Large Scale Central

Experiments in 3d printing "Metal"

Thought I would start a new thread since we are now talking Metal. to be specific we are talking a Shape ways Process they call “Steel”

this is actually a stainless steel and nickel mix if I understand correctly. it is done by distributing a binder to a layer of metal powder,

followed by additional layers of metal powder and binder. the end result is sintered to bind the material together, resulting in shrinkage.

Below is my current cad file;

it shows two cross head locations because some folks have expressed an interest in an economy conversion kit that would use the existing driver

spacing. I am working towards doing the correct driver spacing .

the red features in the above drawing are the original C-19 locations

Some of you may have seen this project in other threads on Bachman C-19. So with interest in the project I bite the bullet and sent a couple of files in for metal printing.

the important part of this project was to find out what the results turned out to be dimensionally. I had up scaled my models by 1.03%, and this appears to be a good number.

the shape ways site is none to specific about the amount of shrinkage saying that for this material it could be up to 5%. why this material and not brass? simple economics my friends.

doing these with lost wax via Shape ways was more than twice the cost. and the added issue was that the main rod was to long to do in lost wax.

I looked at another vendor for the lost wax, but I would need to purchase 12 sets up front, at an unknown cost. while shrinkage is more stable at 2.5%.

if something was wrong I would have a bunch of scrap brass on my workbench.

from the above charts you can see what I wanted and what I got. the only issue is the length of the main rod

as it is 1/16" too long. and this length is important. I will adjust the file for the next print by artificially

adjusting this dimension, and leaving the hole out for later drilling. the Laird Cross head is good to go!

Disclaimer: the above results relate directly to the parts printed. your results may vary.


That material looks awesome. Great work!

Will you be making them available on Shapeways when you are done?


that will be the end result.

Jon, It has a little texture to it. I think they try to minimize this thru the polishing process. some of the detail is rounded over more than I would like.


I’ve said it elsewhere, but I’ll say it again. This is the future of modeling, where we will design / buy / borrow files and take them to our hobby shop for printing. Thanks for the glimpse into the future!

Well I promised an update earlier this week. I did receive the next batch of parts on Tuesday, and for the most part am happy with the results. on two parts holes were not cleaned out of the powder, and were sintered that way. the result was effectively no hole. talks with Shapeways on this issue have indicated they will potentially reprint these parts, but not yet confirmed. this material is beyond hard, and although I tried to drill out, this had limited success, I reached out to the manufacture of the powder material, and they indicated slow speed drilling with carbide drill bits. I have a few on order due to arrive later today, so possibly another update with pictures tomorrow.

Al P.

How is the strength of these parts? Are they maluable, or brittle or just plain solid?


they are not maliable at all, I have not tried to break them, but they have been dropped a couple of times.

They are a mix of stainless and bronze 60/40 I think. IMHO they are strong enough for hobby use.

if I knew what I know today I might have bypassed Shapeways and gone with the manufacture of the printer,

as they offer this service as well. price is a little higher but if dimensional stability is there then it is more than worth it.

company Name is EX one. material hardness after annealing is 93HRb it is supposed to be soft,

but the material propertys may dictate the type of cutters used.

Al… BTW if you were not aware of it… 315 has different main rods on each side. One was replaced and the other is still original… they have a different main shape and style of bearing…

Dave Taylor said:

Al… BTW if you were not aware of it… 315 has different main rods on each side. One was replaced and the other is still original… they have a different main shape and style of bearing…

Ah, but do we know the exact date and time the rod was replaced? Say I was modeling December 11, 1941; it might matter if I modeled morning or evening ( to count rivets or anything, but this stuff matters!

@Al and Jon… September 1945… Durango…

The Strap-stub main rod on the right side was replaced with a solid end rod…

Atta boy, Al! Very thorough work!

I’ve had small brass parts, and a few wheel hubs in SS, printed at Shapeways for hobby project; they have great detail. Last week I had a number of large (~8" long) parts printed for a project in China (for my day job), all in aluminum and for rough service in some machinery. I was informed a couple days ago that they’re working just fine, and are very strong.

Planning on doing a number of parts in brass now, because it’s more tappable than the SS. I don’t think I’d have much luck tapping #0-80 threads in printed stainless, even with the treads modeled in. But I’ll probably try, because their volume pricing is too good to pass up.

Carry on, sir! Your work is always fascinating to watch.



Took a look at Craftcloud, some of those materials I recognize as form 2 materials, others are from EX one, who is the manufacture of those metal materials/printers. I recognize other materials there from the high end printer I was first introduced to back in 2006. so basically they are providing a full spectrum of 3d print services. one thing I did note is they didn’t offer any shrinkage projections for these materials either, in fact there is little guidance on model size and makeup of thin walls for instance. So I think they will be trial by fire as well on the metal (steel) materials.

