Cody - Spring question

[David Delaney]

I am getting close to having to install the springs - would bed springs work, they seem pretty strong!?  If I add more springs, will that help carry more weight?  Thanks

[Tom Wills]

Bed springs are compression springs, meaning they resist being pushed in. You want Extension springs, meaning they resist being pulled out. Yes, more springs in Paralell will help make an arm stronger. Like this:

|sssssssss|
|sssssssss|
|sssssssss|

where the "s" things are springs. Put something like that across an arm, and it will be much stronger. Putting springs in series (one after another) will not help though, it just makes it longer and lessens the tension on each spring.

Good luck with your rig!

[David Delaney]

No, I was thinking of the springs that hold the box spring together, those springs are extension springs and they are strong buggers, I just don't want them to be too strong.

[Tom Wills]

I think at the very least you could try them. The worst that'll happen is that your rig won't boom or absorb any shock.

[Phil Kindred]

Check  members systems forum and look for Phil's progress.  I use drawbar compression springs and swear by them.  They are , in my opinion, superior to extenstion springs.  There is also a video posted of one section of the arm in motion.

[Tom Wills]

I may just have to look that up, because I quite simply have no clue how that would work. Hmm...

EDIT: Oh, that's how it works. Well, quite interesting way of doing it. I might try that eventually.

[Charles King]

David to add to what everyone has said:

Using more than one spring does:

1. Increases weight bearing capacity of the arm but this also depends on the characteristics of the springs in question.

2. Doubles the longivity of the springs.

3. Increases friction in the arm ( especially when cables are used to connect them).

4. More springs in the arm acts more or less as a cut down version of using just one long spring to get a smoother ride throughout the entire boom range of the arm, without exerting extra pressure on the springs; compared to using just one spring. This is more dependent on the specification of the spring than the actual stabilization of the spring in use.

5. In conjunction with no. 4. It is also an advantage when you want to maintain a decent size arm without it being too long. In short, you might feel a length of 25cm is better than 30cm per section. Then again, this all depends on the ratio you will be working on. Just remember everything is dependent on numbers or specs of another part of the arm. That's why bulding is not always that easy or simple. But the process is fun if you are willing to understand the logistics of building a stabilizer system.

6. Compression springs are better than Extention springs. Extention springs are more prune to wear and tear quicker than compression springs.

I hope I havn't been too technical.  BTW, did you get my  third book? It's called 'Things you should know before building a full rig' It discusses things like this.

[David Delaney]

Thanks Charles.  I've got Cody's book about 2 months ago and started workiing on it then, so I might be too late for yours!  I am too far into the Cody's original arm plans to go for the 3 springs system (I think, if someone can tell me how to mod. his original design, then let me know!).  I made a wooden prototype with the springs from bed frame and they are strong, almost too strong but I will have to wait and see what the overall weight is like when I am finished everything.  I don't know what type bed frame springs are - extension or compression - what do you think?