Switch Machine Linkages Used by me on my O Scale layout

These methods allow you to mount the Tortoise switch machine under the sub roadbed at the edge of the layout where adjustments of the throw are much easier than under the layout.  Method 1 is for shorter distances and Method 2 uses a longer flexible set of sheath and rod that can be obtained rather long and can have some curves in it to reach a turnout that can’t be reached directly.

List of Materials:

.039” or smaller piano of music wire.  If I want a spring switch I would use say .025 wire instead

1/8” Brass Rod or Tube e.g. K & S.  I use tubes mainly.

5/32” Brass Tube for the Rod to rotate in.

3/16-1/4” x .032 - .064” Brass strip.  I have used both thicknesses. Don’t go any lighter then .032

2-56 threaded at one end push rod.  Available in 12 and 30 inch lengths

2-56 threaded clevis e.g. Tower Hobby LXK077 (12)

Tower Hobby LXFU90 Sullivan Flex Gold-N-Rod 36”.   Longer is available I believe. 2 sets include clevis and stud.

Ring Connector none insulated type for #6 studs.  This is the smallest you can get.  The hole in the ring is suitable for the Tortoise Phillips Head screw.

Directions:

Cut the brass strip about 1-1/2” long.  Drill one end with a 1/8” drill.  Drill several additional holes the size of the pin in the clevis which is about 1/16 or less. Cut a piece or 1/8” rod or tube about 3 inches long.  Cut a piece of 5/16 tubing about a ½ inch longer.  Clean up the cuts so the 1/8 slides smoothly in the 5/16 tubing.  Then as close to the end of the 1/8 drill a hole with a #58 drill or small if you are using a lighter piano wire.  Then apply some paste to the 1/8 bottom end and to the hole in the brass strip.  Insert the 1/8 into the strip.  Insert a short piece of piano wire in the hole.  Then align the tube parallel or at 90 degrees to the strip (depending on the position the turnout in relation to the switch machine) and holding 1/8 as straight up and down as possible apply solder to the parts.  One helpful thing is to drill a 1/8 hole about a 1/8 deep into a block of wood so the 1/8 piece can go through the strip and beyond a bit. The piano wire helps with the alignment. 

Drill a 5/16 inch hole through the roadbed and sub roadbed between two ties from the throw rod on the turnout.  Insert the 5/16 tube to the top is flush with the top of the ties.  Mount the switch machine under the layout.  Determine how long the push rod or sheath and rod needs to be as close as possible and attach the Ring connector to the none threaded end of the rod with paste and solder.  Now thread a clevis about half way onto the threaded end of the push rod or the stud if using method 2.  Attach the clevis one of the holes in the brass strip.  I generally use the hole the farthest from the tube, but you may have to change the hole depending on the amount of pressure required to properly throw the turnout.

Now from under the layout you can insert the 1/8 up into the 5/16 tube.  While holding it in that position you should be able to insert a piece of piano wire with a 90 degree bend into the 1/8 tube and the other end the throw rod of the turnout.  Some turnouts a have to enlarge that hold slightly to fit the piano wire I am using. 

Check to see how close you are with the ring connector to the hole in the switch machine throw.  Also is you center the switch machine throw first and center the turnout points, you can screw the push rod in or out to fine adjust the throw.  Insert the screw and tighten carefully but not tight.  Apply power to the switch machine and make additional adjustments.  For 90 degree situations you can also add Bell Cranks e.g. LXDCT6.  I have done this in a couple of situations.  In one example I wanted all the switch machines (4) in one location.  So to reach one turnout I set the switch machine 90 degrees, ran a push rod parallel to the edge of the benchwork to a bell crank and then to the turnout.  Works great.

When using the flexible method 2, secure the sheath several places e.g. drill a hole through a girder or use “U” shaped electrical staples.  I have the electrical staple gun for this.

Tomorrow I will post some photos of typical arrangements and uses.

For more information email me at James@thebeckhams.us