Background:

A friend who saw the 3-1/2 axis CNC joinery machine I'm building
suggested that it might be a good idea to offer a 3-axis version of
the machine in kit form. It would be identical to the joinery machine
except that the z-axis could not be tilted.

The machine would use four 200 inch*ounce stepper motors producing 400
half-steps per revolution to drive 3/8"-12 TPI Acme lead screws - two
motors on the x-axis and one on each of the y- and z-axis. This
results in a linear step size of 1/4800" and (ignoring frictional
losses) increases the "oomph" of the 200 oz*in steppers by a factor of
12. Speed of movement will be limited by the speed of the controlling
PC; but 5"/sec is probably not an unreasonable expectation for
moderately slow machines.

The nominal work space (the actual range of movement will be larger)
is 12" x 12" x 4" (x, y, z).

There are four main groups of parts involved: (1) The wooden
structure, (2) The electricals (a controller box that plugs into a PC
printer port and provides power to the steppers - and the four stepper
motors), (3) the collection of hardware (bolts, washers, nuts, rails,
bearings, etc.), and (4) software to convert drawing (DXF) files to
CNC command files, and software that reads the command files and
communicates with the controller box to produce stepper activity.

Installing the software is a matter of downloading and un-zipping the
two packages. One of the packages requires registration and a $60
registration fee - and doing a fill-in-the-blanks configuration. I
don't provide either package; but feel that the package which requires
registration is a bargain.

Assembling the structure is quick and easy (15-30 minutes with an
allen wrench).

Assembling the controller box is probably an all-day job for most
people. It involves drilling, soldering, tapping holes, and a bit of
screwdriver work.

Some of the hardware requires cutting, drilling, and tapping metal and
plastic blanks. Most of these operations don't require what I think of
as advanced skills; but I'm aware that there may be woodworkers with
no metalworking experience at all. There is perhaps a day's work
involved.

My questions:

* Would anyone be interested in such a small machine?

* Should I expect kit builders to assemble the controller or should I
pre-assemble it and increase the price to include that labor - or
should I offer this as an option?

* Should I expect kit builders to do the preparatory operations on the
hardware, should I do that myself and build it into the kit price, or
should I offer this as an option?

* Should I discard the kit idea altogether and just offer finished
packages?

* Any other thoughts / suggestions?

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto