Slide valve

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Emfinger
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Joined: Tue Oct 01, 2019 3:30 pm
Location: Yucca Valley, CA

Slide valve

Post by Emfinger »

Hello all, I have been rebuilding (correcting a bad build) my 2-4-2 Columbia. The last issue is a incorrectly built slide valve.
It looks like the valve was purchased and installed without regard to the port measurements. When I look at the pictures at the following web site I get kind of lost.
http://www.modeng.johnbaguley.info/Valv ... Basics.htm
Given my port measurements is there someone who would be willing to make two slide valves for me? Or is there some place that sells them?

Thank you
Tom
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Bill Shields
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Re: Slide valve

Post by Bill Shields »

before any valve can be made...it is (sort of) necessary to know what lap is desired...
Too many things going on to bother listing them.
Emfinger
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Location: Yucca Valley, CA

Re: Slide valve

Post by Emfinger »

0.015" Are you indicating you could or would do this?
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Bill Shields
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Re: Slide valve

Post by Bill Shields »

And all the other dimensions necessary
Too many things going on to bother listing them.
Emfinger
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Re: Slide valve

Post by Emfinger »

Bill if you are not able or interested please don't ask for dimensions.
Gra2472
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Re: Slide valve

Post by Gra2472 »

Perhaps it would be best for you to solve this problem yourself. I suggest using emachineshop.com, the cad program is easy to use, and pricing is instantly available. I have used them in the past with good results. They are not cheap by any means. Good luck.
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Emfinger
Posts: 229
Joined: Tue Oct 01, 2019 3:30 pm
Location: Yucca Valley, CA

Re: Slide valve

Post by Emfinger »

I lack what it takes to design a proper valve. Most of the info. I have found conflict with each other.

http://www.modeng.johnbaguley.info/Valv ... Basics.htm

My ports may be too far apart ?? The valve rod only has 1/2" total movement. Later I post a picture.
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Bill Shields
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Re: Slide valve

Post by Bill Shields »

I did not say that I was not interested..but need information to make an informed decision.

Anyone building a valve need this information.

How wide are the ports..left to right?

How wide is the steam chest opening into which the valve must fit? How wide is the existing valve?

How high is the valve rod center line above the port surface?

How high is the existing valve...from port surface to top of valve?

What is the diameter of the valve rod? Is it threaded? If so..what is the thread?

How is the valve driven by the rod?
Too many things going on to bother listing them.
Emfinger
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Location: Yucca Valley, CA

Re: Slide valve

Post by Emfinger »

Duh !
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Bill Shields
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Re: Slide valve

Post by Bill Shields »

If this information is not available...then the request for someone to build you a valve is somewhat of a non-stzrter.
Last edited by Bill Shields on Sun Jun 13, 2021 5:12 pm, edited 1 time in total.
Too many things going on to bother listing them.
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Builder01
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Re: Slide valve

Post by Builder01 »

How has it been determined that the existing slide valve is not correct?
David Powell
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Re: Slide valve

Post by David Powell »

The explanation given in the link quoted is an excellent one. Only once those facts are understood can one make useful decisions about what size should the slide valves be made to or modified to, in order to obtain the best petrformance possible
While . at first sight,apparently simple. slive valves. together with valve gears more complex than slip eccentric gears, provide many interesting things to think about, and opportunities to get excellent economical performance of models
Regards David Powell.
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