Vertical moving gantry????

[rinderpest]

Snap! Mine are 550mm stroke tho. Very nice things; just not yet sure what to do with them. The ones I have are made by SMC.
Shame air is too springy to allow positional accuracy.
What do you plan on using yours for?

Back to the original posters question I would go for a movable bed too.
I saw a very handy post and/or image on cnczone(maybe?) that had a side view of a moving gantry machine with lots of forces drawn on it ie given 50N force on cutter then with n length of Z axis the twisting forces on the gantry will be (x)N.
It was well worked out and made the point you wanted the centre of gravity of the Z axis to be between the two gantry bearing trucks etc.
Saw it once, was impressed, and now I actually need it to help me design a machine I cant find it anywhere.
Anyone know what Im talking about?
Jim

PS Kip, do you live on a boat? That photo looks like it was taken looking to the side of a narrow boat or a broads cruiser.