FUTHER HELIX QUESTIONS?

[Robby]

I install my cork and track after the helix is complete.  I've done this for three of them now.  I draw a circle using a circle template cut from masonite to the correct radius.  Glue one part of the cork to the outside of the drawn circle using white glue and small brads tacked down using a pair of pliers turned on their side as a low profile hammer.  Glue down the second side of the cork in the same manner.  Track is then installed using atlas track nails, sections are cut using a flex motor tool and soldered with feeders after every other 3' flex track section.  I'm 6'3" and have very large hands and this has never been a problem for me.  The suggestion to do it as you build is a good tip for certain but doing it post construction is not impossible either.

[ndbprr]

You don't ask but you also need to install track on each section as you install the next section.  Otherwise you either have a very diffcult job of reaching in and doing it or dismantling it to do it. I agree withe the trapezoid method.  if you don't understand the geometry draw inner and outer circles for the helix and extend straight lines like pie slices from the center of the circles past the outside of the circle.  now draw a straight line between the lines from the center so they go from one line at the inner circle to the next one right where it touchs the inner circle.  Now draw a straight line that just touches the outer circle at it midpoint between two lines from the center and extends to the two straight lines coming from the center on either side of it.  Now you have sections that have all straight lines and are duplicates of each other that can be cut with a circular saw, table saw or radial arm saw.  You can also lay out your sheet of plywood to maximize the usage of the wood and reduce waste.

[Pruitt]

For my N scale helix I used full circles.  I know there is more waste this way, however a friend of mine owns a cabinet shop and cut the circles on the CNC machine.  Each circle is exactly the same, it made laying out the helix much easier. 

Having cut all my semi-circular subroadbed by hand (well, with a sabre saw), you should believe me when I tell you how incredibly forunate you are to have it done by machine! You should immediately go buy a lottery ticket.

[ldrake26]

For my N scale helix I used full circles.  I know there is more waste this way, however a friend of mine owns a cabinet shop and cut the circles on the CNC machine.  Each circle is exactly the same, it made laying out the helix much easier. 

To support it, I am using threaded rod with 1/16" steel between them.  I also put a nut above and below each plate so that it would be easier to fine tune the incline.  The reason I decided to use the threaded rod vs. cutting spacers is that I thought it would speed up assembly because I wouldn't have to set up a stop block and cut all the spacers then screw them all in.  

 Each circle is 5/8" plywood.  To connect the ends together, I just glued and pocket screwed them, that way I wouldn't have an additional 1/4" splice underneath each joint.

Oh, and for those of you who are worried about the waste from cutting full circles, fear not.  They are perfectly round and will make great pub tables with the addition of a pedestal and some paint.

[KingConrail76]

All great suggestions....one more though...PLEASE STOP USING ALL CAPITAL LETTERS IN YOUR POSTS....some here may be hard of hearing, but we can see just fine.

Thank you in advance.

[EMD NUT]

I have a double track helix with 48 and 46 inch radius - both side by side on the same piece of 3/4 inch plywood.  I built mine in a similar fashion to the one in the article, except I ended up with three pieces per circle.  This was due to the diameter of the piece, and my desire to get more than one piece out of a 4 x 8 sheet.)   I installed once single section at a time.  Like the article, I used the side blocks to maintain my grade.  As a way of tying the helix together, I used a piece of 1/4 inch plywood on the underside of each joint.  This thing is rock solid and has operated flawlessly.  Good Luck with your project.       

[Pruitt]

I built my helix with semi-circles of 1/2" plywood. You can see one here, run up to the top of the threaded rods I used as supports, and one at the bottom, ready to be run up:

I used semi-circles because, with a 46" outside radius on the subroadbed, I could just get one semi-circle from each 4X8 sheet of plywood. The inner half-doughnut hole is big enough that I cut it into strips for straight subroadbed in some spots, and the scraps I use as splice blocks.

Here's my helix construction thread: http://www.thecbandqinwyoming.com/CM%20-%20Behemoth%20Helix.htm

[Robby]

I cut mine in arcs out of the 1/8 Lauan (sp?) plywood.  Using AutoCAD, I generated a pattern that resulted in little (but some) waste.  The trapezoids method is more plywood efficient but results in more glueing/clamping than I wanted to deal with.  Using my method allows me to get about 1 1/2 turns or so out of a 4x8 sheet.

Here's a link to my helix under construction.  It's a three level layout with the helix taking the middle level up and down. The first pic is the plywood pattern I used to cut out the sections.  Page down to see the heliz construction and also the second page.  These arcs are laminated together using carprnter's glue and clamped until the glue sets up.  I built the entire helix in about a week over the Christmas holiday.

http://s226.photobucket.com/albums/dd247/robby-ky/CV%20Subdivision%20Layout/

Robby

[Vail and Southwestern RR]

We made ours as a hexagon of trapezoids, there's pretty much no wood wasted that way, and no circles to try to cut.  But, if I was doing it again, I'd be tempted to go with 1/6th or 1/4 circles in 3/16" plywood, overlapped together to give a solid 3/8" helix.

[BigRusty]

You would create a lot of wasted "dougnut holes" using complete circles.

I recommend using 1/3 or 1/4 of a circle nested on the plywood sheet to save waste. I would use 1/4 inch ply and cut two sets. By gluing them together offset by 1/2 of the arc, you will have a very strong assembly of a continuous grade.

Assemble each tier, lay the rail and then keep going up.

[tjerrard]

I think it depends on the construction you are doing. In my case I cut half circles because I had lengths between each end of the helix so my helix was oblong and not a circle.

I too model in N scale.

Tom 

[MOSEMAN]

WHEN CUTTING FOR THE HELIX DO YOU CUT COMPLETE CIRCLES OR SECTIONS. I NEED TO BUILD A DOUBLE TRACK N SCALE HELIX. I AM AWARE OF THIS MONTH'S ARTICLE BUT I CANNOT DETERMINE IF COMPLETE CIRCLES ARE CUT AND THEN SPLIT OR COMPLETE CIRCLES CUT THEN HALFED,ETC.

THANKS

MOSEMAN