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3D printed Shay, Engine design done and working Journals/Blogs
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Super User 157 posts MannsCreekRR Super User 157 posts
MannsCreekRR

its about time, this took way longer than I thought it would, but it is done and working well.  I still have a few details I am going to add (blowdown valves, oil cups, etc).

by the way, in case you did not know, the set of cylinders on a Shay is referred to as the "engine", just so there is no confusion.

when I started this project (printing the shay) I was originally going to use PSC parts for the engine, however I changed my mind and decided to print as much of it as I could.  changing the engine to use printed parts caused to have to redesign much of it, over and over and over.  I just about gave up on printing all the parts until I finally got it to work out.  The main issues I was struggling with were either the parts were too hard to assemble, or they broke when assembling, or they did not function.  It took what seemed like a hundred tries before I found that magic combination that was acceptable.

with the engine out of the way I can now print all the final parts and build the actual model.  The next posting you will see will be the finished product.

 

again, the following images are of the model parts just sitting in place, nothing is glued or screwed together

below, the engine is test fit to the opening, the small hole in the last cylinder marks the mount for the blowdown valves, all three cylinders will need a set of valves, the final cylinders will have the six required holes printed in them.  All these parts match the prototype pretty exactly, and as nice as "exactly" is to have it does cause fit issues on models, the space between the last eccentric link and the cab cutout was pretty critical, as the photo shows

AY%208-3.jpg 

below is the engine with the crankshaft, piston rods, and the valve gear installed.  those eccentric rods were a big PITA and was the major hold up, too thin they broke, to thick and they bound.

AY%208-6.jpg 

AY%208-5.jpg 

 

below you can see all the parts (so far) set in place.  The final cab has been redesigned for operating doors and separate window frames.  The tank (tender) will have a removable coal load so I can access the decoder without having to remove the shell.  I redesigned the smokebox to include the headlight bracket as well.  I painted the smokebox gray to see how the detail will hold up, I like it.  this is also a new frame design, which is a test print, I made a few adjustments and the final frame will be printed this week.  I print the frame in two major sub pieces which are joined behind the engine.  the two pieces are printed vertical with the pilots toward the build plate.  Printing them vertical makes them almost totally self supporting and requires a minimum about of supports.

AY%208-1.jpg 

for fun here are some digital images, I find drawings and renderings interesting to see.  The amazing part of 3D modeling and printing is that what you see on the screen is what is actually printing.

AY%208-9.jpg 

20102206.jpg 

20100100.jpg 20100245.jpg 

Jeff Kraker

Read My Blog
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laming Super User 3,962 posts
laming

Very Nice.

What scale? Appears to be at least O scale?

Andre
Kansas City & Gulf: Ozark Subdivision, Autumn of 1964
 
The "Mainline To The Gulf!"
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MannsCreekRR Super User 157 posts
MannsCreekRR

Yes, On3

The model is built to O scale with the gauge 36".

Jeff Kraker

Read My Blog
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laming Super User 3,962 posts
laming

Thanks!

I figured so.

Looking great.

Andre
Kansas City & Gulf: Ozark Subdivision, Autumn of 1964
 
The "Mainline To The Gulf!"
Reply 0
railman28 Regular poster 194 posts
railman28

just excellent

your Shay is so sharp. It really looks great.

 

Bob
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buckhornlogging New member 9 posts
buckhornlogging

Beautiful Build!

Really is impressive!!  I own a HO Bachman Spectrum and have seen how small these parts must be.  I'm curious about a few things: what material was it printed from what kind of printer was used and what was the source of the print file.  I've been around long enough to know the difference between "Easy" and "Simple"  There may be a few who may think such a project is "Simple" - download a file, enter it into a 3D printer then hit PRINT!  VOILÀ!!! Instant loco!!  Just because it MAY appear simple to some. it certainly ain't EASY! Thank you for sharing the fruit of your perseverance!! 
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Douglas Meyer Prolific poster 2,047 posts
Douglas Meyer

I just got home from a

I just got home from a vacation to Babcock state park.  And I can picture this thing running around up to Clifftop…

-Doug M
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MannsCreekRR Super User 157 posts
MannsCreekRR

Material, printer, and file source

I have tried a lot of resin and I have returned to mostly using Anycubic Black.  The rods are a custom blend of Anycubic black and some Elegoo ABS resin so the parts have a little more flex.  I have tried to use ABS resin straight from the bottle but the parts would warp too bad.  I have used some Siraya resin but they also warp when curing under the final UV light.  The mix of about 80% Anycubic Black and 20% ABS works well if I water cure them in a clear container in my UV cure chamber.  I do not cure the main parts in water, they seem to have enough mass to not warp.

the printer I am using is an Epax X1 straight out of the box, no mods.  This machine is a little more expensive than others but I have not done one thing to it.  With that being said, I did just receive two upgrade kits for it, one is the parallel light kit and the other is the 4K upgrade.  I hope to get both installed this week before I print the final cab and tender parts.  I was happy with the X1 as it was however the 4K mod is a mono screen and the print time will be cut down and the resolution increased enough that I may be able to print the cab with the builder plate on it.

the files are all my own.  I have been designing and testing this model for over a year.  I do not plan on selling files or parts at this time.

Jeff Kraker

Read My Blog
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MannsCreekRR Super User 157 posts
MannsCreekRR

engine detail added

I spent some time to add some more details to the shay engine.  For some reason the prototype had a strange (to me) arrangement of grease cups down on the crankcase.  From the builders photo I scaled to grease cups and printed both styles.  The cups are mounted with brass wire to make them more durable.  I could have printed the grease cups on the crankcase but the mounting pipe would have been really fragile and the brass wire makes them able to be bent back into place instead of just snapping off.  The smaller grease cups on the reverse rod and the valve chest are HO scale brass unions with the nut part filed round.

other parts added were the blowdown valve sets and the discharge header.  most Shays I have seen had the blowdown discharge header running down the front, but for some reason the MC had theirs routed to the back.  Again, I used brass rod for the control rod and discharge header.

this week I will blow off the dust and get it painted.  I have built a few brass shays and one of the hassles is that the model has to be build, tested and tuned, then disassembled, painted, reassembled, retest, retune, weathered, retest and retune.  With the resin shay I can paint and weather the parts as I go, assemble and test.  The tuning part is pretty much gone because all the "tune" in worked out in the design.  Also, by using black resin I only have to really paint he parts that are seen.  One issue with brass is that it is really hard to get into all areas, and then if the part is a moving part the paint will wear off and show the brass color.  One little detail that is hard to see is that I did not 3D print the piston rods, instead I just printed the crosshead and used a steel rod that I cut from a broken drill bit.  The drill rod has a nice color by nature and it will not wear away.

08-10(1).jpg 

Jeff Kraker

Read My Blog
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sunacres Frequent poster 700 posts
sunacres

Fabulous.

Just... fabulous. Thanks for sharing that last picture and comments.  

Jeff Allen

Jeff Allen

My MRH Blog Index
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