Constant Force Spring for Counter Balance

[biomed_eng]

I have read a few posts about using Constant Force Springs as an axis counter balance, usually a z-axis counter balance. Like these: www.vulcanspring.com/mechanical/stock.html

However, I have not yet seen pictures or read of anybody actually using it in their home-made cnc machine. I have mainly seen people using gas springs.

Have you or have you heard of any real world experience with Constant Force Springs as a Counter Balance?

[Rance]

When I get around to that part (the Z axis), I plan on using a pneumatic counterbalance & a 2-litre bottle for air.

[wcarrothers1]

The first time my gecko's fault out and my Z drops it's way to my work piece I'll give some thought to spring..

What I was thinking is putting some sort of resistance brake of some sort to stop the screw.. Some times if the motor isn't holding it will drop and some times there is enough resistance as it sits to stay in place.. so I'd only need a small spring.

b.