z axis loosing steps

[ptjw7uk]

I have also been pondering on adding threaded rod to add tension to the column but I have not seen this done anywhere or at least not reported on the web.
I really must test this to see if it has any effect, I know it has effects upon brick walls and concrete makes them stiffer!

Peter

[der_fisherman]

I helped a friend about a year ago with a similar problem, we installed some constant force springs to counterbalance the Z-Axis, we did it very "empirically" and weighed the Z Axis and installed two springs, but only connected one for 2 Kg. as that is what it weighed, but as he wants to eventually change to a bigger router, we just left the other one unconnected for the moment!!
Now his Z-Axis is just about neutral we believe, or fairly close.....
The springs were wound onto ball bearings with "side cheeks", sorry I do not have fotos and he has since sold the machgine, but it worked just fine after that.....
The constant force springs (I am told) always exert the same force, they do not increase as they get longer as normal springs do, which is a big advantage,,,,,
You can see them and read a good explanation here:-
http://www.leespring.com/int_learn_c...ce_springs.asp
originally I wanted to use a counterbalance, but the springs were simpler and added far less mass......