Author Topic: High Pressure Steam Table Engine  (Read 25742 times)

Offline Jasonb

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Re: High Pressure Steam Table Engine
« Reply #240 on: January 29, 2023, 06:41:47 PM »
It should work, you could always file a slight curve onto the wedge so it sits nicely on the curved edge of the hole

Offline ettingtonliam

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Re: High Pressure Steam Table Engine
« Reply #241 on: January 29, 2023, 09:12:37 PM »
Having made 12 of these pesky things for the motion on 'Locomotion' the slot in the rod starts 1/16" from the end, so I should think yours needs to be about the same.

Offline Jo

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Re: High Pressure Steam Table Engine
« Reply #242 on: January 29, 2023, 09:29:40 PM »
Is the Locomotion 7 1/4" to the Reeves (David Piddington) drawings or 5" to the Atlier (Mark ??? German) drawings.

Jo
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Offline ettingtonliam

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Re: High Pressure Steam Table Engine
« Reply #243 on: January 29, 2023, 10:38:31 PM »
Its the 7 1/4" Reeves/Piddington version, although I do have scanned copies of the Atelier design, and hard copies of the 1928 ish Greenly 7 1/4" drawings. Mostly I work to the Piddington drawings, although it is useful sometimes to be able to cross check with the others. They all have 'issues' The Piddington valve gear design, as drawn, is unworkable, though his boiler, which I think Alec Farmer had a hand in, is the best of the 3. I don't think the 5" version would pull a person, but I'm hoping that mine will.

Offline Jo

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Re: High Pressure Steam Table Engine
« Reply #244 on: January 30, 2023, 03:59:32 PM »
To be able to calculate the potential lengths I can get away with for the side rod straps I need to start by finding out the total length of the rods. That means I need to do the crank rod first  ;)

First measure from the top of the crankpin to the underside of the table:



63.5mm  :thinking: Check the drawing the rod needs to be 59.5mm long:



That will leave 1.6mm clearance  :ThumbsUp:

Hold rod in square collet to take to length:



Mill an equal amount off either side to take to 6.35mm wide:



Check it fits:



and looks ok:



Decide how long to make this strap  :thinking:

Jo



« Last Edit: July 27, 2023, 03:41:45 PM by Jo »
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Offline crueby

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Re: High Pressure Steam Table Engine
« Reply #245 on: January 30, 2023, 04:19:15 PM »
Looking great!    :popcorn: :popcorn: :popcorn:

Offline Admiral_dk

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Re: High Pressure Steam Table Engine
« Reply #246 on: January 30, 2023, 06:27:41 PM »
Red 'n' Green - is that just to be able to tell Starbord from Port - or ...?

Good progress Jo  :ThumbsUp:

Per

Offline springcrocus

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Re: High Pressure Steam Table Engine
« Reply #247 on: January 30, 2023, 10:02:14 PM »
Red 'n' Green - is that just to be able to tell Starbord from Port - or ...?

Good progress Jo  :ThumbsUp:

Per
Not that way round, Per. The green starboard light is to the right on our stretch of water.  :Lol:
Looking good, Jo
 Regards, Steve
Member of a local model engineers society
www.stevesbritannia.co.uk

Offline Admiral_dk

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Re: High Pressure Steam Table Engine
« Reply #248 on: January 31, 2023, 01:13:17 AM »
It is absolutely the same way here (at least when I still sailed) - and / but, it never occured to me (when I wrote that) - that one could make the parallel you just did  :facepalm: .... but I see what you mean ....

It's just the way I think of the words in English - or should I say Danish .... as we almost always start by saying "Styrbord og Bagbord". You English has adobted Styrbord as Starboard, and they literarely means the same - but Bagbord more or less translates into Backside ....

Sorry for sidetracking your Thread Jo  :embarassed:

Per
« Last Edit: January 31, 2023, 10:54:54 AM by Admiral_dk »

Offline vtsteam

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Re: High Pressure Steam Table Engine
« Reply #249 on: January 31, 2023, 02:02:50 AM »
Still following with great interest!  :ThumbsUp: :popcorn: :popcorn: :cheers:
Steve

Offline Jo

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Re: High Pressure Steam Table Engine
« Reply #250 on: January 31, 2023, 08:53:16 AM »
Thanks Guys,

Per: The red shows the end of the strap that is over sized. The green is the correct width.

The big end strap drawing is correct: the distance from the centre line to the end of the strap is as shown 19mm. The side rods is still wrong and it looks like I have made my strap material too short  :wallbang:

Jo
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Offline Steamer5

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Re: High Pressure Steam Table Engine
« Reply #251 on: February 19, 2023, 04:51:46 AM »
Hi Jo,
Sitting in the arvo sun, sipping a beer doing a catch-up while away in the caravan, nice to see that the little grey cells are being challenged! Coming along nicely!
Comments a page or two back about sticky plastic handles….. find yourself some “Goo-Gone” a citric based sticky stuff remover, works a treat! We had a couple of camping torches which had become very sticky & were destined for the bin, gave the Goo -Gone a try & now they a nice to hold again.

Cheers Kerrin
« Last Edit: February 20, 2023, 12:09:21 AM by Steamer5 »
Get excited and make something!

Offline Roger B

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Re: High Pressure Steam Table Engine
« Reply #252 on: February 19, 2023, 07:44:14 AM »
Another elegant piece  :ThumbsUp:  :ThumbsUp:  The old engine designs were more stylish than modern ones  :)
Best regards

Roger

Offline Jo

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Re: High Pressure Steam Table Engine
« Reply #253 on: June 15, 2023, 12:45:20 PM »
I am trying a simple bit  :paranoia: to see if I can cope with making swarf again.

The steam chest and its cover come as two separate castings which need to be fitted together. So first job is to mill the top and bottom of the steam chest to just remove the casting marks flat as well as some of the part where the cover is to go to provide a datum. This allows me to measure the thickness and gives me an idea of how much spare there is:



So knowing I have the option of leaving the other cover at 3.18mm or 4mm thick I have chosen 4mm because I want the extra thickness on the steam chest later. Now I can do the cover. First a skim top and bottom to get rid of the casting marks, then take the top face so that the patterns are 1.5mm deep:



I now need to square up the outside of the casting on the patterned area and then mill the top and bottom. Before squaring off the sides



Now we work out how far is left to bring it down to size and where we want to take it from to keep the pattern central on the piece:



Castings are always much more interesting than using bar stock because you have to engage the brain before you cut anything :)

With the cover to width and length (it is still over thick  ;) ) I can measure where the centre of the valve spindle wants to be and then take the bottom of the steam chest to height:



Time to have a think:



The cover over hangs the bottom of the chest: this is ok as I still need to mill that step to the correct length and it still needs the bottom milling. It is best to mill the longer sides before the shorter ends as this makes it easier to square up the ends:



Thanks to that step in the top face of the casting I am using a parallel to provide a clamping surface so the casting is nice and secure. I am not taking it to width yet:



No there is another 0.9mm on either side to come off and I am about to check inside the steam chest for any nasties before milling those off. Not forgetting to have some lunch first  ;D

Jo
« Last Edit: July 27, 2023, 03:42:26 PM by Jo »
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Offline Charles Lamont

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Re: High Pressure Steam Table Engine
« Reply #254 on: June 15, 2023, 01:18:35 PM »
Very good to see you are making swarf again.

How will the butt joint be sealed?

 

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