Hey peeps why all the negative vibes???
I'm just playing at this anyway... We all can't afford the expensive linear rails
plus this isn't something I'm building to last I just wanna cut a bit of ply

I've seen plenty in mdf that work perfectly well. If I wanted to spend 3k plus I'd be building from steel but I don't. I have a wood work shop and all of this was stuff I had kicking about damaged boards etc so it's free so far. If it doesn't work I won't loose much sleep about it. If at the end I fancy a posher job I'll design something I bit better. So please don't shoot me down this is supposed to be a friendly forum not cocks are us!
Hi boyan I'm going to use 25mm ball screws for the main gantry 30mm would of been a bit better speed wise but as its a mdf build I won't be running a very high speeds I've yet to spec the steppers which I'll do when I've done the calcs. I agree I may need to stiffen things up a tad and Vee bearings were my second choice but cost wise I couldn't knock them as I found a job lot for £45 quid
Ive got a job I thought it would be handy for so as long as it does a decent enough job cutting some shapes from 18mm ply it's saved me having to sub the job out. If it doesn't it'll keep the boiler burning for a month or so!