Hi Missy,

They look good. Have you printed them in FUD or another material? I always wanted to print some wheels but didn't think FUD was strong enough and the other materials were not fine enough. Depending on how you get on I'll have to rethink that....

Also did you turn your own tyres?

3D-printed wheels are an ingenious idea - Bill Bedford's producing much the same thing for P4, with one or two teething issues along the way - I'll hopefully be able to post up some photos of the Q1 wheelsets I'm trying out.

What you don't want to end up with is such a loose-fitting wheel centre that the axle slips right through.

Hello Guys

Hi Missy,

They look good. Have you printed them in FUD or another material? I always wanted to print some wheels but didn't think FUD was strong enough and the other materials were not fine enough. Depending on how you get on I'll have to rethink that....

Yes they were printed in FUD. Alan Cox said in a post somewhere a while ago that the material was similar to whitemetal and I think if you treat it the same you wont go far wrong. So far it seems to stay in place with no movement of the center on the shaft or rim/tyre. Of course time will tell if this works, especially once I get the thing running.

Also did you turn your own tyres?

No, these are from the 2mm Association. They are the 'standard' ones they use for the existing wheels available through the association shop.

3D-printed wheels are an ingenious idea - Bill Bedford's producing much the same thing for P4, with one or two teething issues along the way - I'll hopefully be able to post up some photos of the Q1 wheelsets I'm trying out.

 

What you don't want to end up with is such a loose-fitting wheel centre that the axle slips right through.

I really think there is potential with these, even in 2mm Scale. As you saw at Railex they are my first attempt so the next ones should be a little better.

The wheel-to-rim and wheel-to-axle are both interference fits (hence having to press them together) so technically there shouldnt be a problem with anything being losse fitting.

M

.....The wheel-to-rim and wheel-to-axle are both interference fits (hence having to press them together) so technically there shouldnt be a problem with anything being loose fitting.

You haven't seen Bill's wheels.

You haven't seen Bill's wheels.

No I havent. Is there something I should know?

No I havent. Is there something I should know?

The set I have are very loose. If it wasn't for the keyed axles (they are there to set the quartering automatically), the things would pass right through the centres with very little effort.

The set I have are very loose. If it wasn't for the keyed axles (they are there to set the quartering automatically), the things would pass right through the centres with very little effort.

That sounds like a design error to me, something wasnt measured or drawn correctly.

I was fortunate in having some great drawings of the rims so I could engineer the interference fit in, 0.1mm for both wheel-axle and wheel-rim which seems to have done the job so far. The accuracy of the printing seems to be good enough for that not to be an issue. Of course 'standard parts' i.e. parts made to a drawing (with tolerances) does help lots.

M

That sounds like a design error to me, something wasnt measured or drawn correctly.

 

I was fortunate in having some great drawings of the rims so I could engineer the interference fit in, 0.1mm for both wheel-axle and wheel-rim which seems to have done the job so far. The accuracy of the printing seems to be good enough for that not to be an issue. Of course 'standard parts' i.e. parts made to a drawing (with tolerances) does help lots.

 

M

It sounds like a design error to me too. In theory the printing process is accurate enough to ensure interference fits should work as designed. I tried laser cutting some wheel centers a little while back (never did make tyres for them though) and a 0.1mm interference fit was fine for the axles... The nice thing about 3D printing is that if you make a mistake its a case of modifying the design and re-printing - only the cost of the original prints is lost and not the cost of any tooling.

Hello again

They look good. As well as the Q1 wheels there the spam cans and ther H spoke ones for GW 850 class and some LNWR types. Let alone the need for the Crankpins being either between or in line with the spokes.

Don

If this works then there is the possibility of doing the less common types of wheels. It does mean of course that the conventional way of building 2mmSA chassis wont work as the axle isnt split though. Its more useful for modifying RTR engines from Farish and Dapol.

ps Point rodding info sent by Email

Thanks Don (and Geoff) I havent looked at it yet but I will take a look later today.

A really excellent example of the potential 3D printing has in our hobby. Very nicely done! It looks as though the layering you sometimes seeon these prints is minimal too. It does really open up the possibility of quick and simpler wheel swaps for N Gauge steam.

Tom.

Thanks Tom. The finish on the wheels you see above is more the result of some over enthusiastic cleaning by myself with a wire brush. They really only needed a good scrub with a toothbrush or similar really. You learn by your mistakes! I am quite excitied about what would be possible if they do work, as you say it does open up many possibilities. A good example is that I have in the making some 6mm driving wheels, ideal for shunters and small engines which havent been available through the 2mmSA before.

One thing I am curious about though, is will the centres be subjected to any stresses from expanding & contracting rims under exhibition conditions, where they might be exposed to a wide range of temperatures in a shorter period than usual? Is the FUD material strong enough to cope with this over a long period of time?

Tom.

You are right Tom. It is early days with these and time will tell if they work or not. From what I can see when working with the stuff I cannot see any reason why it shouldnt work so far, unless of course I have missed something obvious. The next step once I fix the coupling rods in place is to run it as much as possible to test them out.

