Author Topic: Cylinder Drain Coxs  (Read 28280 times)

Offline sbwhart

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Re: Cylinder Drain Coxs
« Reply #15 on: July 25, 2012, 09:43:26 AM »
Pete

The reason I know about these types of cocks  :LittleAngel:   is a quite a few of the guys at the club run with them and are very happy with the performance. If I can get hold of the drawing from the absent member i'll pass it on.

Stew
A little bit of clearance never got in the way

Offline Dan Rowe

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Re: Cylinder Drain Coxs
« Reply #16 on: July 25, 2012, 01:16:58 PM »
Stew & Pete,
This link has a drawing of the type shown by Stuart and another type of steam operated cock.

http://www.chaski.org/homemachinist/viewtopic.php?f=8&t=86236&p=179074&hilit=drain+cocks#p179074

Dan
« Last Edit: July 25, 2012, 05:29:41 PM by Dan Rowe »
ShaylocoDan

Offline mzt

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Re: Cylinder Drain Coxs
« Reply #17 on: July 26, 2012, 02:12:30 PM »
sorry to be off topic stew but did you or are you  going to post on this site your simpson and shipson  build. i have the cylinder and piston build, coming along good so far. thanks jonesie

Stew,
sorry for the off-topic answer, but...

jonesie, where are the pictures???
Marcello
This is a fitting job,
not a production job that can be measured in.

Offline sbwhart

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Re: Cylinder Drain Coxs
« Reply #18 on: July 26, 2012, 05:51:25 PM »
Just drawn a drain cock up, don't know if it will work but worth a try.
 

 :thinking:

Drawing attached


A little bit of clearance never got in the way

Offline Stuart

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Re: Cylinder Drain Coxs
« Reply #19 on: July 26, 2012, 05:58:25 PM »
Stew

That looks a lot better than my CoC , should be Ok might take a bit of fettling to get it working as you would like at least there is not a mess of pipes around like my class 4 1/16 od steam lines and 3 /32 drains and one from the piston valve chamber



Stuart
My aim is for a accurate part with a good finish

Offline Dan Rowe

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Re: Cylinder Drain Cocks
« Reply #20 on: July 26, 2012, 07:18:10 PM »
Stew,
I finally located a drawing of one of these in my library. The reference is Live Steam July/Aug 93 author William Van Brocklin.

It is basically the same only the body thread is 1/4-32 not ME and the cap is drilled and reamed for the outlet. That is a nice touch as it makes machining the seat simpler. Not having to machine the seat in a hole was worth looking this up for me.

The bit I am concerned about is you have a 4.7mm bore which I am assuming is a 3/16 end mill to machine the seat with a 5/32 SS ball. This only leaves 1/64 clearance for the ball in the valve. Not much room for the ball to drop off and any tiny bit of dirt will gum up the works.

The design in LS has a 1/8" ball for that size valve chamber.

Another point the article made is this type of drain cock should only be used for D slide valves not piston valves.

I can make a sketch if needed.

Dan
   
ShaylocoDan

Offline sbwhart

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Re: Cylinder Drain Coxs
« Reply #21 on: July 26, 2012, 07:52:04 PM »
Thanks for the input Dan I thought about using a 1/8 ball so I think that is what I'll use instead of 5/32

Bit unsure what you mean about the seating in the cap  :thinking:

Stew
A little bit of clearance never got in the way

Offline Stuart

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Re: Cylinder Drain Coxs
« Reply #22 on: July 26, 2012, 08:23:01 PM »
I believe what Dan is saying  the body is drilled and taped through end to end and the seat is a hex union faced off to form the seat  with the plug at the rear


make making the valve seat on the lathe and not down a hole

I misread you drawing and as Dan stated the body bore need to be larger the ball should be loose

found this on the net and it shows the type that Dan has mentioned
My aim is for a accurate part with a good finish

Offline Dan Rowe

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Re: Cylinder Drain Coxs
« Reply #23 on: July 26, 2012, 08:28:01 PM »
Stuart beat me to the punch, and yes that was what I was attempting to say.

Here is my sketch.

Dan
ShaylocoDan

Offline sbwhart

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Re: Cylinder Drain Coxs
« Reply #24 on: July 26, 2012, 08:47:35 PM »
Got it  :ThumbsUp:

That is a lot simpler, I'll revise the drawing tomorrow

Thanks all

Stew
A little bit of clearance never got in the way

Offline Alan Haisley

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Re: Cylinder Drain Cocks
« Reply #25 on: July 26, 2012, 10:42:15 PM »

While reading this:

Another point the article made is this type of drain cock should only be used for D slide valves not piston valves.


I got to wondering just why it would work with a D valve but not with piston valves. Assuming it's a matter of timing, could someone explain just what happens  :shrug:


Alan



Offline Dan Rowe

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Re: Cylinder Drain Coxs
« Reply #26 on: July 26, 2012, 11:24:28 PM »
Alan,
They will work with piston valves. It was bad wording on my part.

The author actually said they were not recommended with piston valves. The way he said to use them was to crack the throttle and SLOWLY warm up the cylinders.

A heavy hand on the throttle and a lot of water flow will seat the valve. A D slide valve will lift off the seat to prevent hydro lock. A piston valve can not relive the pressure and that is the issue.

Dan
ShaylocoDan

Offline sbwhart

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Re: Cylinder Drain Coxs
« Reply #27 on: July 27, 2012, 08:01:33 AM »
Ok revised the drawing I kind of liked the idea of the ball sitting on a teat when its in the open position, but by way of an experiment I'll also make the other kind to how how it works.

Thanks for your inmput Guys  :cheers:

Drawing attached

Stew
A little bit of clearance never got in the way

Offline Stuart

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Re: Cylinder Drain Coxs
« Reply #28 on: July 27, 2012, 08:12:07 AM »
you will have the worlds largest repository of auto drain information at your finger tips very soon


Stuart
My aim is for a accurate part with a good finish

Offline doubletop

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Re: Cylinder Drain Coxs
« Reply #29 on: July 27, 2012, 09:48:16 AM »
Stuart

A few posts back something similar crossed my mind however "the worlds largest repository of auto drain information at your finger tips" is probably a bit more polite than my version


Behave Pete; too many Pinot's.  A very useful thread and Dan's link to Chaskis website leads to a whole lot more information.

Pete
?To achieve anything in this game, you must be prepared to dabble on the boundary of disaster.? - Stirling Moss

 

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