why no climbing sticks out of round aluminum tubing?

[raisins]

The round aluminum is significantly stronger/stiffer pound for pound (supporting itself like an arch from all directions) when compared to square cross-section tubing, or am I wrong here?

So why does no one use it for sticks? Too hard to work with and so you'd have to bend and weld it?

Just curious. Or am I wrong that the round is stronger/stiffer?

 

[RidgeHunter]

Interesting, I’ve never thought about this.

 

[Cyder]

I think it comes down to few different reasons.

1. You would have to machine all custom parts as currently most sticks use square, adding cost.

2. Round is stronger to perpendicular crush forces but rarely will climbing sticks encounter such a direct force (unless a bolt is over tightened) so you only get minor strength advances.

3. You would be remaking something that is very simple as is. When is the last time you heard of a stick failing? Surely it does happen but in very rare situations.


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[Vtbow]

Gorilla make round sticks for a while. Also, a long time ago Remington did as well.

 

[raisins]

I think it comes down to few different reasons.

1. You would have to machine all custom parts as currently most sticks use square, adding cost.

2. Round is stronger to perpendicular crush forces but rarely will climbing sticks encounter such a direct force (unless a bolt is over tightened) so you only get minor strength advances.

3. You would be remaking something that is very simple as is. When is the last time you heard of a stick failing? Surely it does happen but in very rare situations.


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I'm thinking that it would also be stiffer when under a typical climbing stick load, isn't bending a type of smaller scale crushing, etc?

I am not wanting to keep the same weight but make it stronger, I would want to keep the same strength and make it lighter. Sorry if that was unclear.

This search gives mixed results and it seems it varies by application.

square vs square tubing strength - Google Search

 

[Cyder]

Have you seen the out on a limb sticks? Machining May be a more practical and safer option.


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[raisins]

Have you seen the out on a limb sticks? Machining May be a more practical and safer option.


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Agreed, but I'm trying to parse this into how much of this is a practical/money decision and how much is physics/strength/engineering. I might make people's quest to use carbon a bit less necessary, etc.

I could be totally wrong and a round stick would stink and offer no advantages when it comes to strength.

 

[smcchevy]

If the diameter of the tubing is increased, there is a point where the section modulus is roughly the same. I used a 1" square tube with an 1/8" wall as a baseline. If the round tube of the stick was 2.5" in diameter with the same wall thickness then you would have increased stiffness and roughly the same weight but have a bulk/ stacking penalty.

I think the downside to a round stick would be the connections (steps, standoffs, and strapping method) since you want to load the outside edges of the tubular section it would be harder vs. the flat sides of the square tubing.

 

[raisins]

If the diameter of the tubing is increased, there is a point where the section modulus is roughly the same. I used a 1" square tube with an 1/8" wall as a baseline. If the round tube of the stick was 2.5" in diameter with the same wall thickness then you would have increased stiffness and roughly the same weight but have a bulk/ stacking penalty.

I think the downside to a round stick would be the connections (steps, standoffs, and strapping method) since you want to load the outside edges of the tubular section it would be harder vs. the flat sides of the square tubing.

I'm thinking something like the Mantis stick

The Mantis Climbing Stick System | X-Stand Treestands

The Mantis

x-stand.com

but the whole thing out of bent/welded round tube aluminum.

If you can achieve greater stiffness with the same weight, then it seems like you could use the same idea to save some weight while maintaining acceptable stiffness.

 

[smcchevy]

Like muddy stagger steps? I think someone on here has fabbed a few but can't remember who