I am in the process of finishing the fourth of five levels on the second spline helix.  It takes me about a week to add the section, install the cork roadbed and track and do the soldering required for the feeders as well as soldering the track sections.  This could probably be done faster if I was in a hurry or if I did not have chores around the house. 

I thought that a few pictures of how I add each helix section would be of interest so here they are.  The first picture shows the next section of spline helix ready to be lifted into place.  Either I got stronger or I've learned how to do this alone, but I am able to lift the section and put it in place and/or remove it by myself.  When building the first helix, I always needed help.  It may be the number of threaded rods in the first one caused some issues since I have cut the number in half on the second one. Each turn or section of the spline helix is not heavy at all but it is somewhat awkward to handle.

 

The second picture shows how the cuts are marked so the sections can be joined.  After marking the top and bottom cuts, the section is taken outside to be cut since I am trying to minimize the amount of dust in the train building.

The third picture shows the section after the cross cuts and the biscuit joint cuts have been made. I make the biscuit cuts for a #20 biscuit.  I try to use a #20, however, sometimes I have to use a #10 biscuit if the joint is too tight.

 

The fourth picture shows the joint has been made on a temporary basis while I mark the location of the screw eyes.  A rubber band can be used to ensure that your marking is exactly where the threaded rods passes vertically on the side of the spline or you can just use a calibrated eyeball (which is what I use most of the time).  Note, I had mentioned that because our local hardware store had burned to the ground, I had bought a lot of screw eyes from ebay.  The new screw eyes are a little longer and the wire diameter is bigger, however, they still work fine.

The fifth picture shows the installation of the cork roadbed and the trick that I learned during the building of the first helix.  Note that all of the screw eyes have been installed.  You can also see that the last part of the upper section has been left in a high position.  This allows me to work on the track on the lower section more easily.  When that work is done, then the upper section is adjusted to its proper height and tightened down on the threaded rod. I could do the same process with the upper section in its adjusted position if need be, however, this technique is the one that I now use.  Also, if the sections being joined with the biscuit don't quite line up laterally, I use a short section of threaded rod to force the joint to the proper location.  This is still a problem that I discovered when building the first helix.  It could be related to the curves on either end of the straight section being slightly different. 

   

Thanks for reading the saga of the spline helix.  Please don't hesitate to ask questions.  After the second one is completed and in position I will get back to building the rest of the new layout.