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Board Game Accessories - Prototype Model Trains - Custom Cutting and Engraving

Prototype Model Trains

Buildings

Train Electronics

Free-mo Fitter Rail Tool

Free-mo Track Height Tool

Leg Pockets

Optical Detector Mount

Rail Joint Bars

Rolling Stock Weight Ruler

Switch Machine Mount

Throttle Holders

Throttle Jack Faceplate

Throttle Jack Router Template

Tie Strips

Train Car Box

Track Laying Guides

Track Spacing Tool

Tray, Stacking Organizer

Zephyr Mounting Shelf

Custom Cutting


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Information, Tips, Tricks and FAQ

About Prawn Designs


Signal Mount Removable

Who has not bumped and damaged a valuable signal when cleaning track or working on your layout? I do Free-mo modules, with all the moving and adjusting it is just that much easier to hit and brake a signal. My friends and I thought about how to make a removable signal mount that was small and easy to use. Prawn Designs in conjunction with Big Ditch Designs has come up with this solution.

A few of the goals were:

I recommend wood glue or white glue. I would not use cyanoacrylate adhesive (CA), it does not work well with wood.

Click on any image to open a larger version in a new tab.

Signal on Module / Layout

This is what the mounted signal looks like.

The top of the signal base has not been sceniced yet.

Signal NOT included.

Signal Mount Top View

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This is everything and how it looks assembled. The laser cut parts are mounted under the module or layout.

The laser cut parts are the prototype, the production version might very slightly.

Signal NOT included.

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Signal on a PCB Stick

The signal is mounted on a PCB Stick that goes down into the Laser Cut mount.

Signal NOT included.

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Signal Mount Main Base

The Laser cut mount that is mounted under the module or layout.

The laser cut parts are the prototype, the production version might very slightly.

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Bottom of the Laser Cut Mount

The heart of the mount is the Bottom PC board that is on the bottom of the laser cut parts. There is a pair of spring contacts in the center of the PCB that the stick slides down into to make the connects from the stick to the module or layout. This is a prototype PCB on the bottom, the production board is a little different.

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Bottom PC Board Layout

The Bottom PCB board is laid out in two halves, the left side (outlined in red) for head A and the right side (outlined in green) for head B. Depending on what connector you want to use to connect your signal driver to the Signal Mount you would use either J1 and J2 or J3 and J4.

Across the top of the board are solder pads for your current limiting resistors for your signal. Resisters are not included, the value will depend on the exact signal you are using. Note, there are a set of pads for surface mounted resisters if that is what you like to use.

Solder all the components onto the same side as the spring clip.

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Assembly Instructions

Click on the button below to expand the step by step assembly instruction for the PD & BDD Signal Mount.

The parts of the PCB Stick

The PCB Stick has three parts. The stick, a double row header, and a disc that the signal mounts to.

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The PCB Stick Assembled

This is what the assembles PCB Stick looks like.

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Top of the PCB Stick

The top of the PCB Stick is a 3/4" round disc that the signal is mounted to. We recommend some kind of glue like 5 minute epoxy. There are 8 solder pads for 4 wire from each head. The fine wires are kept between the round disc and the bottom of the signal, protected from getting snagged.

NOTE: This disc us upside down, ERROR

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Connection Options

There are three connector options for connecting your signal driver to the Signal Mount. First there is a Modular 4P4C Jack (J3 and J4) for plug and play ease using a Big Ditch Designs Signal Driver. We included a 0.10" (2.54mm) spaced set of solder pads to take a pin header or a screw terminal. A fourth option would be to solder wires right to the board on the pads.

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PCB Stick Assembly Step 1

Place the double row header on the top of the PCB Stick. The long pins onto the stick is preferred but not required. Solder both sides.

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PCB Stick Solder Jig

We make a soldering jig to help hold the PCB stick while soldering the parts onto it. The double row header it stays in the stick and it not bad. But the next step is to solder the PCB disc onto the top of the stick. Placing the stick in the jig makes it easy to keep the PCB disc square to the stick. If the round is not square to the disc, your signal will lean.

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PCB Disc Placement

One side of the PCB Disc has one square on it, the other side has two squares on it. The side with the one squares goes up. See the image below. Place the stick in the jig, place the PCB Disc on top of it. Be sure the disc is level and solder in place.

You can use the jig to hold the assembled stick while you solder the signal wires onto the stick. Then glue the signal onto the stick, watching to be sure the signal is vertical.

NOTE: This disc is upside down.

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Laser Cut Base Parts

On the top are the laser cut rings, the bottom are the base pieces. There is also a small dowel included.

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Main Bass Assembly

Gather the 5 main base pieces.

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Do not use any glue yet, place the two smaller spacer piece into one of the sides.

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Place the second side onto the assembly.

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Place the side assembly onto the bottom.

It is very important that you do not get any glue in the center slot formed by the sides and spacers. I do not put any glue on these pieces. I put a small amount on the bottom before I place the sides assembly onto it.

