Weird idea - 3d printed steam drivers

[kiwi_al]

I must get more sleep!! So I got thinking (never good) after seeing mike lawyers posts and talking with Adam (drasskouasshat) about steam drivers that would be needed for various steam prototypes (warning I model ATSF). If you were to design and make a steam driver, would you make a 3D resin printed disc with spokes and add a disc with spokes and / or a disc with holes in it like a bokpok that fits into a metal rim (tread and flange) or if you could, would you have the whole thing 3D printed in metal?
I'm leaning towards 3D printing the whole thing in metal.
I'm not saying I'll do this cause I'm crap at 3D design, but I am curious about the possibility.

[Lemosteam]

Unless you found an investment caster that has exquisite casting capabilities, this could be folly.  Not trying to quench the idea, just my experiences here.  HO and larger scales maybe.  Even if you machined them after casting, treads, rod pins, eccentric hole shape and orientation, etc., it could be an expensive proposition.

This is what printing in metal looks like, N scale tender floor. No sharp corners, limits on feature dimensions no smaller than 0.8mm, minimal details, min hole sizes, etc.:



This is what brass investment castings look like using printed burnouts, permanently coupled N Scale Kinematic coupler:

[peteski]

While there are some exceptions, great majority of N scale steam models have drivers will metal tire and plastic spokes insert.  I suppose 3D printed centers might be doable for that.

[Lemosteam]

While there are some exceptions, great majority of N scale steam models have drivers will metal tire and plastic spokes insert.  I suppose 3D printed centers might be doable for that.

Tooling up the metal part for that is not cheap either.  Pressing a shaft into a resin print is impractical as well as the material is not soft like Delrin or styrene.  I understood what the OP wrote.  I was primarily commenting on the second part about an all-metal driver.

[Simon D.]

This guy in the UK sells wheel rims in various sizes on Ebay: https://www.ebay.co.uk/itm/115292946314?hash=item1ad7febf8a:g:n6cAAOSwLJ5iLhHf


Not sure how useful they might be.  9mm is just over 56 scale inches according to DKS's scale dimension converter.

[Lemosteam]

This guy in the UK sells wheel rims in various sizes on Ebay: https://www.ebay.co.uk/itm/115292946314?hash=item1ad7febf8a:g:n6cAAOSwLJ5iLhHf


Not sure how useful they might be.  9mm is just over 56 scale inches according to DKS's scale dimension converter.

Very cool, thanks!

[garethashenden]

I have made two locomotives with 3d printed wheel centers, both in 4mm/ft (1:76). They work well, I used tires from commercial drivers. The 2mm Association has recently switched from cast brass centers to 3d printed ones, although they use turned steel tires.

[peteski]

I have made two locomotives with 3d printed wheel centers, both in 4mm/ft (1:76). They work well, I used tires from commercial drivers. The 2mm Association has recently switched from cast brass centers to 3d printed ones, although they use turned steel tires.

Good to know that this  method works.  As for the steel tires, is it plain bare steel prone to oxidizing (rusting), or is it nickel plated or stainless steel?

[garethashenden]

It’s mild steel but rust isn’t really a problem. It is in theory, but in practice it’s not a problem. If rust does show up it’s easy to remove with some micron paper. A smoother surface also helps prevent rust.

[peteski]

It’s mild steel but rust isn’t really a problem. It is in theory, but in practice it’s not a problem. If rust does show up it’s easy to remove with some micron paper. A smoother surface also helps prevent rust.

That's good to know because in my experience older Arnold locos used steel tires, but they were also plated with some non rusting metal - I suspect nickel.  When I turned down the flanges, the exposed steel at the edge of the flange did eventually develop some rust.  Since the rust was not on any areas that contact the rail, it was not a problem.  I guess abrasive wheel cleaning will take care of any surface rust.

[kiwi_al]

Thanks for the responses, it's quite interesting to see different peoples views. There's a lot of food for thought in these posts.
My main idea is that I shouldn't need tooling if the 3D metal printing is good enough. Next month I'll send a company I deal with a 3D design - a very simple wheel blank and see what I get back regarding accuracy and quality and whether they can produce the hole sizes I need (They will be small). If the parts require expensive tooling, then the technology isn't ready for what I need.
By the way I'm not using Shapeways as their fidelity is poor. I quite like the idea of 3D printing a disc and having the metal tire pressed over it. I'll also be following up on the provided links, they look promising.

[garethashenden]

My wheels don’t have the tires pressed on, the resin is too brittle for that. They are a close fit and held by loctite.

[JeffB]

My wheels don’t have the tires pressed on, the resin is too brittle for that. They are a close fit and held by loctite.

I epoxy the tires on, but use high quality industrial grade CA to hold the center/tire assembly on the axle...

Jeff

[Sokramiketes]

Yes, N scale needs more steam drivers because not every driver was spoked!  I'd like to see some modern drivers to fit Bachmann driver centers.