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Steam locomotive connecting rods
https://www.rypn.org/forums/viewtopic.php?f=1&t=46503		 Page 1 of 1
Author:  kevin kohls [ Tue Apr 26, 2022 7:08 pm ]
Post subject:  Steam locomotive connecting rods
In the glory days of steam the great American locomotive companys: Baldwin, ALCO, Lima, and others; PRR for example forged their locomotive drive rods from a rough billet of steel forged on a drop hammer with highly skilled blacksmiths, followed by skilled machining.
With modern steel and processes how has that changed ???

Kevin K.
Author:  David Johnston [ Tue Apr 26, 2022 7:24 pm ]
Post subject:  Re: Steam locomotive connecting rods
My experience is with axles, not rods, but a very similar process. Today they start with a much higher quality steel. The blacksmith is sitting is a sound proof air conditioned room running his CNC forging hammer. When the appropriate reduction is achieved the axle heads for the machine shop where CNC lathes and grinders finish the axle. After heat treatment it is off to QA where the axle is inspected with equipment that is far superior to anything available 50 years ago. Todays railway axles are superior to anything ever made in the past. I am sure the same is true of rods.
Author:  softwerkslex [ Tue Apr 26, 2022 9:09 pm ]
Post subject:  Re: Steam locomotive connecting rods
There was a thread on this years ago. The builders themselves started discontinuing forged rods and using rods from solid bar in the last few years of production. The high quality and low price of solid raw stock just made it more economical than forging the shapes.

Forging makes sense when the source material is expensive. When the source material is cheap, but of high quality, then cutting from solid is more cost effective.
Author:  Stationary Engineer [ Tue Apr 26, 2022 10:14 pm ]
Post subject:  Re: Steam locomotive connecting rods
Stockton Locomotive Works has just machined a set of rods for a 3ft. gage Crown locomotive from 4140 steel.
Author:  Faller? [ Wed Apr 27, 2022 9:38 am ]
Post subject:  Re: Steam locomotive connecting rods
There is a "Forging" step somewhere in the process; the "Raw" billet was probably forged after several heating/tempering cycles; this is required for the metal density and grain structure to reduce the prospect of cracks etc.
Author:  Kelly Anderson [ Wed Apr 27, 2022 1:27 pm ]
Post subject:  Re: Steam locomotive connecting rods
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Author:  Faller? [ Wed Jun 01, 2022 2:47 pm ]
Post subject:  Re: Steam locomotive connecting rods
Building Steam Locomotives 1930s Trains Railways Educational Film S88TV1

This Video shows forging rods at the Crew Works in Britain in the '30's.

The narrator says the raw billet is heated and forged 5 times.

The part of making the boiler is equally enthralling! Heating and pressing out the various sheets. They show the "Throat" sheet, which is a very complicated piece, being made. The boiler has a Belpaire Firebox but they don't show the "Roof" sheet being formed which is equally complex.

The guys all know their job but I can't help wondering how busy the Nurse's office on a given day!

Thanks
Author:  kevin kohls [ Wed Jun 01, 2022 3:15 pm ]
Post subject:  Re: Steam locomotive connecting rods
Amazing films and skills involved. I know from collecting hundreds of BLW photographs that they cast up patterns to form the firebox sheets of different size boiler shapes and sizes. After all, BLW was a skilled machine tool builder, especially when it came to test instruments; large and small.
As a side note, In the 1980's I wrote the late Charles Brown who worked at BLW and later FM. He told me that when steam construction was finished at BLW they burned all of the wood patterns in a huge bonfire near Essington Ave.. Patterns that dated to the 1870's. It took TWO WEEKS to burn them up !!! If only we could turn the clock back.

Kevin K
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