Author Topic: Little and large - building 2 vertical steam engines.  (Read 10016 times)

Offline Ye-Ole Steam Dude

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Re: Little and large - building 2 vertical steam engines.
« Reply #210 on: November 03, 2018, 08:31:47 PM »
Hello Peter,

Looking real good at this point. I was not able to view your video?

Have a great day,
Thomas

Offline Gas_mantle

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Re: Little and large - building 2 vertical steam engines.
« Reply #211 on: November 03, 2018, 08:34:47 PM »
Thanks Thomas  :)

For some reason the video doesn't appear to have uploaded properly so I'm re doing it. It is only a 3min video explaining what I intend to do next etc but should be re posted shortly.

Edit - It should have uploaded now.
« Last Edit: November 03, 2018, 09:51:31 PM by Gas_mantle »

Offline gary.a.ayres

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Re: Little and large - building 2 vertical steam engines.
« Reply #212 on: November 06, 2018, 01:01:27 PM »
Great progress Peter. Looking good...

Offline Gas_mantle

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Re: Little and large - building 2 vertical steam engines.
« Reply #213 on: November 06, 2018, 02:26:07 PM »
Thanks Gary, I now have the valve chest partly made so hopefully I'll have it running in a week or 2  :)

Offline Gas_mantle

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Re: Little and large - building 2 vertical steam engines.
« Reply #214 on: November 08, 2018, 07:43:11 PM »
I'd really like to get the small engine up to the same build stage as the 'biggun' but as I'm getting close to being able to test run the no4 I've decided to continue with it first. Although the valve chest isn't quite finished it's well on the way so here is an update of where I'm now up to.

The valve chest casting doesn't have a raised boss to drill for a valve rod guide and I guess it isn't really essential but I'd like the finished engine to have one so I've decided to make my own. I was under the impression that no4 and no9 cylinder / valve chest castings were the same but as my casting has the 'S' orientated for a horizontal (no9) engine this may explain the absence of the valve rod guide boss.

Anyway enough of that, first thing to do is to square of the chest casting in the mill.



With the cover similarly squared off it's time to drill the 4BA fixing holes on both parts together. I kinda think an engine of this size could possibly benefit from more fastenings (maybe 10?) but the drawings show 6. so 6 it is. I'll mill out the 'S' later.



I hope this method will line up ok to drill into the cylinder casting  :facepalm:



Well with them drilled I may as well tap them



Drilling for the inlet flange I made earlier.



The valve rod needs to enter the chest at 3/8ths from the port face which isn't quite central to the casting boss but the intention is to machine the brass flange and the casting as a single unit so the finished result should be central. It is drilled and reamed at 5mm with an 8mm dia milled hole 7mm deep to accept the packing gland.



It wasn't practical with the tooling I have to drill right through the casting for the valve guide on the top face, so I drilled from above with a vice stop to hopefully pick up the same axis. It is then tapped at 1BA.



So with the 5mm valve rod in place I'm up to here.



It lines up ok but is a bit tight although I think it should be fine. The top (free end) of the valve rod needs turning down to a smaller dia (prob 3mm) and it will then locate in a drilled guide. I'd like oil to be able to get past the valve rod in its guide so assuming the rod is 3mm dia I'll drill the guide at 3.1mm and this hopefully will ease the present tightness.



It seems to be taking shape.



With a bit of luck I'll get the valve rod gland fitted and profiled, followed by the top guide and slide valve in the next day or 2. That should allow me to test how it responds to the valve before making the eccentric  :)

Offline Gas_mantle

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Re: Little and large - building 2 vertical steam engines.
« Reply #215 on: November 10, 2018, 09:14:48 PM »
I'm pleased to say I now have the valve and valve rod in place and things seem to be coming along.

The valve rod is 5mm steel turn at one end to 3mm where it will enter the guide (I didn't photograph making the guide but it is a simple turning and drilling job on a piece of hex brass), another  short portion is turned down to 4.7mm to thread at 2BA for the valve nut. I did wonder I'd need a steady whilst tuning but the deepest cuts are near the tailstock centre and the turning for the thread only involves 0.3 mm off the diameter so with very fine cuts things went well.



I'd already done the preliminary work on the valve rod gland to it was now just a case of bolting it in place then using the boring head in the mill to profile it along with the casting boss. There were a few hollows in the casting and to fully machine them out would have meant making the part thinner than I wanted so I chose to stop here then finish with a file and emery.



The valve block is the usual slide valve and is machined from a piece of brass, it needs a 1/2" x 9/16" pocket on the underside so once machined to the overall size the pocket is marked out. (the small hole is just a remanant of a previous operation in the in the piece of scrap and is of no significance)



The smallest slot drill I have is 3/32" and that coped nicely at machining the pocket.





To accommodate the valve nut and rod it's now just a matter of milling 5mm channels on the outer face



That then takes me to this point, it's a bit boxy compared to the one in the Stuart plans but it will never be seen and I'm happy with the critical dimensions



It fits ok an slides nicely so I think it will do the job. If need be I can always trim a bit off the outer profile to improve steam flow in the chest if it is too big to the point of choking the engine.



Digressing slightly and thinking forward I thought as I intend this engine to run on steam it would probably be a good idea to fit drain cocks, forum member Florian saw me mention them and kindly offered to sell me a pair of his homemade drain cocks at a good price. I bought them and I'm well impressed with the quality, they ought to give a nice finishing touch to the engine once fitted  :)






Not long now until steaming up  :)

Offline crueby

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Re: Little and large - building 2 vertical steam engines.
« Reply #216 on: November 10, 2018, 09:20:40 PM »
Thats quite a delicate bit of turning!
 :popcorn: :popcorn: :popcorn:

Offline Gas_mantle

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Re: Little and large - building 2 vertical steam engines.
« Reply #217 on: November 10, 2018, 09:30:28 PM »
Thanks Chris, I found that with a newly sharpened HSS parting blade it worked quite well, I managed to get the open end to 3mm dia to fit in the brass guide drilled to 3.1mm that seems to give a bit of allowance to stop the rod binding in the guide and allow oil into blind end.

Offline gary.a.ayres

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Re: Little and large - building 2 vertical steam engines.
« Reply #218 on: November 11, 2018, 04:10:39 PM »
Great progress Peter. Looking good!

Florian's drain cocks are little gems too.