Hello,

Through searching on YouTube or this site, I have not seen a good description of the quartering process.

If I missed a thread in RYPN that has described this, please forward a link.

Please describe the quartering process. To me it prompts a few questions.

1. Driver Center and Axle Keyways - In my experience in broaching small bore keyways it never came across as an accurate process. Obviously large bore key ways are done with a shaping machine? For the shaft, even the best index head 90 deg offset is basically a "rough" start?

2. Quartering Machine - please confirm if final machining occurs last, once all assembly is done, including axles pressed in hubs, crank pins pressed in, tires mounted, etc? It seems to me, after all the heavy pressing and possible distortion, this would be the only way crank pins can be machined accurately.

3. Final Accuracy - in reality even with a quartering machine, how accurate are the final pin centers from one side to the other? Assuming it's less critical for plain bearing connecting rods but would roller bearing rod locomotives need even more quarter accuracy?

4. Matched Sets? - regardless of the angular accuracy of the quartering machine are all the final cuts of the crank pins done on one side of the driver set? Meaning if they are off slightly, they are all off the same amount?

There are discussions on YouTube for live steamer driver quartering however for that scale it is possibly less of an issue compared to full scale locomotives with a 28" stroke for example. To me the quartering errors would magnify significantly.

Perhaps my inquire is obvious to many of you but would really curious on the pricess.

Thank you in advance!

Randy

One of the best descriptions of the quartering process I've ever found was a three-part article in the WW&F Newsletters. Check out the July/August 2013, September/October 2013 & the January/February issues.

http://forum.wwfry.org/index.php/topic,1454.0.html

Interesting questions and hope this thread takes off with some good discussion and information on the subject. I am not a master maniac that understands all the finer details. Much more of a Master Mechanics helper. But I did get involved in a project where some of this was addressed on a smaller 70 ton logging mike. Again I cannot talk about the dozen or so I was involved with as there was only one.

The owner contracted a machine shop in Milwaukee to turn his wheels and make and install a new main driver axle. This was one area I disagreed on. I would of sent the work to a tried and true wheel shop. Hind sight is 20/20 for all of us. In hind sight the owner agrees too. As it turned out this set the project back a while. The shop seemed like they did not want to fit the new axle? When the wheels returned finally, one of MC former CMOs checked the wheel dia which were not the same on the four wheel sets. Two had to go back for further machining. The axle they made and the wheel centers which were rebored and keyway cut seemed ok. The original bores were tapered if I recall. So they made the keyways and keys for the wheel center and do not recall hearing of any problem there. We ended up installing the axle ourselves with dry ice and ovens for the wheel centers. The owner did not have that shop cut the key ways for the eccentrics {Stephenson Valve Gear}. It was explained to me it was critical and the owner wanted the keys cut as close to right as possible. Sounds like it is easy to make mistake where it needs to be? Think Kelly shared a picture of an offset key to compensate for the miscalculation on one in their shop or a repair on someone elses? After the majority of the machinery was back in place we attached the eccentrics to the axle in their final resting spot on the axle. Then we set the valves and eventually marked the keyway on the axle. I am sure there are other ways to do this but that is what we did. Frustrating as the eccentrics moved around at times so we spent a lot of time marking and remarking our settings. We then borrowed a portable keyway cutter, one of the most super cool machines I have seen yet. J.Ryerson 1906 Pat date key way cutter. Had been in Dick Jesens collection at one time. The owner ram rodded the project and I only tried to help as a second set of hands. He nailed it perfectly in the end. Some of these projects would of been much easier but neither of us had ever done some of this work before so things took us longer. He had very little adjusting to do on the eccentric knives {think that is what they are called}. The engine is running fine in Oregon and is super square so his work on the valve gear I think could be described as "tried and true". If there is a way to figure out the exact placement of the key ways both on the wheel center and in this case eccentrics I can't say. But this is what we did and it worked. I can assume on paper it could be worked out by a qualified engineer or machinist, but above my ability x 10. This is professional work and not to be addressed by amateurs like myself. It wasn't and I only helped. Know your limitations. The owner talked to many people as we went along so he had help from professionals that were not new to this type of work. But in the end we did the work "in house".

The axle and keys fit the wheel bore and keyway perfectly and far as I know there was no problem with the orientation of the crank pins. For us it was rather dicey as none of us had done this type work before. Way above my personal ability to comprehend all the finer details.

