Using Linear motion assemblies

[redbaron]

Has anyone built a CNC router using CNC motion assemblies? - The kind using an extruded aluminum structure with internal ballscrew and rails?

I just picked up 3 1500mm Techno-Isel Narrow slide assemblies off of ebay.

http://www.techno-isel.com/Search5/BallScrew_Slides.htm

I am wanting to us them in a dual XXYZ 4'x4' gantry type machine like the ShopBot.

Anyone know if they are rigid on their own or should I reinforce them with other rails. The photos on the site show them mounted to each other, but I wonder if they can withstand the force of cutting.

Thanks

[redbaron]

BUMP

Anyone???

[CNCadmin]

That's nice stuff, I sure many people have never seen that before.

[Hobbiest]

Are they telescopic? If not, I think they'd be plenty rigid, if so, may still be good enough. If they are telescopic, do a deflection test by rigid mounting the fixed end, and placing weight on the free end. Check with a dial gauge to see if there is any deflection. If you don't have a dial gauge, rig up a bracket that extends a bolt to the flat surface to be tested against. Extend the bolt so that a .004 or so feeler gauge just slips underneath. Once extended, it should still just slip underneath if there is no deflection. Start off with the .004 so that you can go down in size to find out the true deflection if any.