M

Hi Mark.

I have been considering changing the wheel to suit a square or maybe even a 'D' shaped axle. Maybe I should try it on the next batch of samples?

Yes, soldering could be fun. I was relying on the speed that it takes to solder the retaining washers on to not harm the wheels. Ironically the holes for the crankpins should be a 0.05mm interference fit but I didnt try it out on these but opting instead to drill them to fit the crankpins from the back. I like your suggestion though, the only thing that worries me a bit is how easy they would be to quarter (if the square/D axles dont work out).

Things to think about though for sure, thank you.

M

Brilliant, as an N gauger the world of finescale can seem a bit daunting, but seeing clever things happen using technologies I have a bit of an understanding of is encouraging. Thanks for showing the process step by step!

Hello Will.

Brilliant, as an N gauger the world of finescale can seem a bit daunting, but seeing clever things happen using technologies I have a bit of an understanding of is encouraging. Thanks for showing the process step by step!

Im glad you found it useful. One of the big drivers (excuse the pun!) behind this is to make it easier for people to convert RTR stuff to 2mm finescale. There are wheels for diesels and hopefully in the future there will be the same for steam...

M

Hi Don.

Dont forget the wheel center is plastic, therefore non-conducting so the half axle design isnt needed. There is no reason why you cant do that but you dont have to.

M

You could also print the centres with half axles on them or half axles with a 1.6mm outer and 0.8mm central hole for a metal rod to hold it together.

Pressing them just needs a block with a hole in it for the stub to dangle in.

Heat is lilkely to be a problem - FUD goes a bit soft about 70-80C and in boiling water you can reshape it permanently. Good for drilling and tweaking, bad for wheels.

FUD btw isn't entirely like white metal - it doesn't deform so easily so will resist a lot of small stresses far better and stay the same shape. On higher stresses it just shatters.

It's certainly far better for buffers than white metal for example.

Alan

Thank you for the comments Alan.

I could be wrong but I thought the main reason for the half axles was to maintain the split chassis design, therefore the center needs to be electrically conductive. As FUD isnt then to me it wasnt worth messing around with half axles but instead use the same methods as Farish and Dapol and rely on wipers. Its why I was thinking about these as replacements.

That is a low melting point, I guess thats inherent in the manufacture. I am struggling to see how an engine would ever reach temperatures like that though unless there is something seriously wrong with it. I might be wrong but the only time one of my engines ever got that hot it had already fried the motor. Considering the only real path for the heat to conduct from the chassis is through the axles (and through radiation) I just cannot see how the wheels would get that hot.

Thanks for the tip about the material quality though, certinaly from what I have seen with assembling the wheels they were much more robust than I first expected. Im going to have a go at some buffers soon, I am guessing for the heads you stick to the 0.3mm wall thickness?

M

Makes sense re the half axles. On the heat subject I was meaning with respect to soldering not running.

I've stuck to about 0.4mm (0.3mm on the edges) with the various Gresley buffers I did.

Thanks Alan

On the heat subject I was meaning with respect to soldering not running.

Ah ok, I have soldered the crank pins on the pannier tank and it takes a fraction of a second to solder each one. I havent noticed any damage. As mark metioned previously there is always the option of holding the coupling rods by instering a pin through the coupling rod and into the wheel cutting off any excess.

M

Thanks for the reply Don.

That is certianly a thought on the wire. The dilemma I have is where these wheels would be useful and I honestly think they could work for replacement wheels for Farish and Dapol RTR stuff, then use something else for replacement chassis using 2mmSA split chassis design. I am sure in time though that it will be possible to print some kind of conductive plastic which then would make the choice a little easier.

Of course there is still a big IF hanging over everything as this is just one of my ideas and Im sure there will be better solutions from other people..

M

Re shorting out the wheels, could you etch a backing piece to the profile of the spokes and somehow get that to make electrical contact with both the tire and the axle? Some form of alignment could be printed onto the wheel center to ensure all lines up as it should...

Alternatively, etch the entire wheel and solder up in layers - something I was thinking about a few years back but never got pass the armchair stage!

Thanks for the reply Don.

 

That is certianly a thought on the wire. The dilemma I have is where these wheels would be useful and I honestly think they could work for replacement wheels for Farish and Dapol RTR stuff, then use something else for replacement chassis using 2mmSA split chassis design. I am sure in time though that it will be possible to print some kind of conductive plastic which then would make the choice a little easier.

 

Of course there is still a big IF hanging over everything as this is just one of my ideas and Im sure there will be better solutions from other people..

 

M

You can already print metal, or if the price makes your eyes water use the FUD as a master to cast your own in whitemetal.

I like the idea, especially for extended axles, which you will be requiring for another current project. I got as far as making an adaptable cad model that will draw any size wheel with any number of spokes, including adjustable crank throw and then did nothing with it. Credit is due for having the determination to have taken things further!