Right!  I forgot to mention that part:).  The cross slide screw would need to be removed.  Take out the two screws and thread out of the nut.  Reverse the operation to put it back in.  The apron should already be free to move on the rack as long as the power feed is not engaged.  Great question!

Thanks for the feedback evenstevens.  I hear you on the mistakes that could happen on the Z axis and the importance of protecting the screws.  Any other major flaws that you can see with this concept?  Is this worth pursuing or is this just another flavor on what's already been done or even been done better?

I think the most important aspect of any CNC machine has got to be the "trapping" which is to say the designs ability to restrict movement in the directions undesired while allowing movement in the directions desired. This does not clearly show that aspect. any chance you could show the device as a semi transparent design? I am working on a design that initially will be a cheap $300 kit that will allow a person to use off the shelf parts to complete and if they want to build a bigger machine they can either order more parts that go to the kit and expand the size of the rails, or they can use the kit and a simple vector line art program to design a similar machine kit and cut their own design that is similar to my design. the material is like a super hard sponge so it will hold tolerances under moderate vibrational levels such as a router or dremel cutting a part, while resisting deformation unlike metals and other solid materials that suffer from both deformation a little at a time (imagine tapping on a piece of metal with a hammer over a long time then increase the speed of the tap to 10's of 1000's of times a minute. this is what happens in a CNC machine made of steel or aluminum, where these are used to make the frame.) I am calling this vibrational creep since it is a form of creep caused by vibrations, and only during vibrational impacts.)

once I have reached my goal financially to allow for further design and development of other technologies, it will (along with G-code) be released as an open source file package. Hopefully then CNC machines will become truly available to everyone.


also to note I am including a packet of info that will grow hopefully with user input, on where to obtain supplies from salvage and reclaim them. I am using roller bearings in my design and have found that going to say thriftstores and buying up inline skates provides these are a lot less expense, and that most of the bearings are only dirty and not damaged, so flushing them with a simple tool I make with a piece of vinyl hose, a funnel, piece of threaded rod and two nuts, and a hand drill, brings them back to life. and any oil will work as long as it retards rust. I start with used motor oil to flush out the big debris, and then switch to new motor oil, to flush out the micro debris from the used oil. also I found that adding prolong to the oil or using used motor oil that had prolong added to it, leaves the bearings about as speedy as you can get, other than prolong treatment of brand new bearings heh heh,

another trick I have is tearing apart new dead LCD and older plasma TVs as around the screen there is usually a decent thickness aluminum angle that can be salvaged and used for brackets and reinforcement.

just as an example of what will be coming along with this kit that in a while will be opensource.

I have not used counterbalancing for backlash but I do use a pulley and weight system to allow a smaller motor to move a fairly large head up and down to cut parts. works like a charm. speed is what it should be, and the wear on the lead nut and lead screw is diminished dramatically.