Hi,

I finished the conversion of my BF20L mill. Haven't cut anything yet because I don't want to run the machine without the counter weight on the column.

Stroke of the Z axis is around 260mm. I haven't measured the spindle head but it is something like 30kgs. I have a 2005 double ball nut on the Z.

So, a pair of air strut is easy to install however I have concerns about reliability of these because when they fail the machine will continue to work as it does and I won't know that the strut doesn't work anymore.

A simple pulley system sounds more reliable but I don't feel OK about doubling the weight on the column. However adding the third pulley will half the weight so it is a little more better.

I have no idea how the hydraulic counter weigh systems works on commercial machines. And I don't know if they are available for smaller machines.

I would like to hear your opinions about this so I can decide.

Best,
Suat