3D Printed Train Wheels

[legoman666]

https://www.shapeway...ego-train-wheel

I uploaded this model (not of my design) and ordered a few in Stainless steel so I can pull up power from the track. They look great. Someone else ordered 4 of them. I only got 2 to test but just placed an order for 6 more. Working on some of the bigger Steam wheels in SketchUp so I can upload and get some in SS too.

I use phosphor bronze wire bent in to a spiral to scrape the back the wheel to pick up power. Works great and is cheap. I'll post a link when I finish the bigger wheels. I make no money from uploading these.

[garethjellis]

Just looked at the pictures zoomed in,I wonder what the substrate is they used along with the metal. I wonder what the wear and conductivity will be. I am going to attenpt to mill these out of Aluminium

Edited January 29, 2015 by garethjellis

[legoman666]

You can look at the higher res originals if you get rid of the h at the end of the jpg name. On imgur, h creates a "huge" thumbnail.

I've watched videos of 3d metal printers. They use some sort of metal sand that gets melted by a laser 1 layer at a time and built from the bottom up. I assume these were made using the same tech.

Edited January 29, 2015 by legoman666

[mrseven]

"Someone else ordered 4 of them....", I#m the one who orded these wheels.. Shipping wil be Feb 10. Meanwhile I'm veery interested in seeing your solutions.

[jtlan]

Just looked at the pictures zoomed in,I wonder what the substrate is they used along with the metal. I wonder what the wear and conductivity will be. I am going to attenpt to mill these out of Aluminium

I've watched videos of 3d metal printers. They use some sort of metal sand that gets melted by a laser 1 layer at a time and built from the bottom up. I assume these were made using the same tech.

Most metal printers use the Selective Laser Sintering technique. Small metal particles are slightly (but not fully) melted by a laser, causing them to stick together -- this is responsible for the grainy texture seen on the parts. Another layer of particles is added and the process repeated. The flange of the above wheels shows some ridges -- these are the individual layers of metal. In general, the parts will be a bit porous and somewhat weaker than equivalent parts machined out of solid pieces of the same metal -- but for this application that's probably irrelevant. I'd be more concerned about the ridges on the flanges clicking against the rails (and possibly wearing the metal coating on the rails).

@legoman666, how is the grip on the cross axles? The manufacturing tolerances for Lego parts is quite high, and I'm curious how well the metal parts matched them.

Edited January 29, 2015 by jtlan

[coaster]

Most metal printers use the Selective Laser Sintering technique. Small metal particles are slightly (but not fully) melted by a laser, causing them to stick together -- this is responsible for the grainy texture seen on the parts. Another layer of particles is added and the process repeated. The flange of the above wheels shows some ridges -- these are the individual layers of metal. In general, the parts will be a bit porous and somewhat weaker than equivalent parts machined out of solid pieces of the same metal -- but for this application that's probably irrelevant. I'd be more concerned about the ridges on the flanges clicking against the rails (and possibly wearing the metal coating on the rails).

@legoman666, how is the grip on the cross axles? The manufacturing tolerances for Lego parts is quite high, and I'm curious how well the metal parts matched them.

jtlan nails it, but just to add, typical tolerances on the metal SLS machines are within .08mm, and many offer even tighter ±.05mm (at double the price, mind you). I believe Lego's typical tolerance is ±.01mm, which is about as tight as you can get with most machining operations. I would guess the printed parts are adequate for this, but I'll parrot the concern about wearing the plating off the rails.

EDIT: You need the spokes on that wheel too!

Edited January 29, 2015 by coaster

[legoman666]

The axles fit in the holes (obviously) but are a very tight fit. I didn't want spokes because I've never seen a spoked wheel on a diesel in my life.

Why would these wear the track down any faster than the regular 9v motor?

[jtlan]

The axles fit in the holes (obviously) but are a very tight fit. I didn't want spokes because I've never seen a spoked wheel on a diesel in my life.

Why would these wear the track down any faster than the regular 9v motor?

Better too tight than too loose, I guess? I'll note that Big Ben Bricks flanged wheels fit pretty tightly as well.

The metal parts of the 9V motor's wheels are sprung, which means that weight on the motor is carried by the tires, which are rubber. The ridges on the flange of the printed wheels may also have a filing/scraping effect around curves.

[coaster]

It'll probably be fine, but my concern with the wheels wearing the rail plating was because of the printed surface finish. I suppose as long as they're just rolling and you're not driving with them, you should be fine. As for the spokes, I was just thinking for consistency with the plastic Lego version.

[legoman666]

I understand your concern. My interest in this is to both drive with and pick up power at the same time. Otherwise I wouldn't need the Technic axle hole. My other steel wheels I use don't seem to be wearing down the track, but they're smooth.

[jtlan]

I understand your concern. My interest in this is to both drive with and pick up power at the same time. Otherwise I wouldn't need the Technic axle hole. My other steel wheels I use don't seem to be wearing down the track, but they're smooth.

??? Is there room for a tire? I'd be worried about lack of traction from metal-on-metal...

