Large Scale Central

Rail benders and bending theory

Track and Trestles
#1

I am sure this is one of those topics that has been asked and answered a thousand time but I am asking it anyway. My thoughts and plans have moved indoors and as such I need to bend code 215 aluminum rail down to 30" diameter curves. I will be hand laying on my own ties. First what benders are out there and which of them will do a good job of getting rail down that size curves.

The second question is on bending theory or practice. I assume when we are talking curve radius we are referring to center line, at least I am. Which means that neither rail in a curve is bent at the stated radius. Is there a simple formula or way to know what radius each rail must be bent to for a given radius curve to maintain gauge? How critical is getting the rail bent to an exact radius, or does close enough work and then when you spike it down you massage it to the appropriate place to meet gauge?

#2

Devon,

Center line should always be used when denoting Track diameter or radius. That’s also where you should measure length.

Unless the rail was annealed to ‘dead flat’ there may be spring back. Bend farther and then undo as needed.

Check with Robbie at RLDs to verify minimum bend. They made some that are comparable to the more expensive Train-Li, Both are dual rail benders. Aristo made a single rail bender which is a tad trickier to use and have the gauge set. Perhaps you should have a length of ties for bending 2 at a time.

Stainless steel needed to be more precise than more flexible rails. There is some give. Learn as you go, eh?

John

#3

Well dual versus single benders. . . intuitively a dual bender makes sense for bending assembled track. But can you bend two loose rails at a time? I see where a dual bender would be set to a center line and then each rail would be bent accordingly keeping gauge. So do you just feed the rail in one at a time one inside then one outside? I was intitially thinking I would have to have a single bender but know I see where that may not be the case.

#4

Devon: Check out sunsetvalleyrailroad.com they carry a single rail bender that works quite well. I use mine to bend .332 LGB Brass rail for the out door rr. I would suggest that you cut some templates for the centerline radii you are going to be using. Paul

#5

Paul,

Ty suggested the same bender. One question I have is its effectiveness on bending 215 rail. I mean it is specifically designed for 250 or 332 rail but would the 250 wheels bend 215 track. Not really knowing how it works it seems like it wouldn’t, is the little lip on the wheel going to fit in the groove of the rail? I realize there is not a whole heck of a lot of difference between the two but I don’t know how tight the tolerances are on the bender. Now I am not necessarily stuck on 215, its what I want, but not at the expense of having to get crazy in order to use it.

#6

Devon Sinsley said:

Well dual versus single benders. . . intuitively a dual bender makes sense for bending assembled track. But can you bend two loose rails at a time? I see where a dual bender would be set to a center line and then each rail would be bent accordingly keeping gauge. So do you just feed the rail in one at a time one inside then one outside? I was intitially thinking I would have to have a single bender but know I see where that may not be the case.

You speed reeders! (spelt that way fer you)

“Perhaps you should have a length of ties for bending 2 at a time.”

Gee wilikers Wally!

#7

Oh sorry John. I read that but didn’t really grasp what you were saying until you repeated it. Use a section of ties. . .assemble the track, then bend it as a section . . . then separate it . . . then lay it by hand. . . rinse and repeat. That would work.

#8

The price of a decent dual rail bender is a bit to choke down $200-over $300 and this is 90 +/- feet of track which will run me $100 bucks. But the time savings, accuracy, and the fact that I will also be doing the outdoor track someday it would be a solid investment. Now if I could only figure out how to make 990 hand hewn twig ties efficiently, that’s another story for another day. I may regret/change my mind on that one before its over.

#9

no train club nearby that you can borrow the bender from? I think we had this whole discussion before??

By the way, even with SS rail, just bend the track to the radius you want it will flex to fit for inner and outer. unless you are bending really tight.

Then it’s clear that the radius for each rail is your base radius and either plus or minus 45mm /2

Greg

#10

Greg,

I don’t believe I have had this conversation, if I did I have plumb forgotten it all. Maybe a while ago it came up in my outdoor discussion as a side wild tangent but I don’t recall ever getting as far as actually bending the rail. I do know we discussed making the track base and then bending rail to fit it but not really the mechanics of how that would be done.

I hadn’t considered the borrowing aspect, thanks for that suggestion I am sure there are several in my club. And as to the math, Duh! I don’t know why I was trying to make that harder than it was, that could be because that’s how I do things. I have never been accused of oversimplifying.

#11

We like and been using the Train - L binder and will almost do any kind of a bend ( If you can get ahold of one to use or own.) on a single rail, if using washer for shims on the rollers.

We even bend HO rails ( Code 100 N-Silver ) for laying in curved bridge guard rails and building odd track SW’s. to fit into a tight area.

Course if you are trying to bend a rail shorter than 7 or 8 inches it probable won’t work

The binder will just about do anything you want and ya is works like a old wood working Tool, called a Shopsmith if you remember them. “Takes time to set up for the job you want to do but can do it.”

#12

I have a Train Li dual bender. That being said, it comes with 332 and 250 “dies or rollers” (For lack of a better word). I don’t know if 215 would fit.

It is designed to bend track already installed in LGB, Aristo, etc track. If you are hand spiking, you are going to have to bend your rail first. Aluminum rail allows for “fudging”.

So you will prolly need a single rail bender with 215 rollers.

