Author Topic: Little and large - building 2 vertical steam engines.  (Read 29118 times)

Online Jo

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Re: Little and large - building 2 vertical steam engines.
« Reply #90 on: May 20, 2018, 08:04:10 PM »
Looks good  :)


and the 4 is rather smaller than the 5A or the Swan :embarassed:

Jo

When you decide to raid your fondling casting cupboard and sell me a set of castings I might have a go at making one  :-*

I don't have any more 5A's the only other large Stuart Steam engine I have is the No 1  :embarassed:

Yes Stuart do like to cast in only the inlet ports and leave us to machine the exhaust port.

Jo
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Offline Gas_mantle

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Re: Little and large - building 2 vertical steam engines.
« Reply #91 on: May 20, 2018, 09:11:22 PM »
Thanks Jo, are you implying you may have a no1 casting kit for sale  :)

I'm enjoying the challenge making these 2, I'm unfamiliar with castings so it's a bit of a learning curve. The only slight snag at the moment with the no4 is I think the dimensions may have changed over the years. I have a home made trunk guide, a cylinder casting from a different source and a set of plans that are different still, add to that I'm trying to make it in metric from imperial plans and there is plenty of scope for error.

The plans show the total cylinder length at 2" but mine even after machining is 21/4, if you look at the earlier photo, taking another 1/8 off each end would get very close to the ports so something isn't right.

It isn't a problem but somewhere along the line I think the dimensions have been changed so not all castings are compatible with all plans  :headscratch:

Online Jo

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Re: Little and large - building 2 vertical steam engines.
« Reply #92 on: May 20, 2018, 09:39:57 PM »
Thanks Jo, are you implying you may have a no1 casting kit for sale  :)

 :lolb:   :hellno:

My drawings show the cylinder at 2 1/8" long

Jo
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Offline Gas_mantle

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Re: Little and large - building 2 vertical steam engines.
« Reply #93 on: May 20, 2018, 09:54:01 PM »
I have 2 sets of plans one is like yours but the one I'm working off is different so something has changed along the way.

My guess is the one I'm using is in old money and yours is in the new money.


Offline john mills

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Re: Little and large - building 2 vertical steam engines.
« Reply #94 on: May 20, 2018, 11:36:43 PM »
my no 4 cyl casting finished is 2"long  my no9 is 2 1/8  but your working with castings .so you will have to work to the casting  adjust the sizes to suit the casting you have.

Offline Jasonb

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Re: Little and large - building 2 vertical steam engines.
« Reply #95 on: May 21, 2018, 07:05:55 AM »
 The newer 2007 drawing uses a 5/8" thick piston and the older 1953 drawing 1/2" so that is why 2" fits the old engine but a 1/8" longer cylinder is needed for the new one. No doubt the longer piston is needed as Stuarts have moved over to O rings rather than the thinner CI rings

I would not touch the ends now as setting it back up to get the standard end true to the bore will be hard, make your piston 18mm long and the cylinder cover spigots 2mm which will compensate for the extra length created by your 2.25" cylinder
« Last Edit: May 21, 2018, 07:10:11 AM by Jasonb »

Offline Jasonb

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Re: Little and large - building 2 vertical steam engines.
« Reply #96 on: May 21, 2018, 07:46:41 AM »
Just a thought before you get too far in, you said you bought the cylinder set which should have included the valve chest. Check the length of that to make sure it will machine to 2.25" as if it is going to end up shorter that would look odd. New chest should not have the bit at the top for the valve rod as it has changed to a separate part.

Back to the question of ports, it depends on the particular engine, about 2/3rds only have the inlets but the remaining 1/3rd also have the exhaust cast in. Don't forget to poke some wire down the ports to remove any remaining sand.

Offline john mills

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Re: Little and large - building 2 vertical steam engines.
« Reply #97 on: May 21, 2018, 08:37:07 AM »
The valve rod   and piston rod length may need adjusting to siut.
Have they just made the same cylinder casting for the no4 and no 9.?

Offline Jasonb

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Re: Little and large - building 2 vertical steam engines.
« Reply #98 on: May 21, 2018, 10:25:51 AM »
Or more likely you have been sold a No9 Cylinder set which is for a 1.5" stroke engine rather than a No4 Cylinder set which is 1.25" stroke. Was it still in its packing?

Possibly they now just use the one casting but I've not seen a new No9 drawing to be sure.

J

Offline Gas_mantle

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Re: Little and large - building 2 vertical steam engines.
« Reply #99 on: May 21, 2018, 01:23:24 PM »
Thanks guys,

It is a no9 casting (the letter s on the chest cover is for a horizontal) I'll have a bit of a think about things as it may be I can increase the stroke very slightly if I can accommodate a larger crank throw.

The valve chest doesn't have the cast part to take the free end of the valve rod

It will be a minor miracle if this thing ever works with all these mismatched parts and a drawing doesn't suit the parts I have  ;)
« Last Edit: May 21, 2018, 01:29:24 PM by Gas_mantle »

Offline Jasonb

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Re: Little and large - building 2 vertical steam engines.
« Reply #100 on: May 21, 2018, 01:30:31 PM »
I did think about increasing the stroke, if you do so you will need to make sure the big end does not hit the bottoms of the standard, the trunk guide is long enough and that the conrod does not hit the ends of the trunk guide when at a steeper angle.

I have found the last of those to be the most common problem area when drawing up the 24series and also the big Tidman was very close so lots of adjustments to the cad drawing and turning the engine over on the screen to check clearances.

The later 2007 drawing has details of the valve rod guide ;)

Offline Gas_mantle

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Re: Little and large - building 2 vertical steam engines.
« Reply #101 on: May 21, 2018, 01:36:08 PM »
Thanks, I'll look into it before I cut the crankshaft.

Do you see any problem in not having the valve rod supported at the top ? I don't think the valve chest wall will have sufficient thickness to drill the required depth.

Edit - forget what I said, I see what you mean about the new drawing having a separate guide now  :wallbang:
« Last Edit: May 21, 2018, 01:39:24 PM by Gas_mantle »

Online Jo

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Re: Little and large - building 2 vertical steam engines.
« Reply #102 on: May 21, 2018, 02:33:17 PM »
I have copies of the No 4 drawings with the cylinder shown at 2" and 2 1/8". My No 9 Drawings show the cylinder at 2 1/8". The original cylinder casting has positions to allow the draincocks to either go at 90 degrees to the valve face or opposite the valve face to allow it to fit either No 9 or No 4 engine.

Maybe Stuart were told their later undersized castings were too small to make to their drawings  ::)

Jo
« Last Edit: May 21, 2018, 02:45:42 PM by Jo »
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Offline Gas_mantle

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Re: Little and large - building 2 vertical steam engines.
« Reply #103 on: May 21, 2018, 03:09:27 PM »
Jo that looks to be the same casting I have and is a 4 or a 9 in new money.  :headscratch:

Just as a matter of interest how old was the casting kit you made your no9 from, what is the stroke length ?

Online Jo

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Re: Little and large - building 2 vertical steam engines.
« Reply #104 on: May 21, 2018, 03:24:56 PM »
The stroke length is different on the No 4 and the No 9..... Even ones with the 2 1/8" drawings.

I had a similar problem with the 5A drawings: the Swan has slightly longer cylinders  ::)

Jo
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