Helix

Probably threaded rod would be easier to adjust, and if the unthikable happens (like a major screw-up with the grades) will be easier to correct (surely beats tearing everything down and rebuilding). My 2 cents.

I'm a fan of the threaded

I'm a fan of the threaded rod.  My helix is supported by 6 3/8" all thread rods with oak support cleats.  Works great, but I would probably use 8 next time and stagger them (one outside, one inside, and so on...).

Hard to beat spacer blocks for ease of use

One only needs to get the first turn set up at the right gradient and the rest are automatic.

If you use threaded rod,

If you use threaded rod, consider SLOTS and not HOLES for the rods.  It would be much easier to set up all the nuts first while not on the benchwork in an aproximate location than to spin them all down from the top once the rods are in place.  Ask me how I know??? (smile)

Rods and Nuts

Sean has hit on a big issue when using threaded rods. How does one get all the nuts in place without completely losing ones sanity and resorting entirely to vocabulary learned while serving in the military?

One guy, I think it was Mark Brunton, put a 4" diameter (aproximately) softrubber disk in a drill motor and using its edge on the sides of the nuts to significantly speed up this process.

Byron does make an excellent point though, that although it's kind of low-tech, the spacer blocks make it very easy to add additional laps - once the first one is installed and completely tweaked into position - each successive lap just sits on the spacers.  No adjustments required.

To get the nuts in the right place on the rods, it might be a good idea to make spacers and use them to hold each lap in place while the nuts are adjusted and tightened.

Question:  If you've used the threaded rod approach, did you tighten the nuts down on top of the helix roadbed directly, or did you use little wedge-contoured washers so the straight up-and-down rods/nuts would have a level surface to sit upon rather than the sloped surface of the helix roadbed?

Cheers,

Charlie

I used regular washers top

I used regular washers top and bottom of the plywood.  Once the everything was adjusted and the way I wanted it, I tightened everything down good and put a small drop of ca on each nut at the thread.  Worked fine.  I eventually had to remove the layout, but the helix lives on at someone elses home...I gave it away..It was picked up by a friend of the new layout owner on a long haul flat bed truck... strapped down and survived the ride well!    I hope they are enjoying it!

What scale is your Helix...

Hey Sean,

Nice effort on the helix.  What scale is it HO or N (looks like N)?  And what radius did you use?

I also noticed that you have a small straight section in the middle, was this to reduce the drag whilst trains are negotiating the helix?

Cheers,

Jason...

Spacers

That's how we generally do things at my club. You want a consistent vertical separation between turns anyway, and spacer blocks cut to a consistent size is the best way to ensure that.

Like Byron says, getting the base turn correct is absolutely critical, and then each subsequent turn just falls into place. Just don't rush the tracklaying because it's crucial that it remains smooth and problem free. That's not the place you want to be doing maintenance and repairs later on. Also wire each turn as you go.

If you keep the spacing to a minimum to hold grades to a minimum, if you find at the end the grade is wrong, the only solution is to destroy the whole thing and rebuild it with a larger radius, whether you've used spacers or rods, it doesn't matter since you can't decrease the spacing past a certain point.

Jason,  Thanks!  It was

Jason,

Thanks!

It was n-scale Atlas c55 track.  If I recall correctly, the radius was 18" and there was a 12" strait section.  I wanted to reduce the grade some and had more length than width to make a biger radius.  It performed very well and I would have kept it, but it did not fit my current layout.

The link is to a series of pictures that tell the construction story pretty well... they are not in the correct  order though.

http://www.pegnsean.net/pics/trains/new_tba/helix/

Thanks for opinions

Thank you to those that answered my question.

I was leading towards using the fixed spacer approach and have decided my helix will be built that way. 

Thanks

Steve Raiford

I think the fixed spacer

I think the fixed spacer method is a good choice. It is how I built my current 3 turn helix.  I have to say the strength of a threaded rod helix is amazing.