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Print a Midland wooden signal


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This summer I am experimenting with 3D printing 4 mm scale signals for my LMS layout. TheSignalEngineer posted a great prototype picture of a Midland twin signal here and I decided without any hasitation to use this for my second project. There are four positions on my layout, where I need a signal like this, so it makes really sense to build a reproduceble 3D model. Like most of you I used mini servos. One of them is a SG90 type from EBAY, the other is a similiar type from the Digikejis Servo Starter set. I can't recomend the Digikejis - it's very noisy and rough geared - but it works so far.

The model consits of four moulds: The signal post, the arms, the servo mounting and a connection part (blue) that is for planting the signal. The control wires are 0,8 mm brass, but will look better in 0,6 mm or even less. I was not shure about printing this L-shaped hinges from resin, but they work well, although they hve to be thicker than brass. The two lanterns have 3mm openings in the bottom to fit there either a warm-white LED or a conventional lamp. I wanted to model the back-blinders aswell, so there is a non prototype connection to the arms... well, a compromise. I am controling the servos by an Arduino UNO. This 10 GBP controller can operate up to 12 servos, so using these SG90 servos (1,8 GBP) it's really a budget-friendly way to signal your layout. So let's take the model to paint shop...

 

See it in motion on YouTube

Thanks for all your information! Below I uploaded the STL files for anyone who is interested:

20210807_190515.jpg

20210807_191217.jpg

MT_root.stl MT_ServoMount.stl MT_signalBody.stl MT_Arm.stl MT_L_connector.stl

Midland_Twin.jpg

Edited by PatriotClass
Forgot a picture
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16 hours ago, Harlequin said:

This looks very good!

Have you thickened parts over the prototype dimensions to ensure they will print?

What printer did you use?

 

I used a three year old ELEGOO mars printer. So the print took 7 hours. I thickened just the hand rails and the safety ring at the top end of the ladder. These parts are printed in a diameter of 0,8 mm. I tried 0,6, on my Claughton handrails, but this won't bring satisfying results. To get here more prototype look, I suggest to knip off the resin handrail and replace it by brass. The arms have double the thickness of the prototype to give more stability, but I think, here it's possible to go thinner.

Edited by PatriotClass
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The blinders look a bit odd, they are usually fixed via the spindle that the arm pivots on, not via a strap around the edge of the lamp....

 

The rest is pretty good!

 

Andy G

Edited by uax6
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5 hours ago, uax6 said:

The blinders look a bit odd, they are usually fixed via the spindle that the arm pivots on, not via a strap around the edge of the lamp....

 

The rest is pretty good!

 

Andy G

They are fixed to the arm but the strap fits between the post and the lamp

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5 hours ago, uax6 said:

The blinders look a bit odd, they are usually fixed via the spindle that the arm pivots on, not via a strap around the edge of the lamp....

 

The rest is pretty good!

 

Andy G

They are fixed to the arm but the strap fits between the post and the lamp

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13 hours ago, uax6 said:

The blinders look a bit odd,

You're right! It's not a good compromise, indeed. 

 

8 hours ago, Paul Cram said:

They are fixed to the arm but the strap fits between the post and the lamp

That's possible to do so in the model, but I fear that the attatchment of the lamp may become to weak, when I give space for the strap. But I did it the lazy way: I applied a drop of super glue to fix the arm and the blinder to the shaft. When the glue has set, I removed the strap and, here it is! So I will keep the strap just as an assembly aid to fix arm and blinder exactly.

20210810_144828.jpg

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If you make the pin that holds the arm to the post a loose fit in the post, but tight on the arm and the blinder, then it will be possible to get the blinder to move with the arm properly.

 

Looks better already mind!

 

Andy G

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35 minutes ago, uax6 said:

If you make the pin that holds the arm to the post a loose fit in the post, but tight on the arm and the blinder, then it will be possible to get the blinder to move with the arm properly.

That's what I did and it works fine.

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Just catching the sun for drying. Here I made another one inspired by Mr Warburton's book. I wanted to try printing a lattice post and mount two arms on one post, The M2 screws at the arms are provisoric. The whole signal is one mould, exept the mechanics and arms and reaches up to 16.5 centimeters. I am just wondering if I should put in the arms colour filters or use a duo-LED that can display red and green by changing it's polarity.

 

If anyone is interested in the STL files, feel free to write a message.

LMS Lattice uq.jpg

Edited by PatriotClass
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