MK2: moving gantry router for metal cutting - comments sought!

[paulus.v]

The rails are only passing on the vibration to the structure they are attached to. The box ways are great because there is always a layer of oil between the two sliding metal parts and it is absorbing 20x more vibrations than the linear rails (according to the info in the last link from my first post) therefore less vibration transferred to the structure.

Only the grey iron is very good at damping vibration. And it is due to the shape of the graphite that forms, the graphite flakes.
http://www.atlasfdry.com/grayiron-damping.htm

I've seen no springs in linear rails or blocks :) If you have the rails transmitting all the vibration to the structure it attaches to, then you have do something to kill them in that structure and steel is not good at that.

[m_c]

Linear rails rely on a couple rows of balls with minimal contact, and the balls/rails deform under load acting like springs. Off course, the big benefit with linear rails, is you can over spec pretty easily to minimise the problem.

As with everything, it's a case of picking the best compromise for your needs.