3D Printed Thompson B1

[choochooenthusiast]

This is the start of my 3D printed B1 thread. Lots of head scratching and corrections to get Martin Evans Springbok design starting to look more prototypical. Of course, the benefit of making it out of plastic is that you won't have steam running through it, so you can go crazy with the necessary changes. 

[choochooenthusiast]

I can't upload images for some reason, it says the limit on images in this forum is reached. Weird.

[racinjason]

You will need to use an external hosting site there are a few to choose from, in the general chat section there is a pinned post with help and hints from the other members. Please share your work and experiences.
Regards Jason.

[coniston]

Jan 21, 2021 3:46:57 GMT choochooenthusiast said:

This is the start of my 3D printed B1 thread. Lots of head scratching and corrections to get Martin Evans Springbok design starting to look more prototypical. Of course, the benefit of making it out of plastic is that you won't have steam running through it, so you can go crazy with the necessary changes. 

Can't wait to see progress on that one, I have a steam B1 as well as an active interest in 3D printing.

Chris D

[choochooenthusiast]

Read quite a few comments in the general chat, I've joined photobucket so we'll see if this works...

Here are the mainframes and bogie frames, mainframes yet to have that paper wrapping peeled off. These were laser cut in 3mm acrylic, the closest I could get to 0.125", I've adjusted the size of the stretchers in CAD so the correct spacing is still retained on the outside edge of frames.

app.photobucket.com/u/ChooChooEnthusiast/a/a23f8d84-2c1a-4095-bb71-b12d9e4cd2a2/p/238845b9-518a-4e40-91f7-2055d2d0909e


Connor

[choochooenthusiast]

Thankyou Jason for your suggestion, hopefully the hosting site works.

Here's a photo of some of the stretchers in CAD. Mounting holes are designed into the components for metal 'heat set inserts' to be inserted, this provides stronger threads.

app.photobucket.com/u/ChooChooEnthusiast/a/bb6ea085-9f22-455b-884d-bdc1feee0ae2/p/ae7e8479-5b20-4aa4-8352-8716e87d5bc4

Connor

[Neale]

Unfortunately, Photobucket insists that I sign up in order to see the images. Is there an "embed link" option so the images appear in the post itself, rather than having to click?

[choochooenthusiast]

Hmmmmm, I've made both albums public and redone the link, hopefully it works now. Unfortunately this is the new norm because of the forum image limit.

[uuu]

I just thought I'd try embedding one of your images here - it seems to work.



This is using the "Share" feature in Photobucket, then the "Insert image" here.

Wilf

[choochooenthusiast]

Jan 22, 2021 12:19:16 GMT uuu said:

This is using the "Share" feature in Photobucket, then the "Insert image" here.

Wilf




Doesn't seem to be working, are you using the free Photobucket like I am?

[uuu]

Jan 22, 2021 12:28:36 GMT choochooenthusiast said:

Jan 22, 2021 12:19:16 GMT uuu said:

This is using the "Share" feature in Photobucket, then the "Insert image" here.

Wilf




Doesn't seem to be working, are you using the free Photobucket like I am?

Yes - i'm not a photobucket user myself - I just clicked on your links to view the images - which didn't work initially, until you'd tweaked them - this is my attempt at the other image:




Wilf

[uuu]

Note I'm not copying the URL from the browser address bar - I'm clicking the "Share" button in Photobucket.

Wilf

[choochooenthusiast]

I've got it to work, finally!

On with the build!

Connor

[choochooenthusiast]

Just a quick one today, a friend of mine has printed some parts while I wait for my printer to arrive. Here is a quick close up of the horn blocks.

They are really crisp, though the photo isn't... sorry.



I've decided to bolt them to the frames with countersunk screws instead of riveting them, that's why the holes are there. They won't be easily visible once the loco has been assembled but they still look alright.


Connor 

[uuu]

Looking good. Are you aiming to be able to run the model on air?

Wilf

[barlowworks]

Jan 24, 2021 3:36:33 GMT choochooenthusiast said:

Just a quick one today, a friend of mine has printed some parts while I wait for my printer to arrive. Here is a quick close up of the horn blocks.

They are really crisp, though the photo isn't... sorry.



I've decided to bolt them to the frames with countersunk screws instead of riveting them, that's why the holes are there. They won't be easily visible once the loco has been assembled but they still look alright.


Connor


Could you use roundhead slot less screws instead of countersink. I think the real thing would be riveted. 


Mike

[choochooenthusiast]

Thanks Wilf.

I'm not sure about the prototype, but the model was meant to be rivetted.
Thanks for your suggestion Mike, I was going to countersink the holes in the frames so the screws are clear of the driving wheels. 

Connor

[92220]

The horns would definitely have been riveted on fullsize, not bolted. Bolted would run the risk of loosening in service due to vibration. They would almost certainly have been hot riveted too, like boiler rivets were, as when the rivets cooled, the tension in the rivets, holding the joint tight, would be much greater than a nut and bolt could provide.

Bob.

[choochooenthusiast]

Thanks for your insight Bob. I did notice Prince of Wales’ horns are bolted, I wonder why they did that instead of hot riveting them.

Connor

[kipford]

the tension in the rivets, holding the joint tight, would be much greater than a nut and bolt could provide.

Bob
I do not think this is quite right. You can make a bolted joint withstand shear and tension loads far higher than any riveted joint, hot or cold set. The difference in material properties alone between a rivet and a high tensile bolt will determine that. They would have hot riveted probably for speed and cost.
Dave