Hi Noplace, your frame needs a lot of bracing and strengthening as does your gantry. Have a look through some of the build logs and you'll see what I mean....these are two sililar to what I think you're aiming for?

http://www.mycncuk.com/threads/6988-routercnc_MK3

http://www.mycncuk.com/threads/8206-...Axis-CNC-Build