Sharp Stewart Small Passenger 2-4-0 locomotive parts and assembly

[Rob R]

Timber,

 

Thank you for posting these especially the wheel. I have a possible need of a 5' 7"plain driving wheel for an outside framed loco so I had a little play.

A quick cut and paste:-

Whether the resin I am using is up to the job is another issue entirely.

Rob

Apologies, probably should have put this on one of the other threads.

R

Edited December 16, 2021 by Rob R
Insert extra photo, Apologies.

[Timber]

Here is the 10 spoke leading wheel.  This has to be printed with a diameter of 14.96mm to fit the society 3'7" tyres.   The same wheel is used for the tender.

 

https://drive.google.com/file/d/1w7JGbftnplCjYqzrkPpZTrBXQqFOy4Nq/view?usp=sharing

 

[Rob R]

I like the nice thin rim on that one. 

Would it be possible to thin down the rim on the driving wheel?

Earlier locos tended to have a more spidery look. A thinner rim should print ok and once it is glued into the tyre it should be plenty strong enough.

Thank you for posting your work on here.

Rob

[Timber]

Rob - no problem - I can do the rim thickness to what ever people want.   In fact I have made some wheels for another member with a thinner rim.   My only caution is that (as we all know) a plastic wheel is more flexible than a metal wheel.   I spent some time trying to optimise the wheel design so that it had minimum flex without becoming a solid piece of plastic.  This involved thickening the rim as it does make a difference even with a big dollop of glue.

 

But maybe a resin print will be more sturdy.   I will make the changes and post.  I would be interested in feedback.

 

But if anyone is setting out on an S Scale journey and this is their first loco then I would recommend this wheel.   Once you have built your track and have smooth operation then that may be the point to introduce finer wheels.

 

 

 

[Timber]

The leading wheels may be tricky to print.   To help I have a strip that you could send to Shapeways.   It is configured to have the maximum number of wheels for their smooth plastic table.   With Shapeways the cost is determined by the material plus handling time and cleaning time.   A strip of 18 is not that much more expensive than a single wheel.

 

https://drive.google.com/file/d/1Ntv7DYFdM-v7ASjqD8bnRPorNQfBp-IA/view?usp=sharing

 

 

[Rob R]

Thank You Timber.

 

The first thing to do on the resin wheel front is to print some and work out the shrinkage and adjust the scaling accordingly.

 

There are some quite useful engineering resins out there, about four times the price of the water washable stuff I am using at the moment but only pushes the price up to about 20p a wheel ( for the 5' 7").

 

I will post any progress on that in the Wheel Thread.

 

Rob

[apl31]

Rob,

Going back to the Timbers dome STL files you amended.  Did you make the changes within your CAD software or an external software?

I have tried to convert the STLs in Freecad. I managed to convert the leading wheel to a mesh then a solid. The chimney converted to mesh but not a solid - it wasn't a shell? I tried to convert boiler assembly but it was taking forever trying to convert to mesh.

I did download something called meshlab but its too complex, I don't understand the problem never mind the required solution.

 

[Timber]

Importing STLs is not always as simple as you would wish, something I find strange given the idea behind STL is that it is supposed to be portable.  In Fusion it is imported as a mesh and you then have to convert to a Solid.   But I have never really understood why it does not get imported as a Body or a Component.  Tinkercad is very good at importing STLs so i suspect that Rob did not hit the problem.  Let me post a link in the CAD section of RMWeb and see if anyone has any ideas.

Edited December 18, 2021 by Timber

[Rob R]

The dome was hollowed out with Tinkercad, imported in as an stl, once it was in you can do what you want with it as per normal tinkercad limitations and then exported out again.

BUT.

There is a limit to the import size - 25Mb, ok for small bits but the Albion boiler assembly was too big at 29Mb. I have not yet tried the boiler on it's own but as all that is needed for a trial print is a hole in the top of the smokebox I might try the hole/hollowing functions in the slicer instead. It will have to wait until I'm off work next (monday) and join the 3d cad queue ( gnr open wagon, wheels etc).

Have fun and keep safe

Rob

Ps. I think that Solid Edge that Jim is using may be able to deal with imported stls more like TC than Freecad or Fusion. Jim, if you see this what to you think?

R

Edited December 18, 2021 by Rob R
Addendum

[flubrush]

1 hour ago, Rob R said:

Ps. I think that Solid Edge that Jim is using may be able to deal with imported stls more like TC than Freecad or Fusion. Jim, if you see this what to you think?

R

 

Rob,

 

I haven't tried that yet being still at the learning stage with the software.  But I'll have a go and see what happens. :-)   Now on V9 of the mineral. :-)

 

Jim.

[Timber]

As advised in other thread I have updated the chimney and full body posts with STEP files as well as STL.  @apl31  be interesting to hear if you can open these.

[apl31]

This question started here before moving onto the wider 3D thread for discussion, so I thought I would record here the result of importing STEP files into Freecad.

STEP files import directly into Freecad. They can be easily rescaled and reoriented if necessary.

The STEP file can be split into constituent parts/bodies as shown in screen shot.

The boiler is Timbers original boiler with a spigot added for new smoke box, the nameplate was also removed. The resulting part was saveable as a STL file. The chimney is made from Timbers base with a new barrel on top. 

So  Fusion STEP files can be editable in Freecad. Thanks Timber.

[Timber]

Someone has requested a copy of the Tender etch artwork.   Here is the PDF that can be checked before ordering.   The cost for this etch is £25 not including postage.

 

The etch supports a variety of different designs.  Early tenders had a rear tool box, some Tenders had a curved front step others a straight front step.   This etch will support these variations. 

 

34603-3 07.04.21

 

 

Sharp Stewart 4 Wheel Tender 2021 integrated etch 06042021.pdf

Edited January 13, 2022 by Timber