Printing DIY-wagons, how do you carry out bearings for wheels

[Slanjonok]

Dear friends of 3D printing in 2mm,

I'm currently trying to adapt an OO wagon for N gauge. Unfortunately, the axles don't move smoothly enough. I used plastic axles from PECO on my railway crane. That wasn't great either, but smooth enough. This time I have to install metal axles because they fit best geometrically. I also checked everything geometrically and made several test prints, so everything should be OK in this respect.

I would have expected that metal axles should even work better with the resin axle bearings, but the opposite is the case. They only rotate with remarkable resistance. The resin is the same as for the rail crane - SUNLU standard transparent blue.

Does somebody have any idea? How do you make your axle bearings?
And yes, brass sleeves would be nicest, but they don't fit geometrically into this wagon.

Thank you in advance for your hints!
Kind regards, Sascha

[garethashenden]

What is the axle length? I suspect there are probably differences between the plastic and metal axles, as well as the OO wagons that have been reduced to N. That's the first thing I would check. If the metal axles are slightly longer they will have much more resistance. 

[Slanjonok]

4 hours ago, garethashenden said:

What is the axle length? I suspect there are probably differences between the plastic and metal axles, as well as the OO wagons that have been reduced to N. That's the first thing I would check. If the metal axles are slightly longer they will have much more resistance. 

Thanks for asking. Yes the axle geometry is different, as is the geometry of the wagon. I changed the wheels by that reason as themetal ones fit better to the this wagon (D5.2x14.0mm). But in respect to the geometry at the bearing and how the axle sits in everything is similar. I checked this twice in CAD-program. I adjusted already the bearings, compared to the OO-wagon, means I widened it by somewhat 0.5mm.

Might be the metal wheels are harder and therefore are able to create more abrasion, then the plastic ones - just thinking.

[The Fatadder]

For my prints I include a recess to accept a commercially available etched w iron.  Makes life a lot easier (and tbh I find it looks better as well)

[Slanjonok]

3 hours ago, The Fatadder said:

For my prints I include a recess to accept a commercially available etched w iron.  Makes life a lot easier (and tbh I find it looks better as well)

Thanks for reply. Do you have a picture and a source for better understanding? Would be great!

[njee20]

Just try and move the axle boxes out/thin them slightly. I find my printed wagons roll well. They are very sensitive; 0.5mm can be the difference between binding axles and dropping out! I found trying to accommodate top hats in N was more disruptive. YMMV.

[Slanjonok]

11 hours ago, njee20 said:

Just try and move the axle boxes out/thin them slightly. I find my printed wagons roll well. They are very sensitive; 0.5mm can be the difference between binding axles and dropping out! I found trying to accommodate top hats in N was more disruptive. YMMV.

Thanks for reply! What resin does you use?

[njee20]

It depends, but usually Sunlu ABS-Like or Siraya Fast. For bogies I mix in some Siraya Tenacious. I tend not to use that for bodies, because you get slightly 'softer' definition, so it's a balance for two axle wagons. The ladders need tidying up on this under cruel magnification of the camera, but this was Sunlu ABS-Like, and uses metal axles, either Intermountain or Exact Rail.

 

[Slanjonok]

@njee20 Many thanks, I will creat a test print with different bearings to test it out.

[Jeff Smith]

Peco 0-16.5 coach and wagon kits use metal pin-point axles and nylon top-hat bearings - they run very smoothly - perhaps you could print in nylon, at least the axle boxes.

[12A Models]

Printing the "w-irons" in resin is asking for trouble as you put immense strain on them just by trying to insert and remove the wheelsets. I print my chassis in PLA filament as a kind of plain generic unit and then dress them with resin printed details. For bearings I use Markits brass shouldered pinpoint bearings. I model in OO but assume similar are avilable for N?

[number6]

Is this a model of one of those EE Engine carriers for DEMUs? 

[12A Models]

22 hours ago, number6 said:

Is this a model of one of those EE Engine carriers for DEMUs? 

It is, yes. Good spot!

[KeithHC]

1 hour ago, 12A Models said:

It is, yes. Good spot!

Is it available.

 

Keith

[12A Models]

19 hours ago, KeithHC said:

Is it available.

 

Keith

Hi Keith
Will be soon. Building up the first batch of OO and N versions and will release all at the same time.
The OO comes with chassis, bearings and wheels, the N version will be offered with and without a PECO 15' chassis kit.
You can find me on Ebay at 12a_models and also contactable through the Milepost128Modelling website.