Slide Valve Cylinder Castings

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jlakes85
Posts: 228
Joined: Thu Feb 23, 2012 6:07 am

Slide Valve Cylinder Castings

Post by jlakes85 »

Here is my first attempt at having my cylinder pattern cast. I had all the power and exhaust cores cast in. They didn't come out too bad, but I wanted to know if anyone had any experience with regards to the allowable fudge factor for the spacing between the ports. The plans do have a provision for a valve guide/plate, which will be machined out of cast iron, but if im already OK I would rathwr do without. Thoughts? Let me know.

-jlakes85
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20200229_092541.jpg
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Marty_Knox
Posts: 1724
Joined: Thu Jan 09, 2003 6:50 pm
Location: Michigan, USA

Re: Slide Valve Cylinder Castings

Post by Marty_Knox »

Looks like you have big ports. What is this for?
jlakes85
Posts: 228
Joined: Thu Feb 23, 2012 6:07 am

Re: Slide Valve Cylinder Castings

Post by jlakes85 »

Hi Marty,

This is for a 5" scale 15" gauge engine.

Regards,

John
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ChipsAhoy
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Joined: Wed Feb 18, 2015 12:23 pm
Location: Arizona

Re: Slide Valve Cylinder Castings

Post by ChipsAhoy »

I have plates made for my, yet unfinished engine, because of an error I did while machining. We stewed over it a long time weighing the plusses and minuses. Could find no minuses, (sense it was already screwed up) a plus was that down the road, no machining needed to the cylinder at rebuild time. Hense, when I made the "fix", I made spare set. If you need a pic... I can put one up here.
PS, I can offer this... next time I open the ports on a cylinder, I will plunge down with the end mill, make ONE pass and withdraw...I'll not make a return pass. (This ought to draw some smoke out).
Scotty
FKreider
Posts: 338
Joined: Fri Feb 02, 2018 8:44 pm
Location: Massachusetts

Re: Slide Valve Cylinder Castings

Post by FKreider »

Not sure what the plans call for with spacing but the ports look OK to me. Can really only tell for sure after you machine the slide valve surface and see how it looks.
-Frank K.
super7b
Posts: 94
Joined: Wed Oct 29, 2008 12:19 pm
Location: Beckingham, Lincolnshire, England

Re: Slide Valve Cylinder Castings

Post by super7b »

You will be better using a slot drill rather than an end mill.
L
jlakes85
Posts: 228
Joined: Thu Feb 23, 2012 6:07 am

Re: Slide Valve Cylinder Castings

Post by jlakes85 »

Hi Frank,

Spacing between ports in supposed to be 5/16, which is the same width as the power ports. Exhaust port is supposed to be 1/2 inch wide.

-John
Mike Walsh
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Joined: Sun May 06, 2007 10:14 pm
Location: St. Louis, MO

Re: Slide Valve Cylinder Castings

Post by Mike Walsh »

Did you incorporate machining allowance?

Given your ports being 5/16", I would say you would probably want 3/16" wide ports, as cast... Then for teh exhaust port, 3/8" as cast... So your cast spacing should be 7/16" between ports... It also looks like your cores may have broken, due to the odd shape of the left hand shape.
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rudd
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Location: savannah ga.

Re: Slide Valve Cylinder Castings

Post by rudd »

ChipsAhoy wrote: Sat Feb 29, 2020 6:47 pm I have plates made for my, yet unfinished engine, because of an error I did while machining. ......
Scotty
How did you secure the false seats to the castings?
jlakes85
Posts: 228
Joined: Thu Feb 23, 2012 6:07 am

Re: Slide Valve Cylinder Castings

Post by jlakes85 »

Rudd,

There were core prints for each port, about 2 inches tall, 2 degree taper on each side. On the cylinder bore side, i left about 2 inches of extra length for a core print. The exhaust passage was the most concerning, as one side dead ends within the cylinder, leaving only the valve face side for a print. I think the foundry guys glued that core in.

-John
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ChipsAhoy
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Joined: Wed Feb 18, 2015 12:23 pm
Location: Arizona

Re: Slide Valve Cylinder Castings

Post by ChipsAhoy »


How did you secure the false seats to the castings?
The steam chest bolts go down thru the plate into the cylinder casting.
Scotty
holtSteamer
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Joined: Mon Jan 21, 2008 6:13 pm
Location: Menifee, CA

Re: Slide Valve Cylinder Castings

Post by holtSteamer »

Here are some good pattern photos to reference regarding your exact casting outcome.
Attachments
Cylinder Pattern (1).JPG
Cylinder Pattern (2).JPG
Cylinder Pattern (3).JPG
Cylinder Pattern (4).JPG
Cylinder Pattern (5).JPG
Cylinder Pattern (6).JPG
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