# Is there a trick to Drain Cocks ?



## Nutz-n-Bolts (Aug 12, 2010)

One of my winter projects will be installing some drain cocks on my ruby that I want to have control over via R/C. I ordered some from Maidstone Engineering and they are quite nice but hang down too far. I was trying to keep from buying a mini lathe over the winter but I guess this is a good of excuse as anything.









The style I would like to use is where a stud with a hole in it ( well, 2 one vertical and on horizontal) is inserted in to each end of the cylinder and then a rod with 2 holes drilled through in the appropriate positions is then threaded through the two studs. Spinning the rod 90% opens the drain cocks. I may run the rods perpendicular to the track to give the drain cocks a more prototypical appearance.


My question would be: *Is there a trick to aligning the holes in the studs to allow the rod to pass though both*







I imagine any miss alignment would make it very difficult to the rod into the second whole with the tight fit required between the two parts. 


Thanks in advance!


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## dawgnabbit (Jan 2, 2008)

I don't have a clear picture of your situation, but I can tell you that the only sure way to get two tight-tolerance holes _perfectly_ aligned is to line bore or line ream them. Is it possible to install them and then ream both at the same time, with one pass of the tool?


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## Kovacjr (Jan 2, 2008)

So you are trying to make what accucraft uses on their locos?? They solder them in and you could use a rod as n alignment tool when soldering in. Yes they should be reamed and use a ground rod for the control. You should have a .0005 interference fit, If you know the accucraft you will know that they work for a while then are always open as they wear quickly from operation. DJB has pretty nice ones that are easy to install. I have since sealed mine up on the K28 as they were always opening themself from being too loose. Plus there are no levers left as when they fall down they get taken off at the next swtich stand.


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## Nutz-n-Bolts (Aug 12, 2010)

Thanks guys, I thought maybe I might have to install and then ream them both once installed. That is doable since I'll have it apart and the cylinders will also be off for that operation. 

Jason, I've seen the DJB ones but they are the automatic type that dribble as needed. I want ones I can open my self with r/c. They don't make those do they? You are correct I'm thinking of ones similar to Accucraft's . If I have them R/C'd do you think I will have the problems you describe? They won't be able to open unless I do it. 

I just love the look of a loco starting and seeing the steam come out each drain cock as thing start to move. I'm also planning to R/C the burner, throttle, johnson and I would like and WLDS servo water pump and probe set up if he can get a probe made to fit the Ruby. 

Thanks for the good advice guys!


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## Phippsburg Eric (Jan 10, 2008)

On a Ruby there is very little clearance between the cylinders and stuff along the track, though it should be sufficient. It also has small cylinders with small volumes of steam thus a small leak will have more effect than on bigger cylinders. My suggestion is to design a simple system and install it in such a way that you can remove it and go back to no drain cocks...do not try to solder it to the cylinders. make the whole works as small as you can, the holes for the drains as small as you can and the fits as precise as you can. 

On many small engines, there is a rod connecting the front and rear drain cocks on each cylinder. the ones I am familliar with operate with a wedge which acctuates the valve spindle. the rod between the front and rear has two wedges milled into it to operate both valves simultaneously. there is then a linkage between the cylinders so that all 4 draincockls open. this linkage is driven by a linkage from the cab. If you are radio controlling yours, you will end up with a similar arrangement. I would perfer to have the rod between each cylinder cock running parallel to the rail or it will catch on stuff under the engine and get damaged


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## elsiekillen (Oct 7, 2011)

i was supposed to ask thesame question on how to do it but i guess they just answered it. thanks.


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## Nutz-n-Bolts (Aug 12, 2010)

Eric, 
Good points about keeping things tight. I think my idea of running the rods across the track would be impossible since you would have to drill/ream the holes wile the cylinders were attached to the loco. Then if the frame was ever slightly tweaked it would through the alignment out. I can be happy seeing the rod running parallel under the cylinders as long as it means a set of operational drain cocks. I envision the lever/arm attached to the end of each rod pointing up in front of each cylinder and then a link running to a central arm hidden under the pilot. A wire shaft would go back from that point to the servo.


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## Phippsburg Eric (Jan 10, 2008)

Here is a phot of the cylinder of WW&F #10 a Vulcan plantation engine from 1915ish she is currently 2 foot gauge but was built as 30" gauge. she is just about the size of a Ruby if it were 1:20.3 scale

You can see her drain cocks and the simple linkage which operates them. the bar between the cylider cocks has two wedge shapes milled into it-- one for each cock. the bar is slid aft to open the cylinder cocks. you can see how the linkage is set up...it is quite simple. what you do not see is how the other side is actuated...I assume that the rocker arm in front of the cylinders pivots around a solid bar which reaches across the front of the engine to the other side and moves another arm.


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## Ray Cadd (Dec 30, 2008)

Something you might consider instead is to make or fit a rotary type drain valve to your exhaust lines, with the function of diverting the condensate outward, then re-routing it up the stack once things clear out. A servo can be set up to control such a device. Think something sort of like a reversing block or valve, as some small engines use. You just route a couple of exhaust tubes under the cylinders, pointing outward. Of course, it's all about space and fit. A friend of mine has an old Maxitrak Pearl (2.5" scale) that has such a setup. I didn't see what model engine you're trying to fit these to. A Ruby might be a pain. Modeling and functionality is often about compromise.


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