Re: [CAD_CAM_EDM_DRO] I need some help with a shopping list. . .

allenstepper wrote:

> I am a new member here and I am wanting to convert my Cinncinatti 1-D
> toolmaster (1967) mill into a CNC machine. I want to be able to
> control x,y, and z axis from my PC. Is there any easy way to do
> this? Is it possible to just take off the handwheels of the three
> axis and bolt on some drive motors hooked into the PC? Am I being to
> simplistic in my thinking? What kind of motors will I need to move
> the table? Right now it has a 1HP three phase. There is a fair
> ammount of backlash in the table as well ( about 25thous), will this
> mess everything up or does the backlash compensation from the
> software compensate that much?

Well, the original Acme screws can be made to work, but the results will
not be very good. .025" backlash cannot be compensated by software,
as the time it takes the motors to go from one side of the backlash to the
other is considerable. During that time, the table is not constrained by
the computer, it is free-floating. Also, the risk of an accident caused by
the table (and workpiece) being pulled into the cutting tool is a major
problem in certain operations. Climb milling would be out of the question
except for the lightest finish passes. Any attempt to make large circular
holes or pockets would come out with bumps at the points where each
axis reverses. I have .0015" backlash (some in the ballscrews, some in
flex in the machine, rocking of the table, etc.) and it causes my circles
to be out of round. With 20 x the backlash, ouch! Also, with this much
wear, the screws are also worn, and so there will be varying backlash
at different positions.

You really need to tell us what you intend to do with this machine. Some
people want a fancy machine to drill holes, and +/- .010" accuracy and
.005" repeatability is fine for them. others want to make miniature Merlin
engines or jet engines, and they really are serious about holding tolerances

to .002" or so on the finished part. So, without further detail, it is hard

to advise.

I don't know the Cinci 1D, is it about the size of the standard Bridgeport,
and a knee mill?

Jon