Model Engine Maker
Supporting => Engine Ancillaries => Topic started by: sbwhart on July 30, 2012, 02:15:13 PM
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I asked a ? about cylinder drain Cocks and you guys came up trumps with the answer, that enabled me to draw up some simple automatic drain cocks for fitting to my loco. A drawing of the cocks is attached.
So now to make them first job the body this is simple enough to do machine a length of brass to the required OD enough to make all the cocks required and part off to all the same length.
(http://i431.photobucket.com/albums/qq32/sbwhart/Simplex/131_1923.jpg)
Then chuck them up one at a time drill through No13 drill and tap each end 7/32"*40 ME
Set the mill up to drill a 3mm hole part way through to attache the T peice using the vice stops helps with this. and with a slot drill mill spot a small flat.
(http://i431.photobucket.com/albums/qq32/sbwhart/Simplex/131_1926.jpg)
Thats that bit done.
Then turn up a length again to do all the T peices required and thread 1/4"*40 ME and part off to required length, put a small centre in each one and at the other end turn a small pip a tight fit in the 3mm hole in the body, press them into the body making shure they sit down square on the flat.
(http://i431.photobucket.com/albums/qq32/sbwhart/Simplex/131_1930.jpg)
Then turn up the two end caps
(http://i431.photobucket.com/albums/qq32/sbwhart/Simplex/IMG_1087.jpg)
sorry about the poor pic but used the wifes camera whilst mine charged up and didn't quite get to grips with it.
The parts
(http://i431.photobucket.com/albums/qq32/sbwhart/Simplex/IMG_1089.jpg)
Silver solder the T peices to the body.
Drill through the T peice into the body this is easy to pick up on the centre drill hole particularly if you have left the mill set up
(http://i431.photobucket.com/albums/qq32/sbwhart/Simplex/131_1932.jpg)
Set the ball onto its seating by giving it a sharp tap with a hammer throw the ball away and replace with a new one after this as you'll knock it out of shape.
And this is where they fit on the loco
(http://i431.photobucket.com/albums/qq32/sbwhart/Simplex/131_1938.jpg)
I have a few unused bodies left if any one wants to try them just let me know what size you're cylinder is tapped and I'll finishe them of and post them.
I just have to keep my fingers crossed know that I've drawn it up correct and that they work.
Stew
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Nice Stew those look good on that cylinder. Thanks for the photos.
Dan
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Nice write up pics there Stew
now lets hope they work as planed note the may not perform as you would like on air but as you well know steam is a different animal
Stuart
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Good going Stew :)
I'm curious as to how well these work... And how they scale; I'll have to try them on a small engine one day.
Kind regards, Arnold
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Arnold,
They are available for G1 live steam engines so they work even in very small sizes. Just need smaller drills and a smaller ball.
Dan
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Yo Stew, your drawing is coming through as a blank page here
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OK with me Tel.
John
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Yo Stew, your drawing is coming through as a blank page here
Hi Tel:- checked things out this end and all OK
Stew
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Good going Stew :)
I'm curious as to how well these work...
Kind regards, Arnold
So am I :ROFL:
Stew
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OK with me as well.
For anyone else having trouble, I have converted it to a standard image below.
John
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Stew, I must be missing something here. What makes the ball go from the closed to the open position?
Bill
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Thats something I also had problems getting my head round Bil :thinking:l,
I think what happens is that when you get water condensing out into the cylinder it builds up a back pressure that lifts the slide valve off the ports causing a pressure drop that allows the ball to drop off the port and allow the water to be ejected, when the waters gone the slide valve seals, presurising the sytem and sealing the ball.
I've seen these type of Cocks work so I know they are effective, but I'll stand correcting on how.
Thanks for your interest
Stew
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Without cylinder pressure, the ball will fall from the seat; even with the cock full of water. At that point, water in the cock and cylinder will drip out and most will be cleared. With steam into the cylinder, the ball will be "washed" toward the seal, eventually mating up and pressurizing the system.
Another design would have two balls with a seat at each end so that if the cylinder is on a grade rather than level, at least one of the balls will be depressurized and allow the water to exit. It's probably unlikely that a grade steep enough to block the single valve style would be found on a rail line though :Lol:
Alan
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Ah! new thread I wondered why I'd not been pinged with these updates
PM sent Stew
Pete
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A simpler solution which is also better for scale models, especially small ones, is to install the ball valve in the bottom of the cylinder wall ends, then you don't have to make separate fiddly devices.
This method is shown here:
http://www.modeng.johnbaguley.info/locos/25inch/A1/A1-2.htm
- bottom of page.
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Hi Stu,
My Dad is about to launch into making one of your drain valves, why only 1 you ask, well he's fitting it to the steam operated brake cylinder on his loco & there is only 1!
The reason, currently the steam valve acts as both steam to, & HOT condensate from the cylinder, which ends up on his fingers! Told him he needs to harden up a bit, but at 87 he said he was past that!
Anyway the reason for replying is that on printing out the drawings, Thankyou very much for posting, I spotted that you had spec'd 7/32 x 40 ME on the body for the plugs BUT 1/4 x 40 ME on the plugs! I thought you may want to update the drawing so somebody doesn't get caught out.
Thanks again for posting the drawing, hopefully in due course I can report the out come.
Cheers Kerrin
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Thanks for the heads up Kerrin, hope your dads build goes OK
Stew