Sieg X2 head weight

[ecat]

I've no idea what the mass is. I bet John S knows...

I would make the counterweight a bit lighter than the head as that will ensure you still have force downwards on the Z-ballnut. This will eliminate backlash, except where you have a force parallel to the Z-axis which is greater than the imbalance (e.g. drilling).

I'm sure this applies when dealing with low friction linear rail but does it apply when dealing with the dove tail and gib set up used on these Siegs?

As a quick test, when the gib is snug is the head free to fall under its own weight? If the answer is yes then the above does apply, if no, then the weight of the head is insufficient to overcome the friction in the ways so there is no downward force available to eliminate the backlash.

From my experience with the X1, and possibly the X2 and X3 from what I've read, the head is far more likely to rotate about the lowest corner of the head dove tail than it is to fall smoothly down the column. And a gib tight enough to minimise this rotation results in more friction than the weight of the head can overcome.

Edit:
It was bugging me that I didn't specifically mention the 'quick test' should be done with the head free from screw! Just make sure to support the head on a wooden block or such in case it is free to fall!