#13

Noel Wilson said:

works like a old wood working Tool, called a Shopsmith if you remember them. “Takes time to set up for the job you want to do but can do it.”

I own one. Love it. Need to fix it.

#14

I have been sorta’ following a few of your threads. In this one your talking of using .215 rail and in another I believe your thinking of using small cars and engines (stock?) to run on it. Sometimes those over scale wheel sets have a little trouble running on that low a profile rail, especially through switches. Just something you may not have considered.

On rail bending and hand spiking.

As a little background for you; Through the years I have built 2 single rail benders, one from scratch and one from parts, as well as using a dual bender on many hundreds of feet of track in both code .332 and .250 in brass and aluminum. Also been down the road many miles on hand sawing Redwood ties and spiking rails of brass as well as aluminum, including building switches in both metals as well as Nickle Silver.

Some of the things I learned that worked best for me.

Dual rail benders are just that, to be used on duel rails held in gauge by tie strips. They work fantastic to curve or even straighten pre-assembled trackage. I don’t have one in front of me right now but I believe it would be almost impossible to run a single rail through it as there is no way to crank it through. The ones I have seen sit on the track and are pushed along by hand producing the curvature , I have found it best not to try to produce the final curve in one pass but to use multiple passes to bring it to the desired curve. Trying to hold a single .215 aluminum rail and push the device along, problematic at best.

Hand laying track I use a single rail bender to produce the curve required. The curvature is not critical especially for 215-250 aluminum because of the tremendous amount of flex in the material. Have your centerline on your ties and some good rail gauges, get 3 point gauges for your curves, and spike away. Always wide never tight, remember were talking thousandths. I know the experts throw lots of impressive sounding numbers around when it comes to back to back on wheels and gauge between rails but the fact is the very best wheel sets in the hobby are only semi-scale with over wide tire face and nothing from a factory is going to have consistant numbers even on the same engine or car.

Using a single bender especially on soft material like aluminum it is CRITICAL to keep the rail on a flat plane while bending. By this I mean keep the rail foot or head flat to the table and 90 degrees to the bender rolls. Letting it twist out of plane will produce, well a twist in the rail, not real noticeable to the eye but once it is spiked down flat it will fight the spikes and try to rise to the twist creating an out of gauge problem that can be difficult to figure out. Does any of that make sense?(http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-smile.gif)

Spikes. If your spiking outdoors do not use stainless steel spikes unless you are clenching them under so they can not climb out of the wood. Indoors they should work fine. Steel spikes rust and lock into the wood better, not perfect by any means but far better than stainless.

Just a few things that work best for me may or may not be of any help to you.

Rick

#15

Rick good points.

The flanges on many large scale wheels are around 1/8th of an inch. I say around because there are variations. 1/8th of an inch is .125, on a .215 rail, leaves .090 for the foot of the rail and the spike on the rail foot. That was the problem I had with my HOn30 track, I used a small code rail (code 40) and when I spiked it down the wheel flanges on my equipment just bounced from spike head to spike head.

I have used my large scale duo railbender to bend one rail, but it was not easy. And when I bent rails by hand I did get a twist in the rails, so I know that frustration. Yes, I used stainless rails, so its not the same, but its close.

And yes, on the curves a 3 point gauge, when used properly, will widen the gauge a little. That helps reduce binding in the curves. With the wide tread of our wheels, properly gauged wheels will not have a problem if the rails are a bit wide (the possible exception is switches).

Devon, take what Rick said, he has many good points in his post.

#16

So far on the 16" of spiked 215 rail I have down the Lil big hauler clears with ease. I am not 100% sold on 215 just 99%. If wheel clearance is my only issue and that is only and isue on some wheels then it is not an issue, I will trade out wheels. Unless there is some sort of glaring problem well thin I can be persuaded away. But the light rail is the right look I am after.

Rick I did track with all you said and thanks for the insightful information.

#17

well, for the umpteenth time. i do bend my rails with the hands and a small hammer.

and, as most of the track i bought, was R1 curves, i bent a lot.

about handlaying track, that is one of the advantages of largescale. nothing has to be correct to a fraction of a millimeter.

use some sleeper webbing as rig and off you go.

#18

Devon

Sixteen inches of track and hand pushing a car is a different matter than running a loco and cars around a layout and through switches and curves.

Not trying to change your mind at all, just pointing out some possible issues you may face so you can address them as you go not after the fact.

Korm

A very good option to hold rail ends in alignment ahead of spiking, used it myself.

Rick

#19

Korm Kormsen said:

well, for the umpteenth time. i do bend my rails with the hands and a small hammer.

and, as most of the track i bought, was R1 curves, i bent a lot.

about handlaying track, that is one of the advantages of largescale. nothing has to be correct to a fraction of a millimeter.

use some sleeper webbing as rig and off you go.

Korm

What are you using the horse shoe nippers for, cutting off the spikes below the ties??

#20

I would think that with most rail, especially light, aluminum rail you are talking, tat bending both to the nominal radius would work fine. Both would be slightly sprung and would balance each other. Like them a little wide and off you go. Going for aerospace accuracy is not required.

On the WW&F straight rails are laid on curves and just sprung into place. Some of our used rails are slightly curved, they are often used for straight track too.