Here is a shot taken today (11/19) of the Underwood portable cylinder boring machine owned by Mid-Continent Railway Museum at work truing the right side cylinder of C&NW 1385. The photo was taken by Steve Roudebush, owner of SPEC Machine, Middleton, WI where the work is taking place. The valve cage above this cylinder has already been machined and work will then move to the left side. mld

Very Nice, good to see skilled folks applying the old tools of the trade.

Congratulations for mastering that beast of a machine tool.

Best if you keep the necktie wearing "boss" pretty far away from all them shiny "gear" things.

Great work, I bet if OSHA saw that they would have a stroke;

1) unguarded rotating machinery
2) no clear provisions for lock-out-tag-out
3) no clear lifting points (that must weight over the OSHA 40 lbs per person limit)
4) no chips guards to restrain metal projectiles
5) no dust containment method provided
6) no clear illuminated status lights to indicate error conditions
7) no load limits clearly stenciled on the machine
8) no "Emergency Stop" switch provided
9) might have over the allowed limit of lead in the bearings
10) too much VOCs in the paint
11) it is probably driven by fossil fuels...

Just kidding, very nice to see "old school" stuff applied in 2015.

Very Cool, Good Luck.

Cheers, Kevin.

Agreed this is a cool machine. To best of my knowledge this is the third steam locomotive the Underwood Boring bar has been used on {since being brought out of retirement that is}. There are other approaches but this is very portable and works like a charm. Put a air motor on it and after set up you become a machine tender and it just chugs away. The genius of design in these after market machine repair tools is outstanding. A marvel as much as the machines it was designed to repair.

Jim Eng, former CMO at MC was the first to take the machine out of the casket it rests in and put it together and use it. It first bored out the cyl on the Polson #2, then the Western Coal and Coke #1. Now CN&W #1385. Somewhat like a ridge reamer for removing ridges on cyl walls of infernal combustion engines. But much more cool. I remember looking at a large floor bar thinking it would work well for large cyl boring. It is much easier to "bring Allah to the mountain" than "the mountain to Allah".

Great pics, thanks for the update. Regards, John.

Would like to see video of this machine in operation.

I'm curious~ how much material did they have to remove truing this cylinder? Just a skim cut?
My reason for asking: if the cylinder bore is enlarged by boring, the piston doesn't fit the same as it did.

In an internal combustion engine, new pistons to fit the enlarged bore are installed.

What do they do in this case? Piston rings of a wider cross section and call it good?

Pistons of various sizes were made to "standard" oversizes on some lines. When the out of roundedness grew to certain limits of tolerance, the cylinders were bored out to the next stock oversize and new pistons and rings applied. Today, in captive steam-zoo service, we generally adapt the existing pistons with rings of larger radial dimension if the change is small, or build up the old pistons if not small also with new rings, or replace the pistons and rings complete if the bores are substantially larger. Once bored out to the same diameter as the counterbores, the cylinders can be sleeved with cast iron liners to start the process all over again.......

I've seen some very odd "adaptations" such as adding copper bolts screwed into the bottom OD of the pistons to make them "ride higher" in the bores. This didn't do too well. Wrapping the pistons and ring grooves with new material or building them up and turning true works better. In a pinch, you can try to work the rings into the out of round fit of the bores to provide a better seal.

If you replace the pistons, consider changing to a multiple narrow ring design rather than the two ring design - you will use much more of the steam for propulsion than blowby.

Dave I have a question for you or anybody with experience. If you opt or have to have new pistons cast is this a serious problem? I ask as most pistons are hollow to some extent and am not sure how hard it is to make new pistons or if a piston could be built/fabricated in layers so to speak versus casting new ones?

A privately owned locomotive I know of seems to have had its original pistons lost or accidently scrapped. The Cyl were bored out pretty well and not sure if they could of been built up or not, but unless they turn up sometime we will end up having to build or cast new pistons. This particular locomotive was very far out of round, by the time the cyl were cleaned up half the counterbore was removed. Not sure what the limits are for building up and turning down pistons.

Not trying to steal the thunder of #1385, but this may very well be a question connected to the original post as far as when to replace pistons and who and how does one go about it without a lot of rework and trial and error? I have often thought about this piston question and never asked anybody who knew for sure. The locomotive in question is not #1385 though. Not my project.

Regards, John.

Some were hollow and some were solid in smaller bore dimensions. Some were built up of components, some cored castings, some pretty high tech, actually...... I'd see if I could find the builders standards and practices book or even prints for similar locomotives from the same builder to work from to replicate the originals. Failing that, you can look at the Cyclopedias for design ideas, or start with a blank sheet of paper and figure out what parts of a billet you take off to make it look like the piston you need. There's a lot about piston design in RED DEVIL.

I'll attempt to answer at least some of the posed questions. Through some research and the generosity of many, we have many "standards, practices and shop practices" from both manufacturers and railroads although not a complete set from any one. This includes American Locomotive, Baldwin, C&NW (as stated on the original drawings), Santa Fe & UP to name a few. We have also been the fortunate recipients of the experiences of many within the industry today. Our general approach has been if standards or limits are stated on the drawings that becomes the governing statement.

How much out of round is "a lot"?, it is obviously a judgment call. In our case it was easily measurable so research was done as to how thin was "too thin" for the cylinder liner. The C&NW drawings called for "gun metal" cast liners for the cylinder as well as the valve cages. We then researched and found a standard that stated how much thickness could be taken away (based or original bore size) before the liner must be renewed. In our case both sides will require a bit more than a skin cut but will end up comfortably within the thickness limit after being made round.

The pistons for the 1385 are built up from 3 major components - The bull ring which has the ring grooves and the front & rear retainers which are bolted together in a large sandwich. The C&NW practice was to install a new, larger bull ring when necessary. It looks like we will probably be casting a pair of new bull rings but that is still under research. At this point I doubt we will change from the current 2 ring design which has proven itself in this engine design. While I don't discount the idea to strive for the best efficiency possible, that has to be balanced against the cost of redesign and possible failure. That being said, it is still a work in progress and subject to change.

I'd like to take this opportunity to thank all the folks within the industry that have been a help to this project so far. Many have been generous with their time, thoughts, opinions & experience. I dare not try to make a list for fear of leaving someone out. Please accept my thanks and the thanks of Mid-Continent. mld

Coincidently, such a video was recorded and just hadn't been edited and uploaded until now. Here you go... early access before it hits the MCRM steam status page.

https://youtu.be/h2NI_u0JIrw

J. Lentz

Jeff,
Thank you very much for posting the link. I knew it was lurking out there somewhere and am glad to know you got the time to finish it off. mld