The cylinders are mounted.....

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rwmorris
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The cylinders are mounted.....

Post by rwmorris » Mon Sep 08, 2008 8:44 am

Hey Group,

Well this was a major project...... These castings from MEG Steam were just about the hardest thing I have had to machine yet. But they are really nice and are finally mounted on the frame of the loco. One of the castings had a huge sand pocket inside and needed a sleeve machined up to correct that issue. They still need bolt holes and porting but the sizing, mounting, and boring is all done and dandy....

Have a look!

Robert M.
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gwrdriver
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Post by gwrdriver » Mon Sep 08, 2008 9:30 am

Used to be there was standing policy in live steam, and in fact by foundaries in general, bad castings were returnable for replacement. Is this not the case any more?
GWRdriver
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rwmorris
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Post by rwmorris » Mon Sep 08, 2008 9:56 am

I spoke with the guy at the foundry that cast these for Dougal Hubner, "i.e MEG STEAM," when he was in business and he agreed to send another for a replacement. However I gave it about 10 mins of thought and went with the sleeve approach because I already had so much time into the casting.... Plus it was fun the make the sleeve! I gave it about 0.002" thou interference and then put the cylinder in the BBQ on high and the sleeve in the ice box. What a thrill to drop it in and then have the two become one..... back in the lathe for finishing and I was done.....

Cheers,

Robert M.

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Fred_V
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Post by Fred_V » Mon Sep 08, 2008 11:42 am

a buddy at Ridge Club in Fl. built one of those. nice engine.
fred v
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Mike Walsh
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Post by Mike Walsh » Mon Sep 08, 2008 11:43 am

rwmorris wrote:I spoke with the guy at the foundry that cast these for Dougal Hubner, "i.e MEG STEAM," when he was in business and he agreed to send another for a replacement. However I gave it about 10 mins of thought and went with the sleeve approach because I already had so much time into the casting.... Plus it was fun the make the sleeve! I gave it about 0.002" thou interference and then put the cylinder in the BBQ on high and the sleeve in the ice box. What a thrill to drop it in and then have the two become one..... back in the lathe for finishing and I was done.....

Cheers,

Robert M.
Just a thought...

Wouldn't putting the cylinder in the BBQ actually REDUCE the diameter of the cylinder bore? Metal expands when heated up... Diameters (when heated) would become smaller than what would otherwise be exact (at room temperature)? My thinking is this way, but if I am wrong, please correct me!

Thanks,
Mike

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gwrdriver
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Post by gwrdriver » Mon Sep 08, 2008 1:05 pm

Robert,
I agree that sometimes, all things considered, including the challenge of doing something new, it's just as well to go ahead and use the casting as to bother with replacement. Not long ago I did the same thing with my 2X Tich cylinders, preliminary borings showed the iron to be rather brittle and granular (but a different granular than iron should be) and unable to take a good finish so I sleeved them. Otherwise they were OK.

Mike,
We've had this discussion before and not everyone is in agreement with what happens, but according to my sources a ring expands (or contracts) from its epicenter, the center point of its mass. In our terms, while the rim of a steel tire (a "torus") will expand slightly across its rim section when heated, thus reducing the theoretical ID, it is at the same time expanding radially but at a greater proportional rate, due to more metal in that direction, resulting in a net increase in the diameters.
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Bill Shields
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heating & holes

Post by Bill Shields » Mon Sep 08, 2008 2:10 pm

Initially, it is quite possible that the bore would shrink a bit, then as the entire casting got hot, would open up again.

We used to heat pump impellers - 24" diameter with 8" bores for the shaft.

If we heated everything up at once, the bore would shrink and we would have one devil of a time.

finally we learned to heat the OUTSIDE diameter FIRST, then slowly work toward the center and the bore would grow.

Always best to not be in a hurry and wait for things to soak

When I bored my Allen cylinders many years ago, I also found a bad spot and rather than collect on Gene's generous offer to send me new, it was easier to just sleeve it and be done with it.

Now, had I found the bad spot in the first 4 minutes of machining, I might have had a different attitude..

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rwmorris
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Post by rwmorris » Mon Sep 08, 2008 2:59 pm

Soak up time was key.....

The funny thing about the whole deal was that it took place at around 4:00 am.... I was not sleeping and the wife told me to get out of bed as I was driving her nuts with all of my fidgeting around.... This was about 2:00am... So I headed out and go hot on the lathe machining up the sleeve. I then placed the casting on a plate of steal so that the sleeve would only go flush to the back side. I turned the grill on high and left it for about 45 mins.... I didn't want to get to techy with the math by trying to calculate expansion and what not so I toss the sleeve in the ice box for good measure. I placed it in a wine bottle chiller when I took it out just to make sure I didn't warm it up with my hands and headed back out the the BBQ. As I pulled it out it quickly frosted up in the night air and I dropped it into the cylinder block. It took about 2 seconds for the moisture to disappear and that was it..... Together for ever.... If the neighbors only knew what I was doing with the BBQ at 4:00am!!!

I was so excited I really wanted to run back in and tell my wife but I refrained for several more hours before heading back inside and waking her up with the news....

Bill, I'm with ya on the machining time... If this would have happened on the first few passes it would be different but I had already sunk 2 days into this thing and I didn't really want to start over.

A side note about Gene's castings is that I also machined my pair for my next engine which is one of his American's and they cut like butter...... Super nice and a snap to machine. My shop is such a mess from the cast iron I figured I might as well machine as much as possible before cleaning up. The iron that Gene uses is way nicer than these castings.... These have been tough as nails the whole damn time.... Glad they are almost done....

Cheers,

Robert

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