Tim Horton's Helix

[John]

As Lemosteam said: "Then you would have only needed a nut on the top and bottom with everything sandwiched between".

The conduit or pipe would act like the wooden spacer blocks except you would need to glue or screw them.
That makes a lot sense, great idea!

I just used glue .. seems to hold my helix together pretty well ...

[Scottl]

Thanks Allen, I get it now.  I did not read carefully enough.   

[jagged ben]

I think the point of the threaded rods is that you have adjustability at any point during (or after) you build the helix, and you are not relying on spacers or perfection at the bottom.  In some cases you might even be able to add a layer after the initial build.  Having to fix a mistake on a helix with spacers could potentially take as long as threading all those nuts.

If I were doing this, I think I would try the following:
-pre-assemble most or all of the roadbed so that is all laid on top of itself
-put a nut and washer on the end of each threaded rod and start it through the top layer
-work down the next layer, creating the approximate spacing, and leaving the top nuts loose in between the layers
-use a drill chucked to the end of the rod to systematically work the rods down through the helix one layer at a time (low speed!) threading nuts as I go.  Presto, helix is built.
-put the thing in place and systematically adjust the layers to final height

Maybe someone has tried this and can say how it went.

I've probably threaded almost a hundred-thousand nuts and washers in my life.  If I were doing such a project, I think I could stand threading a few more.

[rsn48]

The photo I took wasn't an image to illustrate a "how to..." but a playful image that I quite liked, especially with our mutual friend in the helix taking a photo to help in "how to...." though he himself has built a helix; he was shooting as he liked Tim's helix as well.  There is a famous photo, I think of Admiral Rickenbacher and I believe published in an old Life magazine, taken standing on a ladder in a nuclear silo; when I saw Tim's helix that photo came to mind and I wondered what the image would look like if I just pointed the camera down and hit the shutter.

I agree that Tim is very meticulous and his layout is well planned out in advance and his electrical is excellent.  And his historical knowledge of his chosen RR is probably the best or one of the best in North America - PGE and BCR.

[craigolio1]

I really like the threaded rod as well.  With spacing as little as 1.5" in N scale there isn't much finger room.  If you needed to do a track repair, and Murphy's law says it will happen right in the middle of your helix, you could theoretically get an extra 1/4" or so extra out of the top and bottom by raising and lowing the levels a bit.  Probably unlikely but I see it as a benefit over a completely rigid structure.  However for ease of building, the conduit idea sounds promising.

How about this.  Instead of threaded rod use wooden dowel.  Build your helix a circle at a time.  Slide a circle down over the rods.  Use a set of six or so spacers and glue the layers to the rod (glue put on the rod then slide the piece down over the glue.  When dry take the spacers out and do the next level.  No nuts, equal spacing, looks nice.  Very permanent though.

Craig

[Lemosteam]

The adjustability is a nice factor to consider.  I agree Jagged Ben.  Body u washers (body shims) could also be used to that effect by loosening the nut at the top and inseting the washer and retightening.  Lots of ways to skin a cat.

As another woodworker, if builing in quarters as you suggest, a biscuit joint could be used at the end of each quarter to align each panel's track surface and then the rods would not have to be near the joints- there could be two spaced in the middel of each quarter with the bicuit between the adjacent rods.

[Bendtracker1]

Lots of ways to skin a cat.

Agreed!

As another woodworker, if builing in quarters as you suggest, a biscuit joint could be used at the end of each quarter to align each panel's track surface and then the rods would not have to be near the joints- there could be two spaced in the middel of each quarter with the bicuit between the adjacent rods.

Since you brought up biscuits, we did think about using them.  Sometimes biscuits do not fit tight enough to keep them lined up due to the varying thicknesses of different manufactured biscuits, if the blade is new it might leave a thicker cut or if you wobble the joiner a bit while making the cut.  So we opted for the screwed and glued scabs as we thought it might offer a smoother transition between quarters and it reduced the wait for drying time: glue, clamp and screw then we could move onto the next one.

This is basically how we laid out the quarter sections and the holes for the rods;
 

Now this is not to scale, the actual helix worked out to be about 28 or 30 radius.  We chose to cut out quarters to reduce the waste factor for each sheet.

[Lemosteam]

  Sometimes biscuits do not fit tight enough to keep them lined up due to the varying thicknesses of different manufactured biscuits, if the blade is new it might leave a thicker cut or if you wobble the joiner a bit while making the cut. 

You are correct sir!  This why I like using ripped splines to fit the groove of the cutter instead of the actual biscuits.

[superchief]

here is a picture on my helix using the wooden block method



and again the threaded rods can be adjusted later if needed/ the wooden blocks the first level needs to be perfect and all the blocks ripped at the same time without adjusting your saw. both are great ways of building a helix. Gordon/ Santa Fe-all the way

[superturbine]

But Gordon show them the scene on top of you Helex!

[wmcbride]

Tim is a meticulous and skilled modeler and I have followed his construction with great interest.

I am thinking or revamping and going to two levels with a helix, possibly the larger of the Ashlin offerings.

For those of you using vertical easements to ease an abrupt track change from level to, say, a 2% grade, how long of an easement do you build and what do you use? In the past, I have just sanded down cork roadbed when going from the mainline to siding or yard tracks laid directly on my "ground-level" foamboard.

Thanks for any insights.

Bill McBride

[superduperchief]

This is a very informative thread. Thanks everyone.