How to limit bending of cable rail posts

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Here's a picture of a cable rail job I did, naturally under tension all of the cables exert a lot of pressure, I used aluminum 1.5" square  1/4" thick wall tubing, I can't get tubing any thicker wall than that, and it still bent quite a bit in the center.Any ideas on how to limit that bending? I could use solid posts, but thats quite a bit more expensive.Also it wouldn't work on the corner posts.I'm doing a stainless job soon, and I won't be able to get the tubing in 1/4 wall so I'll have to use 3/16, and I'll have the same issue


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Reply:Do you have design control? You could use modified end posts or flat bar with horizontal bracing.I was sent a binder from a vendor with design specs.  The suggested 1/4” wall x2 minimum for stand alone posts.  Around here I do not think anybody got the same binder.  Lots of pathetic cable rails. Sagging cables and bent post.  Massive jobs,too.A jibe close to my shop was heavily modded after installation. It look better now.  Also, how are you tuning them?Last edited by tapwelder; 5 Hours Ago at 10:12 PM.
Reply:I make all my own posts, so no vendors involvedSent from my SM-G973U using Tapatalk

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Reply:Got you.  I do too.  It was not about the post. It was the information.  It was a great resource.  Cable rails are deceptive in design. I will dig it up.
Reply:What size and kind of cable, how is it held and tensioned, and how does it run/is it placed/snaked through the corner post? Who decided on the design and does it need to meet any specifications for strength, etc. or just look good? What if you used a smaller tubing piece that nestles inside to give some added stiffness?
Reply:

Originally Posted by Oldiron2

What size and kind of cable, how is it held and tensioned, and how does it run/is it placed/snaked through the corner post? Who decided on the design and does it need to meet any specifications for strength, etc. or just look good? What if you used a smaller tubing piece that nestles inside to give some added stiffness?
Reply:Bigger tubing or thicker are the only ways you are going to make the post stiffer.  Or use steel/SS instead of aluminum as it is 3x the modulus and will not deflect as much.  You can use rectangular tube with the longer direction in the tension plane to help you even more, but that won't help in corners.  Instead of 1.5" sq use 1.5" x 2" or 2.5" rect. (if you can get it).  In the corners you would prob need to use square tube of the larger size (2 or 2.5 sq).The only other alternative is going to be bracing it with something else to stiffen it.  I'm guessing few of these options are what you want to hear...-DaveXMT304 with: 22A Feeder, or HF251 Hi Freq DC TIG air cooled
Reply:Could you roll a slight crown into the post. Putting some camber into those posts is about the only way to prevent that bowing. Determining the amount of camber should be fairly easy if you measured the now on one of the " bent" ones.
Reply:

Originally Posted by M J D

Could you roll a slight crown into the post. Putting some camber into those posts is about the only way to prevent that bowing. Determining the amount of camber should be fairly easy if you measured the now on one of the " bent" ones.
Reply:

Originally Posted by M J D

Could you roll a slight crown into the post. Putting some camber into those posts is about the only way to prevent that bowing. Determining the amount of camber should be fairly easy if you measured the now on one of the " bent" ones.