Don't use whitemetal. It has been tried and bends if the loco is not left upright. You can use FUD to cast in brass, if you can find a caster to do it for you. I suspect he will insist that you fill one of his flasks before he'll agree to do it.

Hi Guys.

These are hopefully going to be part of a much larger picture. I am actually using 3D printing for what it was designed for! If the 3D printed wheels prove to be a viable route for making oddball wheels then that is an added bonus.

There isnt really much point in casting the wheels in brass as this is the route the 2mmSA already has taken and the main problem is that lost wax (or 3D print) casting just isnt accurate enough and therefore requires post casting machining to bring them into acceptable tolerances. I would be very surprised if whitemetal would fair much better.

M

I would be very surprised if whitemetal would fair much better.

The previous iteration of 2mmSA driving wheels had, iirc, whitemetal centres. I only mentioned printing metal because of a comment about making the wheel conductive.

Looks great - I'm hoping to follow in your footsteps soon.

Off the top of my head (i.e. I have no idea if it would work) - you could paint the inside face of the wheel with conductive silver paint to provide an electrical connection from rim to axle. One of these may do the trick:

http://www.ebay.co.uk/sch/i.html?_nkw=conductive+spray+paint

http://uk.farnell.com/jsp/displayProduct.jsp?sku=725614&CMP=KNC-GUK-FUK-GEN-LISTINGS&gross_price=true

http://www.maplin.co.uk/electrically-conductive-silver-paint-36275

Wear may be an issue though if the wheel rubs on the frame.

Thanks Rabs.

Good idea with the conductive paint although my only experience with it wasnt very successful so I am unsure if it will work or not. My idea was to use wipers to make electrical connection through the wheels. I mean if it works for Farish and Dapol then it must be ok to use!

M

P.S. Im looking forward to seeing some stuff from you soon then...

I'm sceptical about this technology for wheels if the design axle bore tolerances are in the order of 0.1mm or greater. FUD is quite brittle though, so an attempt at an interference fit might result in too much stress and possible breakage. Maybe one of the more resilient plastics would be better than FUD?

Bore tolerances of greater than 0.1mm could play havoc with bore-to-crankpin distances.

I'm even more sceptical about the ability of this technology to produce self-quartering solutions. Plug in a 0.1mm tolerance on a keyway design or D-shape aperture and the possible rotational error of wheel on axle is large.

Hello

I'm sceptical about this technology for wheels if the design axle bore tolerances are in the order of 0.1mm or greater. FUD is quite brittle though, so an attempt at an interference fit might result in too much stress and possible breakage. Maybe one of the more resilient plastics would be better than FUD?

I am sceptical at the moment too hence the testing, its all too easy to dismiss something without trying it. FUD is quite brittle but it seems to be happy so far with a 0.1mm interference fit, especially as there is quite a bit of material surrounding the bore to support the fit. Unfortunately due to the size of the wheels components it limits quite drastically the materials I can use. I chose FUD quite simply because it was easy to order and quite cheap. I know there are better options out there but for me at this stage its doing what I wanted it to do.

Bore tolerances of greater than 0.1mm could play havoc with bore-to-crankpin distances.

They could but I doubt it. You would have to get quite a serious alignment error to have problems. The crankpin-to-coupling rod usually has much more than 0.1mm play anyway for one example.

I'm even more sceptical about the ability of this technology to produce self-quartering solutions. Plug in a 0.1mm tolerance on a keyway design or D-shape aperture and the possible rotational error of wheel on axle is large.

Hmmmm, I am going to disagree with that. I think you are concentrating too much on extremes of tolerances. With a bit of thought and experiment I can see no reason why it cannot be done...

M

I think you are concentrating too much on extremes of tolerances.

I'll plead totally guilty on that!

I'm sceptical about this technology for wheels if the design axle bore tolerances are in the order of 0.1mm or greater. FUD is quite brittle though, so an attempt at an interference fit might result in too much stress and possible breakage.

Interesting -- The original meaning of FUD was Fear, Uncertainty and Doubt, and you do it so well.............