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I use a q-tip to mop glue around the base.

Again it is very important to not get any glue in the center slot.

Let the assembly dry. 

Base Rings

There are 10 round rings and one square ring. By changing the order of the rings the mount can be adjusted in 1/8" (really closer to 0.12") steps to accommodate different thickness of module tops (bench work). The system is adjustable between 5/8" and 1 1/4". When measuring your bench work thickness remember to include the thickness of your scenery material where the signal will be mounted.

Note: Two of the rings are a little fragile and sometimes break, so I include some spares rings, not shown in the image.

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Ring Assembly

You can do a dry fit without glue to check the height of the stack to your bench work, the fit on the dowel is very snug. Be careful, you can break the rings putting them together and taking them apart.

In this example I am assembling a mount for module top (bench work, sub-roadbed) that is 5/8" thick. This measurement is the distance from the of the module top to where you want the base of the signal to sit including scenery material.

Take the small dowel and cut two pieces about 2" long. Stack the discs, in order, onto the two dowels placing a small amount of glue between each disc.

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After the first set of discs put the rectangle on. This is the mounting plate, it will be screwed to the bottom of you sub-roadbed.

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In order place the rest of the rings onto the dowels.

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Put the Rings on the Base

This stack is now placed onto the base. I use a q-tip to mop glue onto the sides of the base and slip the rings down on. Be sure to seat the rings all the way down onto the base. The first of the top rings keys down onto the base, look down into the top to ensure it is seated all the way down.

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In this example I made the shortest mounting base possible with only the 5 required rings on the top. You can see that the 5 required rings make a mount for 5/8" thick sub-roadbed. This measurement includes any scenery (dirt, ballast, etc.) that will be under the signal base.

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When the glue dries use a knife to trim the dowels flush.

Thicker Bench work / Taller Mount

To make a mount that is taller, move one or more of the rings from the bottom to the top of the rectangle piece.

The one on the left is setup for 5/8" the one on the right is setup for 1".

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Mounting the Bottom PCB

You should have soldered in your resisters and connectors (Modular 4P4C, pin header, or a screw terminal) you choose to use. The picture below does not have the connectors or resisters installed on the Bottom PCB

The part you will need are:

  • The Bottom PCB (with resisters and connectors soldered on)
  • (4) #4-40 1/2" Machine Screws
  • (4) #4 washers
  • (8) #4-40 nuts
  • Signal Mount Everything

    Install Machine Screws

    Install the 4 machine screws from the side with the components and put a nut on the back of each screw. Tighten the nuts down snug.

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    Mount PCB on Base Assembly

    Place the Bottom PCB onto the Main Base assembly and place one washer and one nut on each or the mounting machine screws, do not tighten these yet, leave them loose.

    Note, there will be some play this will allow the Bottom PCB to move around a little.

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    Align and Tighten the Bottom PCB

    Place a PCB Stick into the Main Base assembly from the top. Use it to align the Bottom BCB, then tighten the nuts. You should be able to remove and insert the PCB Stick with just a little force. Loosen, realign, and tighten the nuts if needed.

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    Connecting Your Signal

    At this point you should have:

    • The Main Base assembled for your thickness of bench work where you will be installing the signal.
    • Your resisters installed on the Bottom PCB
    • Your choice of connectors installed on the Bottom PCB
    • The Bottom PCB aligned and installed on the Main Base
    • The PCB Stick, double row header, and PDB Disc soldered together.

    Time to connect your signal to the PCB Disc on the PCB Stick. Solder the signal wires from your signal head to the corresponding solder pads on the PDB Disc.

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    Test and Glue Signal to PCB Stick

    You should test your signal head before gluing your signal to the PCB Disc.

    This system is designed to have the flat side of the PCB Stick facing the track, see the image below.

    After you have tested your signal, tuck the extra wire up into the base and glue the signal base onto the PCB Disc.

    Signal NOT included.

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    Mount the Main Base Assembly

    The System requires a 3/4" hole in your bench work. Bring the Assembly up from the bottom and screw it into place. Ensure that the PCB stick is aligned correctly.  

    Signal Mount Top View

    Title 2

    Place your signal on the PCB stick into the mount and press down gently on the PDB Disc to set it into the base. To remove the signal, press up in the bottom of the PCB stick to lift the signal slightly out the layout. Then lift the Signal out by the PCB Disc.

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    Ordering

    To place an order send an email to orders@prawndesigns.com . Include a list of what you want to order (Part Number and Description) and your shipping address. We will get back to you with an estimate of when we will have your order is ready to ship and shipping costs.

    Some items are available in the Prawn Designs Etsy Store.

    Please read the Laser Cutting and Engraving FAQ page for details on laser cutting and engraving side effects.

    

    Part Number Title and Description Price Image

    PD-21082

    Signal Mount Kit by Prawn Designs and Big Ditch Designs

    One Singnal Mount Kit by Prawn Designs and Big Ditch Designs. Supports two heads each with a common and 3 control wires.

    $24 Signal Mount Everything

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