Measuring flex track on curves (to size)


N

Necrosaro420

Member
How on earth do you measure correctly flex track going around a curve so that you can cut it to the right side? I am trying to make a curve and for the life of me I cant get it correctly to line up at the ends to connect to the next piece of track lol.
 
There are some tips/tricks:

First, you can actually permanently bend flextrack so that it stays curved at a radius. This is especially important at the very last two inches of any length you have...either end. It takes some learning, but if you try it, say around a wide pole, you can get it to take on a permanent radius.

Many would not have the heart to tackle this part of the hobby.

The best way to do this is to place the straightened pieces on a bench, aligned so that they are both tangent to each other, and solder their joiners right there. Then transfer the two pieces to the layout. One other tip is to slide one of the sliding lengths into the other by about six ties, and solder the joiner there...or try it without a joiner. A wide enough curve may not require the bond of a joiner because the spike head details will make it curve with the rest of the flextrack. If you do the slide and solder, you'll have to accommodate the thickness of the joiner by either grinding away some of the tie(s) surfaces or actually removing a tie or two and then re-inserting them, suitably ground down, later before you ballast that location.

Or, you get the curved length you want into place along your pre-drawn centerline, and you spike it down well. Then you add the second length with the joiners and spike it into place along its part of the centerline. You continually make sure all four rail tips are touching....always go back before you do any cutting and check that the ends are aligned and either gapped according to your desires or actually touching. The sliding rails like to part just as you get your curvature right and begin to fix it all in place, particularly if you use latex caulking as I do.

If your rail ends want to straighten, you can drive a drywall screw tight to the inner rail, being careful not to crimp or bend anything. You force the joint inward toward the centre of the curve until it conforms to your centerline, and then you can drive another screw into place on the outside rails. When you go to ballast it all, you can remove the screws when it is dry and is holding the rails in place. You tidy up the ballast later after you remove the screws.

Basically, you use your noggin. Try stuff, being careful and patient with your tools, the rails, and yourself. Don't push hard or over-long before you put your tools down and go away for a couple of hours or overnight.

-Crandell
 
Modern flex track, the kind with plastic ties (at least the brands I've been using) do tend to straighten out. Bending them around a large diameter tube or rod...or even the steel support poles in your basement...probably won't get them to stay at the curvature you want. I agree with Selector that you can solder the rails of one end to a piece of tangent (straight) track and then curve the flex track, but I've just finished laying track on my new layout and haven't soldered any joints yet. (I probably will to maintain good electrical continuity, when I get around to wiring the layout.)

The main thing to do is get your roadbed in place first. If you are using cork roadbed, then lay out the centerline of the curves on the sub-roadbed, and align the cork halves to the centerline marking. I prefer to either tack the cork in place temporarily or use a staple gun with 5/8 or 3/4" staples. I don't glue it down yet. I make sure the roadbed is going where I want it to go, and then, one half at a time, glue it to the plywood subsurface with white glue or construction glue. Then, starting with the straight tract, I start laying the track using "long" (that's what the package says) track nails that go clear through the cork and into the plywood. You will probably bend quite a few of these before pushing them home. I use a needlenose pliars, grabbing the nail as close to the point as I can and still have enough exposed to hit the plywood under the cork.

When you get to a curve, just start bending the flex track and nailing them in as you go. Allow the free rail (the one that slides in the plastic ties) to slide along, changing the apparent length relative to the ties as it will. THERE ARE SOME CURVATURE FORMS YOU CAN BUY FOR VARIOUS RADII CURVES...18", 20" and 22" at least. They are aluminum and fit between the rails. Bend and nail until you get to the end of the curve. Don't try to cut the track to length until you've finished making the curve. If you are also using flex track on the straightaway, simply slide the free rail so it matches the end of the other piece. If you have to cut away some ties on one piece or the other, do so. It is NOT necessary that the ends of both rails of the curved flex track be opposite one another, unless you are tying into a turnout or other fixed track. If you are, simply lay the turnout on top of the flex track, so you are touching the shorter rail on the curved flex track. Mark the location of where you need to cut off the rail that is sticking out the end of the curved flex track, and cut it with a razor saw or a carbide cutoff wheel in a motor tool. (If the end of the flex track is loose enough and you can get at it, you might also use a Xuron track cutting tool, followed by filing to clean up any burrs.)

Frankly, for curves much sharper than 24-inches, I prefer using sectional track. Atlas makes 15", 18" and 22" radius curved sections. For other sizes (I use 20" radius on my main line due to space requirements), Walthers has Shinohara track available in other radii sizes from IIRC 9" to 30-some".
 
What im meaning is ok if you lay a piece straight, all ends are lined up together, when I start to curve it say to the left, the left rail is obviously going to be sticking out alot further than the right rail. Im connecting a curve onto a straight point just unsure how to measure to get that correct since everytime I have tried it tends to look very sloppy lol
 
I've always felt that laying flex track along curves was the biggest challenge I ever faced when trying to get "bulletproof" track. The tighter the radius, the worse it is. How I did it and my recommendations:

I first concerned myself with making sure I had one end of the flex track very well secured to the next section of track. Then I would slowly bend and fasten the flex track, always making sure to keep ties spaced well and that all important first connection very solid. Be slow and precise, a few extra minutes now saves hours of headaches in the coming years.

I concentrated on maintaining that good first connection and making a good curve, then after the section of flex track was down I would test fit the next piece and use my rail nips to trim as needed. If you are trying to pre-cut and measure I think you are setting yourself up for a nightmare of frustration.

Something I learned to avoid was ever trying to connect flex-track sections to each other in the middle of a curve. IMHO it's best to have a piece of rigid sectional track in between them.
 
Here is my understanding of what you are asking: on a curved piece of track the length of the two rails will be different - how do I know what those lengths should be at a given radius over a specified degree of range so I can cut the inside rail to length and have it line up appropriately? Or, how do I compute the length of the two arcs (http://www.mathopenref.com/arclength.html).

You could mathematically compute this, or you could lay it out then cut the ends after marking them using a straight piece to position your marks.

Or I have no idea what you're asking ... ;)
 
You must log in or register to reply here.



Back
Top