[Aaron]

Thank you for making these! I build American diesels, so I've been wanting non-spoked wheels with Technic axle holes for a long time. The metal is especially appealing, so I'll probably buy a bunch eventually.

I do kind of wish for a version where the center of the wheel is larger in diameter compared to the flange, more to scale with real train wheels, but still retaining the 3 stud diameter. My trains are heavy enough not to derail. Any chance this could be done? I'd buy a ton of them for all of my rolling stock.

[legoman666]

Thank you for making these! I build American diesels, so I've been wanting non-spoked wheels with Technic axle holes for a long time. The metal is especially appealing, so I'll probably buy a bunch eventually.

I do kind of wish for a version where the center of the wheel is larger in diameter compared to the flange, more to scale with real train wheels, but still retaining the 3 stud diameter. My trains are heavy enough not to derail. Any chance this could be done? I'd buy a ton of them for all of my rolling stock.

It's certainly possible, but it'll still derail through switches. I have some of Alain's custom wheels that cause issues in switches if they're not perfectly spaced. My locomotive's are heavy too. I can make them for you if you're still interested.

??? Is there room for a tire? I'd be worried about lack of traction from metal-on-metal...

These are for pulling power up from the track, a rubber traction band would kind of defeat the purpose ;)

[jtlan]

These are for pulling power up from the track, a rubber traction band would kind of defeat the purpose ;)

??? But you said:

My interest in this is to both drive with and pick up power at the same time. Otherwise I wouldn't need the Technic axle hole.

Are other wheels being powered?

[legoman666]

??? But you said:

Are other wheels being powered?

Nope, my CSX has 4 powered axles and 2 dummy axles with all with steel wheels. It can pull my 16' consist no problem.

[Aaron]

I'm definitely interested. I have ME Models R104 curves on the way, and I'm probably going to design and print my own R208 curves and switches eventually, so there should be no risk of derailment.

My scale is 1:38, and I have coaches with 36" diameter wheels and diesels with 40" diameter wheels, which translates into 3 studs in diameter (24mm) and 26.73mm respectively. Even just a standard 3 stud diameter wheel with more realistically scaled flanges would probably work for everything. Not sure if there would be much of a noticeable difference on the Alcos if the wheels had a difference of ~2.73mm.

[Exa]

I see there is also a track cross 90. Looks great.

http://www.shapeways.com/product/HQRM2KSYX/lego-train-track-cross-90-degree

[legoman666]

I see there is also a track cross 90. Looks great.

http://www.shapeways.com/product/HQRM2KSYX/lego-train-track-cross-90-degree

Indeed. I uploaded that too, but it is not my design. I've ordered 1 copy of it. Works okay although I bought it in white so it kind of sticks out. It's tough to put Lego tile on the sleepers. The studs are ever so slightly too big.

Putting the finishing touches on my steam wheel, model is complete but shapeways is giving me issues with it when I upload it.

Edited February 1, 2015 by legoman666

[coaster]

Putting the finishing touches on my steam wheel, model is complete but shapeways is giving me issues with it when I upload it.

What format do you have it in? I might be able to clean it up for you.

[legoman666]

What format do you have it in? I might be able to clean it up for you.

.stl , Shapeways keeps filling in the pin hole for the driving rod. Not sure why, it's just a simple cylinder. I'm also worried about the resolution of the circles that Sketchup makes.

[jtlan]

.stl , Shapeways keeps filling in the pin hole for the driving rod. Not sure why, it's just a simple cylinder. I'm also worried about the resolution of the circles that Sketchup makes.

From what I've heard from other peoples' experiences, Sketchup is a pretty poor program for making printable .stl files; the shapes often wind up full of holes. Try using something like Meshlab to clean them up?

[codefox421]

From what I've heard from other peoples' experiences, Sketchup is a pretty poor program for making printable .stl files; the shapes often wind up full of holes. Try using something like Meshlab to clean them up?

I made this using SketchUp, and it printed okay: https://www.shapeways.com/product/RMEMYNGSK/?key=ea32833352d8e409e982b2c6b1df137f

I did have to be really careful when creating it though. SketchUp does magic things in the background, and sometimes they mess things up really good.

[coaster]

Email me your .stl file. I've never used SketchUp, but I have Inventor, so I should be able to open and repair your model. I can also test it on our 3D printer's software, see if I get the same issues.

[legoman666]

I tried Microsoft's little netfabb tool, it fixed one of the errors but left two. I tried using Meshlab to convert from .dae to .stl, and the resulting model was identical, errors and all. https://www.dropbox.com/s/2x2opw4l9pguxg1/wheel2_fixed%20%282%29.stl?dl=0 Here's the file netfabb created. I might have to start over from scratch, pretty low res curves, although I might order one in plastic just to check fitting.

[coaster]

Apparently, "round" is not in SketchUp's vocabulary:

I assume that upper hole is supposed to be a technic pin hole? I don't have time at the moment, but give me a day or 2, and I'll redraw this for you.