Machining Side Rods - Allen Mogul - advice needed

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Bruce_Mowbray
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Re: Machining Side Rods - Allen Mogul - advice needed

Post by Bruce_Mowbray » Thu May 08, 2014 1:35 pm

On most full sized drawings from "back in the day" materials were rarely called out. One would have to go to a list of standard materials buried in the makers standard practice manuals. If the customer were to specify a non standard material in their order sheet, a "Question customer" flag would go up and a series of correspondences between the customer and builder's engineer would ensue.

Each of the big builders had their own version of a standard practices manual. Each had their own idea, and usually a good reason behind it, of what material should be used where. Some materials were referenced by vendors product name. Some used (very) old names for certain alloys (common with babbits) . All of those manuals are very interesting reads.

Of the 4 big builders manuals that I use at work, most rod brasses are made of what is called "hard" or "Medium hard" bronze. Some few provide an actual alloy. I would question the application or babbit in rod brasses as this material squeezes out quite readily especially under the pounding conditions of rod brasses. I did see one example where babbit slugs or strips were cast into the bronze. Possibly the babbit tends to provide a little more lubricity to the bronze as the bearing wears.
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Springville & Southern RR
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steamin10
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Re: Machining Side Rods - Allen Mogul - advice needed

Post by steamin10 » Thu May 08, 2014 5:06 pm

As it was explained to me, Early rod ends with the take ups, could be easily replaced and cast in the round house in babbit, with little skill. Several grades of hardness were, (and are) available. A few swipes with a file and shimming, and you were ready to go. This was true for a rod that failed to get oiled on time, as the heated journal would not score the pin but could be easily refitted. Not so with hard bronze, as the heat generated would gaul the steel pin and give that plowed ring effect. A brass (bronze) could not be just filed in, it had to be machined to fit. Of course the constant greasing and oiling at station stops, kept washing the collected dirt out of the moving parts. ( Big engines had high parts loadings that were a factor too!).

It was part of the operational lore of steam, and it changed in detail over time, until the late 40's when full roller chassis became popular.
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Fender
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Re: Machining Side Rods - Allen Mogul - advice needed

Post by Fender » Thu May 08, 2014 6:09 pm

There's a scene in the great 1961(?) movie "The Train" where Burt Lancaster pours babbitt metal into a burned-up main rod bearing, then files the babbitt, before re-installing the main rod onto a French locomotive.
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steamin10
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Re: Machining Side Rods - Allen Mogul - advice needed

Post by steamin10 » Thu May 08, 2014 7:20 pm

Yep, thats pretty much it, until the early mid 30's, when the weights of the engines went way up. The railroads worked it both ways, keeping the repairs easy to keep the older workers, and embracing new technology on mainline engines of the last coupla generations to keep labor costs down and gain for efficiency.

European engines, are generally smaller because of the older track clearances, and babbit bearings lasted there for simplicity, long after the behemoths here were all roller bearing.

( I dont know the better history of European engines, or all the changes here, so there are major exceptions to the developmental history I put forth here. I have a master inspection book, that implies many of the changes, but is quite indefinate about many things.) I am but 62 and never worked in a round house, only at one museum. Steam had ceased to be King of the rails, when I was a knee high child.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.

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