TT:120 - 16T Mineral Wagons

[J-Lewis]

I've been toying with the idea of 3D printing some wagons for TT 120.  I really wanted to get some 16T Mineral wagons.  So far no RTR examples are announced so as the best way to trigger a RTR release of anything is to scratchbuild one...

 

I've created a 16T body with a little extra length to fit the Hornby vent van chassis.  This is the first step, I intend to develop a version with chassis and NEM pockets next.

 

It's my first time 3D printing anything so I was curious to see how much detail I could retain at such a small scale, so this first design includes the handles on the end door as well as the fillets under the edge of the wagon.

EDIT: The 3D file is now available if you want to try it the 3D printing this wagon body.  STL file available free here: https://skfb.ly/oJtXP

 

Edited July 15, 2023 by J-Lewis
Adding link to 3D printing file

[Flying Pig]

Good plan.  Hopefully Peco are reading.

 

I notice that you have left out the top flaps above the side doors - are you going for a very early wagon or a later rebody?

[J-Lewis]

Its supposed to be a later version (I'm modelling early 70's).  I can easily make versions with the extra flaps and riveted versions if anyone wants them.  I will have the files available in Shapeways if everything goes according to plan.

 

 

Edited May 19, 2023 by J-Lewis
Adding pictures

[natterjack]

I doubt you will get 3D printed handle-holds so you have the choice to make them solid or mark the hole locations for detail add-ons- also in my experience around 0.2mm is the thinnest you can reliably get from good printing services (without warping etc)- no idea about Shapeways. Incidentally why use them as they are amongst the most expensive? Finding a better and cheaper producer and directing customers to them would be my approach. PM me if you want some UK based suggestions.

 

 

[D9020 Nimbus]

It's possible Peco might do this in the future, since they're planning to produce it RTR in N.

 

Wouldn't a 7-plank wagon — Hornby or the forthcoming Peco one — be a better basis for the chassis?

[J-Lewis]

7 plank might be a better fit.  To be honest I’d assumed the vent van and the planks used the same chassis.  Looking at the specs it turns out the planks are 4mm shorter.  I can easily adapt the design to fit a different chassis.

[HSB]

Apart from a batch built in the early 70s on redundant Palvan chassis' they should be 16' 6" long on a 9' wheelbase chassis. Somebody actually does various 3D printed versions of the mineral wagons although the chassis' aren't as accurately detailed as the Hornby ones.

[J-Lewis]

Once I’ve got this version to a good result I plan to build a correct scale version with a chassis to fit wheels from the 3mm society and nem sockets to fit the tillig couplers.

 

Biggest question I have at the moment is resolution, I’ve seen photos of 3D printed models with a lot of stepping, I’m hoping that the smoothest plastic will reduce that.  

[Ravenser]

1 hour ago, J-Lewis said:

Once I’ve got this version to a good result I plan to build a correct scale version with a chassis to fit wheels from the 3mm society and nem sockets to fit the tillig couplers.

 

Biggest question I have at the moment is resolution, I’ve seen photos of 3D printed models with a lot of stepping, I’m hoping that the smoothest plastic will reduce that.  

Do this as one of the 1976 Horwich rebuilds on Palvan chassis - for which no top flap is correct - and then go for the full on "standard" 16T wagon

[natterjack]

4 hours ago, J-Lewis said:

Biggest question I have at the moment is resolution, I’ve seen photos of 3D printed models with a lot of stepping, I’m hoping that the smoothest plastic will reduce that.  

3D services with newer equipment can do step free printing- but this sort of gear is presently a bit steep for domestic budgets (and perhaps a bit too smelly). It is also worth bearing in mind the option of resin casting from a surface finished 3D original which can be readily extended to a batch operation of say, ten at a time. Epoxy resin is both shrink and stink free.

[J-Lewis]

I’ve ordered test prints from a couple of different suppliers.  Looking forward to seeing how they turn out.

[Grovenor]

On 20/05/2023 at 17:38, J-Lewis said:

Once I’ve got this version to a good result I plan to build a correct scale version with a chassis to fit wheels from the 3mm society and nem sockets to fit the tillig couplers.

If its a scale version to 1:120 then you need wheels to 1:120, 3mm society wheels will be to big.

One hopes Hornby or Peco will sell wheels seperately in due course.

[cctransuk]

On 19/05/2023 at 10:03, J-Lewis said:

 

 

Please don't copy the livery of this preserved wagon - except in a VERY few (erroneous) instances, vacuum -fitted wagons did NOT have black backgrounds to their markings.

 

It amazes me that supposedly expert preservationists get these basic details wrong.It

 

CJI.

[J-Lewis]

Thanks for the info.  I've bought some Railtec decals and they come with and without boxes so I should have the correct ones.  First test print has arrived.  This is the shapeways 'smoothest detail plastic' version.  Looks pretty good, detail is much better than I expected.  Even the handles printed ok.  Some stepping in the sides but hopefully will smooth out once painted.

