond the remit of Western Thunder I think! However this is the only forum I really enjoy.
Greetings to all.
Simon R
Tim Watson
Western Thunderer
Thank you Adrian & Simon. I will be getting the DAG Brown book shortly. I think that I might make a dummy Perspex block to assess distances between the cones.
Tim
Tim
Tim Watson
Western Thunderer
Engineering artistry, the reversing mechanism made by Ian Jaycroft.
https://youtube.com/shorts/fDurgpcnIiU?feature=share
Tim
https://youtube.com/shorts/fDurgpcnIiU?feature=share
Tim
Brian McKenzie
Western Thunderer
Very nicely done, Tim. A multi-start left hand thread.
Two starts or more?This image is from an animation of a current O gauge Sharp Stewart loco project.
I worry that I might be silly enough to attempt making a 3-start thread as an engineering challenge, at the expense of much else.
-Brian
Ian@StEnochs
Western Thunderer
A long time ago when I was building a large scale traction engine I screwcut a double start square thread on both brake screw and nut! Once you get your head round the technique it's not that difficult if you have the correct equipment. However having done it once I am in no hurry to repeat the exercise but it's nice to be able to say I could.
Ian.
Tim Watson
Western Thunderer
Bit difficult too see how many starts to the worm as I can’t see the end, but certainly double start.
Currently settling in the boiler: but these Kelloggs cornflakes boilers will probably not catch on.
I have also been working out the plumbing and fittings at the back head: just loosely in place at present.
Trying to work out what goes where is quite tricky, but it’s all beginning to make sense.
Tim
Currently settling in the boiler: but these Kelloggs cornflakes boilers will probably not catch on.
I have also been working out the plumbing and fittings at the back head: just loosely in place at present.
Trying to work out what goes where is quite tricky, but it’s all beginning to make sense.
Tim