Re: [CAD_CAM_EDM_DRO] CNC router/mill controls

I'm new here. I have recently started researching building a CNC router
and converting mills to CNC. If any of the questions can be readily
answered with a link please direct me.

I'm going to assemble a router to learn how the things work and to gain
experience with the required equipment and software. I've been looking
around and have seen some products which are commonly used by CNC at
home people. I have a few questions.

I'm considering the Stepperworld FET-3 controller. To use with 3
PK266-03 steppers. This unit is affordable and seems to be good enough
for routing. It does halfstepping and I'm wondering if there is much to
be gained with 10x microstepping of the Gecko drives. Stepperworld does
not list all the specs like max stepping frequency and a few others
listed by Gecko etc.

How is the accuracy and size of the machine defined by the controller
board and lead screws? It seems that the machine has certain size and
speed limits based on the controller's limitations. Stepping frequency
and screw pitch define speed to some extent. How many steps per inch
before you're just reducing speed and not gaining accuracy? I've read
that if you want to do circular interpolation you need to use the same
screw pitch on X and Y axis. Is this a software or hardware(controller)
limitation? Is this also true for the Z if you intend to do 3D contouring.

Software seems to vary from freeware to industrial standard at 1000's of
dollars per license. Is there a site that weighs the pros and cons of
several types of software? Are there compatibility issues with
controllers and software? I guess that the software to operate the
machine can be run from DOS, Linux, or Windows. Most of the Gcode
generators would be Windows based? I'll be designing parts in SolidWorks.

My plan is to make a relatively accurate router, then find a larger
tabletop mill to convert for cutting aluminum. I'd go ahead and buy a
Sherline or similar to start with but the Y travel is not enough for
what I want to do.

Thanks for the help. Some of you may recognize me from RCGroups.

Gregory Kamysz
Crystal Lake, IL
USA