[HSB]

5 hours ago, Grovenor said:

If its a scale version to 1:120 then you need wheels to 1:120, 3mm society wheels will be to big.

One hopes Hornby or Peco will sell wheels seperately in due course.

The axles are also too long!

 

[J-Lewis]

 

Well hopefully suitable wheels will be available somewhere  :)   If not, I’m sure it won’t be long before someone makes them.

[J-Lewis]

I received a test print in grey resin today, this is very smooth, much smoother than the shapeways plastic version.  The sides are showing a little distortion in the resin version so I will thicken up the panels to reduce that.  I suspect the resin will be a lot more brittle too.
 

I’m definitely impressed with how much detail is retained in these.  My next steps:

 

1.  Adjust design to fit on a 7 Plank chassis which should also be closer to the correct length for a mineral wagon.

2.  Add the top flaps to the side doors.

 

 

 

 

[markw]

On 23/05/2023 at 21:52, J-Lewis said:

 

Well hopefully suitable wheels will be available somewhere  :)   If not, I’m sure it won’t be long before someone makes them.

Osborn's Models have these,

https://www.osbornsmodels.com/ocww-altt100-1120-metal-wheels-3-hole-disc-4-axles-55797-p.asp

[Flying Pig]

2 hours ago, J-Lewis said:

Adjust design to fit on a 7 Plank chassis which should also be closer to the correct length for a mineral wagon.

 

Is the Hornby 7 plank actually scale length?  Photos I've seen suggest it is stretched to fit the standard 10' chassis, but it's hard to be sure.

[J-Lewis]

Hornby TT120 7-plank seems correct length (or close enough).  It’s 45mm over the buffer plates which works out at a scale 17ft?  The wagon has 10ft wheelbase instead of 9ft, but its certainly closer than the vent van chassis I was originally going to use.

 

 

[Flying Pig]

50 minutes ago, J-Lewis said:

Hornby TT120 7-plank seems correct length (or close enough).  It’s 45mm over the buffer plates which works out at a scale 17ft?  The wagon has 10ft wheelbase instead of 9ft, but its certainly closer than the vent van chassis I was originally going to use.

 

 

 

Thanks for measuring the model.  In fact, 44.73mm scales out very close to 17' 6" in 1:120, so this does appear to be the standard 10' underframe.

[J-Lewis]

Actually I was wrong.  The 7plank chassis is exactly the same length as the vent van.  The only difference is that the plank wagon has the ‘doorstops’  moulded in under the doors.  Wheelbase appears to be the same for both of them. I thought the vans were longer?

 

I will keep the current designed length for these bodies and design a new chassis from scratch for my scale length version.  Unless someone announces a more suitable RTR chassis in the meantime.

 

 

[Moxy]

7 minutes ago, J-Lewis said:

Actually I was wrong.  The 7plank chassis is exactly the same length as the vent van.  The only difference is that the plank wagon has the ‘doorstops’  moulded in under the doors.  Wheelbase appears to be the same for both of them. I thought the vans were longer?

 

I will keep the current designed length for these bodies and design a new chassis from scratch for my scale length version.  Unless someone announces a more suitable RTR chassis in the meantime.

 

 

 

It depends. RCH specifications did include both open wagons and vans that were 17'6". Early wagons of this length had 9' wheelbase, later ones 10' wheelbase. (This is a very general overview, there were different lengths/wheelbases for specialist traffic.)

 

The 16T mineral you have designed should be 16'6" long with a 9' wheelbase.  I think making it fit an existing chassis is a reasonable compromise, in the circumstances.  As others have said earlier in this thread, 00 manufacturers have made similar compromises in the past, and most people were happy to accept those models.

[J-Lewis]

Body goes together ok.  Floor needs to be a little thicker to allow for the screws to fix it into position (the Hornby screws are too short and these M1*4 screws poke through the floor).

 

Thicker floor and slightly thicker sides should help to reduce resin warping as well, currently 0.6mm on the sides, so adding 0.2mm or so should make a difference, hopefully without making it look too chunky.

 

 

[Dava]

I’ll just add that Simon Dawson who sells his work via Rue d’Etropal and his Recreation 21 shop on Shapeways converted a selection of his 3D print designs for TT120. These include variations of the 16 ton mineral wagon and separate 9ft underframes/ chassis which can be bought in 4’s. Link here. 
https://www.rue-d-etropal.com/3D-printing/3d_printed_sg-trains3.htm

 

I haven’t ordered any as I haven’t committed to TT120 yet and a Shapeways order has to be big enough to justify the on-costs, and wheels weren’t readily available when I looked. 
 

Maridunian's Models By Mike Roch also does some 3D print wagons, and 10ft wb chassis, via Shapeways but not the 16 tonner

Dava