I am now committed

[breathe]

Well I am committed unless I sell everything that i have bought so far. Here is what I have already.

1x Gecko g540 3x Keling 381oz steppers some resistors. PSU from keling reccomended by crevicereamer.

47 inch star linear rails with carriages for both x and y axis.

I have a source for cheep 8020. have a router to use,

Need mach 3, some lead screws. Thinking acme rod and backlash nuts etc.

Any suggestions on the lead screw? Based on this setup how many tpi how many start etc. I like the idea of fast, but I would also like to be pretty accurate. maybe +/-.001 would be awesome. A little less is ok.


So in addition to the question about which lead screw for this setup I another question. I want to build a gantry style router. Why do people mount the linear ways on the sided of the extrusion vs the top?

I want a fully supported bottom, but most of the ones that I like have a beam runing underneath the table from one side of the gantry uprights to the other. Is this just for the lead screw?

If I use just one lead screw along one side of the x axis am I going to have problems with the machine twisting, or are the linear ways going to take care of that?

How high should I make my gantry if I am going to be using 15 inch linear way on the Z axis. How much movement will I be getting out of the Z axis with that setup?

Time to get this going. Trying to get some cad stuff going. Man am I slow. 20 minutes and I don't even have four square pieces for the base setup right. working progress.

[breathe]

QUICK QUESTION,

I am going to be using all 8020, or similar type extrusion, I am debating between two machine types. What are your opinions on these two types?

First one would be like this pic. http://crevicereamer.com/Page__57.html
Instead of steel I would use all aluminum. I don't care for the added complexity and margin for error on the gantry uprights and I don't care for the cross member under the table that allows the lead screw to be centered. I do like that the lead screw would not be torquing the gantry though.

Second design, very similiar to a solsylva. Gantry would be mounted directly to the frame with no uprights. Cutting area would be down below the main frame. What I don't like about this one is that I only want to use one lead screw on the x Axis. If I do that I may have trouble torquing my gantry. I plan to use 3/4'' linear rails with two 4'' long cars on each rail.

What say you my fellow hobbyist? I want a very rigid very accurate machine. Size is limited by linear rails which will be 47in long on each axis except for Z. Thanks all.