Question: Am I wrong to understand that split bearings will allow for adjustment of the crank pins quarter if needed? Of course if the quarter is too far off or the bearings are worn so far that would be negated and further work or replacement would be necessary? I could see quartering on solid or roller bearings be way more critical than split bearings on older locomotives? So I ask?

In many of the videos of the UP #4014 she had a clank that sounded bad. This was on her midwest excursion and I presume what ever that was, was addressed? Not a lot of break in time before she went "live". Regards, John.

Not relating to preservation, but to larger-engine practice:

It was my understanding that large modern engines did not employ keyways of any kind, relying entirely on the axle 'fit' characteristics to prevent movement either slipping under thrust 'out of quarter' or shifting on the axle. As explained to me, keys weakened both the wheel center and the axle itself in ways highly invisible to NDT, and offset keys added very little to the effect as they required the wheel to be pressed off and then on anyway.

For eccentrics and valves, some form of offset key represents a relatively easy way to do fine adjustment on how the heavy (split) eccentrics themselves bolt up to the axle, without involving a heavy interference fit (which obviously is unattainable cost-effectively) while assuring the necessary precision (sometimes, historically, to 1/128" at reference datum near the valves through the linkage) as secured. That in turn precludes having to smith the eccentric rods or tinker with rebushing their ends to adjust final valve events. But none of this properly applies to any large radial valve-gear-equipped engine with the exception of a couple of experimentals.

My understanding of the advantage of a quartering machine was that it provided heavy permanently-crossed ways upon which machining heads for the pins could be installed to have easy 'centering assurance' but with the ability for radial distance along the ways to be adjusted. The pins, within limits regardless of their as-pressed angular relationship to each other, would then be cut, slightly eccentrically from their nominal centers, to perfect 90=degree relationship of the bearing surfaces to each other. You'd need heavy adjustment or an additional 'slide' to accommodate a 3-cylinder engine, and there would be something analogous to finish-machine the journal of an inside crank for the third cylinder main (modern American practice deprecated three-cylinder power, and the need to precisely align outside masses with inside crank position didn't come along until after the three-cylinder era was substantially superseded, so special machines may have been built but did not become popular enough to pay for their development and tooling costs to produce).

The PRR T1 is an unusual case in that its main pins are spaced at a different radius from the side-rod pins, and a quartering machine as above facilitates making and if necessary finish-grinding the pin to multiple diameters in situ. (These pins take nothing but roller rods, so the fit and surface finish are made accordingly) Note that in the absence of such a machine, both the fit of the pin in the center and the relative quartering would have to be made precisely, which is likely to be difficult in practice, whereas finish-machining in place is relatively simple.

There are several potential ways to make a frame for a portable pin-cutting setup that would permit the 'emulation' of a quartering machine in the field, probably to good precision if conducted in a climate-controlled space. Since I believe machines for on-the-locomotive pin machining (and perhaps even flamespraying buildup or similar technology) are already available for lease or rent, adding a quick ability to 'cut to quarter' ought to be valuable in a number of circumstances.

A fascinating discussion. I Googled Rynearson key way making machine and found this: https://www.practicalmachinist.com/vb/a ... ndex2.html
The pictures aren't too clear but scroll down to comment #22 and click on the address. Fascinating stuff.
Ned

Sorry Randy if I wandered off to far from your intent. I thought it was related enough to add.

nedsn3 do not know why those old pics are now so blurry on PB who I no longer use? Tried to post my original pics of the Ryerson machine but they won't take to this sites photo loading and I do not know how to shrink my pictures to where it will take them. You of course can rent new modern machines that do the same thing but get out your check book as the rent had nearly got to be the price of a new machine. Or at least it was in 2011/2012 when I looked into it. Unless you do a lot of that type of work it is hard to justify the purchase price. Maybe Harbor Freight is now selling these cheaper?

A wheel shop like Strassburg or Chattanooga might be able to justify the expense of specialty machines, your local museum not so much. So we beg, borrow or steal a way we can get it done. Or have some one write a big check for us and pay someone to do it for us. Regards, John.

No criticism intended John. If you click on the address in comment #22 you will get a clear picture of the device and a nice explanation too.
Again, IMHO this is a great subject of discussion. Thanks for starting it.