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1/72 Maritime Lift-Span Bridge

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2 hours ago, Hajo L. said:

Your very first model? Never did something similar before? I don´t believe you...! ;)


I think you maybe questioning my skills set. 


I have to admit, I am always surprised about it myself, yet see many others far advanced than my own. It will always be like that for everybody.


My background: Drawing, sketching, drafting, industrial design, diesel mecahnic, fitter-welder, Instrument fitter, electronics technician, and custom designed instrument maker for experimentations. Then I had a break from all that for twenty years until this project was requested from me.

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Thank you @Hajo L., and @Slartibartfast for such high compliments.

To be honest, I feel I don't deserve it, but the One that guides me; where the inspiration comes from.


It was at this stage of the project when I received an email from a museum colleage showing a faint picture of the bridge swing gates.

These gates were replaced with boom gates in 1995.

Finding photographs clearly showing what the swing gates looked like has been unproductive until now.




I used whatever I could find to make the gate assembly. Wire, tubing, washers, tin plate, fly screen, and couplings from electrical terminal strip.

Servo motors were too large to have installed directly under the road surface, so they had to be placed under the display table.

That is, the gate axles (#8 fencing wire) went between gate and servo.








The gate axles were able to be placed in such a position that they will became hidden from view by the console operator (museum visitor).

Edited by Tecko
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Dang! I've been watching this all along, and it's truly excellent work. It just keeps getting better and better.


You're quite modest!

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5 minutes ago, Silenoz said:

looking good... a bit weird that they don't close the bicycle lane off

Yes I know, and that there is no railing on the other side.

They may have closed the footpath, but I have no evidence or heresay to tell me differently.

Since 1995, a boom gate, at either end gets lowered across the road. Where the boom gate is, a swing gate closes off the footpath. And, there are no gaps in the railings.

Today, another set of gates, at the towers, close off the footpath again.

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Designing a circuit for this brand of servo mechanism.

Showing the two different signals for a 90+ degree shift in the servo arm.



Designed and built a printed circuit board for the four servos that control the gates.

The two blue trim-pots per circuit is for tuning in the servo arm to exactly where the open and closed positions are for each gate.



Made wooden brackets to keep both axles and servos at the correct distance for a linkage arm between the two.



Microswitches are positioned over each gate axle arm.

These enable the control panel lamps, and other circuits, when the gates are either open or closed.


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Designing the motor controllers for both the lift-span and the boat pulley systems.

Working out how to reduce the speed of the span lift motor.



Calculating the amount of motor axel drift after power is switched off.

This needs to be compensated for if the span is to dock on the bridge with minimum negative cable tension.



Designing the printed circuit board (PCB) for the two motor controllers (on one board).

Making the PCB.





Well, that's enough electronics for awhile. 

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There is a boat that traverses under the bridge in a straight line.

To eliminate the appearance of a normal boat reversing under the bridge, an abnormal boat is required. A boat with two front (bow) sections. To do this, I bought two identical wooden boat kits, so I could build a boat to those requirements.




I cut in half (broadest point) of the deck, and from that line I cut the keels and cabin walls. Then joined the bow portions together.

The planks were too stiff to just glue onto the bulkheads. A planking iron (heat-bending) was too expensive, but discovered a DIY method on the Internet by just using a teacandle and a tin can. This worked very efficiently and was able to bend the planks to suit the hull curvature.




Then I used the cabin ceiling as the horizon and marked on the bulkheads where I wanted the waterline to be. Planked the waterline. Then planked in between.




Used a hacksaw blade to cut away the bottom half of the boat. Then on a sheet of sandpaper, in a circular fashion, sanded the base level and smooth.




I really enjoyed building my first model boat. I can now understand why some modellers enjoy building them.

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  • 1 month later...

No response for over a month. Obviously nobody is interested in knowing how this diorama turns out. Pity I wasted so much time posting on this forum.

They were right, nothing much happens here for ship modellers.


To those that did respond, I say thank you :thumbsup:

But I shall not return here again. It's too clique.




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Sorry if you think so. You do your build to please yourself and enjoy it - if you share many others (including myself) will enjoy it myself. But when writing these lines, I use my sparse spare-time after a 12 hour work-shift, and simply want to get through all the interesting forum posts and also start my own modelling session.




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I have been enjoying your posts immensely. My dad is a big railroad modeler so I appreciate your skills and love watching your progress.


 I don't have enough time to reply to every post I enjoy, only certain ones, and usually so it is easier stay up to date with the e-mail alerts. Other threads I will quietly follow as a lurker when I find updates weeks, or months later. 


 Don't take a lack of responses personally. I have had many topics see hundreds of views but no responses.



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There is a thread over on BritModeller as well (until people stop responding to it I suppose).




This also happened on another Forum as well when people were just looking and not posting any responces.

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