I will be tapping some of these this afternoon, will see how it goes. initial trial indicated it would not be a problem. I think once the outer skin is breached it may be a softer center. I only did a quick trial last night wit a .04 dia. carbide drill and it made chips from the start. these drill bits are a little pricey though.


Well it is too late now, at least for my model, as the parts received of the left and right main rod are good once I drill the hole for the wrist pin. I will look in the big book to see the differences this evening.


Al, yes please report on how the tapping goes, like what thread size, how deep and tap type / material.

I’ve ordered SS parts from SW a couple years ago, but recent description changes made me write SW a couple weeks ago to ask if their regular steel was stainless steel. They said no, their true SS is only added to your material list on request. So they switched it on for me, but I saw it was a lot more expensive then the material I had used. So are you using their “steel” or fancier SS? Did anything change other than material description?

Seems like 3D hubs is also much cheaper for (what that claim to be) SS parts.

Its now a 0-6-0 sort off!


Well the latest batch of parts arrived almost a week ago, but brought with it its own set of problems. you can see from the picture below

that holes that were supposed to be thru were plug solid. after a little searching I found that a carbide drill bit would do the job.


at this point I have only drilled out one, as I have decided that these parts are too much work post process, and have ordered up the

appropriate brass bar stock to machine these from solid. the economy version suffers from a worst fate as it would have needed blind holes.


looking at the fire mans side you can see that I made the guides too short, requiring new parts anyway.

the top guige if you look carfully is sort of banana shaped. this may be a reflection of how it was positioned for sintering process.


the engineers side, you can see ahead of the modified cross head support the alum adaptor plate I made to allow repositioning the support.


and finally the bottom view, showing the geared axle and the new location for the valve gear on the third axle.

there is machining to be done on the frame to clear the valve gear bits, but that will wait until the frame pieces are made and fitted.

the new main rods which I shorted by 1.5mm seam to do the trick (foreshortened for printing) I had left the wrist pin hole out of the rod for this build,

but will add back in for any future use, as I had to drill out with carbide drill as well. the intermediate rods came out great with

one small exception and that is the Bachmann bearings fit in one w/o issue, the second I had to grind out a little to get the bearings to fit

(we are talking thousands here), and they were a little long, but that is designed into the frame pieces adjustability,

the front rods will be fit as well once the frame is back together.

my synopsis of this process is that it can be useful as seen above, but does have some limitations,

that being small holes were not cleaned out prior to sintering, warping noticed on one part, and dimentional stability on longer parts like the side rods are an issue.

be prepared if you experiment with this technology , that you may need to make dimensional adjustment to your files to get the end result you desire.

while I considered getting a quote from the manufacture of the equipment used to produce these parts for the frame pieces, I think that machining them will be the best course $$$ wise.

and Cliff asked about tapping, well the original goal was to have the lower crosshead guides tapped 00-90, and will be in the machined versions.

I was able to get a tap part way thru using lots of lube and making small turns back and forth. the lower guides are about 1/8 thick and the tap got to the point

where it was just coming thru the other side. but did want to go any further. I probally dulled the hell out of the tap as well.

I had enough threads to get screws in w/o issue, but to do the second one would require a new carbide drill as the .04 (1mm) one decided to break on the second hole.


My feeling has been that the process is better suited to detail parts such as perhaps bells, compressors, number plates than to structural, precision machine parts, but it sounds like you are making it work.

Al, it’s looking great! Love the details of fasteners, oilers, etc.

And I’m glad you got as far as you did with 00 tap. Did you get some specially hard tap?

Your project reminded me of one that Richard Kapuaala did for a loco build a few years ago, on MLS. But all his pics are gone from his threads, that I can see. Anyway, similar issues.

Interesting how metal printing has changed a lot over a few years. Here’s an overview from 2010, kinda messy and laborious.

And here’s an example of how Markforged does it now:

Eric, I’ve only used the process for detail parts, but the results appear to be rugged enough for larger functional pieces, or are at least getting there quickly.

Looking forward to more of your progress Al, keep it up!


The tap I used is an old J I MORRIS tap in a set my father purchased in the 70’s maybe, so if I need to replace it was not an issue.


the cross head guides which were the simplest of parts turned out to be the biggest problems. at this point I have determined I have made a dimensional error

and will not be able to use these pieces, and will remake using stock brass shapes with a little milling. this was my original intent anyway,

I tried 3d printing them from the standpoint of making them available as part of a conversion package, but this will not work.

So if you would like to do a hands on with this material, I will mail you one of my failed parts, for your use. there are only a few pieces available so first come first served with a PM

(Stan I have you covered)

Ultimately if you can afford to have metal parts processed by one of the giants like Mark Forge, they have the technology. they seem to have the best on a lot of fronts.

I think you will get what you desire. in the hobby field IMHO there is a limit to the precision you can get.

Al P.

Folks, this can thru in an email this morning. while not directly related to trains it is a miniature model of an engine block.

this is the latest tech in 3d metal.