Dave's Router

[daveshorts]

After a long interval - due to having many other things to build (most of which could have done with a CNC router - but the timings didn't work), I am starting to think about getting back to it.

I was going to use 20mm unsupported round steel rails for the Z axis. I was going to attach the rails to a plank of 12mm aluminium at each end. But just having received the rod and looked at it, it seems pretty rigid, the aluminium is going to involve more machining and use up space (I can probably get the router 20mm closer to the Y axis without it.

So I was wondering if I could get away with just clamping the router support at one end of the rails, and a stepper motor support at the other end, and just use the rails and a ballscrew for the axis, with no scaffolding. It is going to be a bit less stiff but not hideously so as the rails were unsupported anyway, possibly a bit more prone to twisting, but this isn't going to move the router very much, and the rails have got 4 well spread out bearings.

I haven't seen a design like this so was wondering if anyone else has done this and have I failed to think of a critical bending mode?