I get it now. Then maybe you could look at my last post in my next build and consider how I am making my gantry http://www.mycncuk.com/threads/6619-...0346#post60346
May be you would like some of mine ideas which i belive will lead to very strong gantry with no overhang and exclusively made from profiles, like the ones you have. That's the best I have come till now.